Catalysts

18 pages, 3150 KB

Open AccessEditor’s ChoiceArticle

Engineering Hierarchical NiMo/USY Catalysts for Selective Hydrocracking of Naphthalene to BTX

by Haidong Li, Mingjia Liu, Yifang Zhang, Xiu Chen, Kunyi Zheng, Xilong Wang, Penglei Ni and Jun Ma

Catalysts 2026, 16(1), 31; https://doi.org/10.3390/catal16010031 - 31 Dec 2025

Viewed by 365

Abstract

The selective hydrocracking of polycyclic aromatic hydrocarbons to BTX requires precise control over catalyst porosity and metal–acid balance. Hierarchical porosity, integrating microporous and mesoporous networks, is pivotal for enhancing mass transport and regulating reaction pathways. USY zeolites were engineered to create distinct hierarchical [...] Read more.

The selective hydrocracking of polycyclic aromatic hydrocarbons to BTX requires precise control over catalyst porosity and metal–acid balance. Hierarchical porosity, integrating microporous and mesoporous networks, is pivotal for enhancing mass transport and regulating reaction pathways. USY zeolites were engineered to create distinct hierarchical architectures via HCl, urea, and NaOH–surfactant treatments. HCl treatment constructed a gradient pore acidity system, urea treatment enhanced acidity while preserving microporosity, and NaOH–surfactant fabricated ordered mesopores with reduced acidity. The catalyst with the HCl-engineered gradient pore (NiMo/YH-1) achieved a 91% BTX yield at 425 °C in naphthalene hydrocracking, outperforming others. This performance is attributed to its gradient structure that enforces an optimal “hydrogenation-then-cracking” pathway, highlighting the critical role of tailored hierarchical porosity. Full article

(This article belongs to the Section Catalytic Reaction Engineering)

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16 pages, 2470 KB

Open AccessEditor’s ChoiceArticle

Amorphous Nano Zero-Valent Iron (A-nZVI) Modified by Ethylenediamine for Efficient Dechlorination of Trichloroethylene: Structure, Kinetics, and Mechanism

by Zhidong Zhao, Yuqi Qiu, Baoliang Lei, Chenyang Zhang, Zhanhe Liu, Wei Wang, Haitao Wang and Tielong Li

Catalysts 2025, 15(12), 1173; https://doi.org/10.3390/catal15121173 - 18 Dec 2025

Viewed by 582

Abstract

Amorphous nano zero-valent iron (A-nZVI) was synthesized via liquid-phase reduction and ethylenediamine (EDA) modification to enhance trichloroethylene (TCE) dechlorination. A-nZVI showed a cauliflower-like morphology, where 20–50 nm primary particles formed 500–1000 nm secondary agglomerates with a high surface area. Compared with crystalline nZVI [...] Read more.

Amorphous nano zero-valent iron (A-nZVI) was synthesized via liquid-phase reduction and ethylenediamine (EDA) modification to enhance trichloroethylene (TCE) dechlorination. A-nZVI showed a cauliflower-like morphology, where 20–50 nm primary particles formed 500–1000 nm secondary agglomerates with a high surface area. Compared with crystalline nZVI (C-nZVI), A-nZVI exhibited higher electron transfer efficiency and stronger reducing capability (potentiodynamic polarization analysis). TCE removal followed a two-stage model: a rapid adsorption–reduction phase (pseudo-second-order; q_e = 9.48 mg/g, R² = 0.998) and a slower degradation phase (pseudo-first-order; k = 0.0125 h⁻¹, R² = 0.994). No toxic intermediates (e.g., dichloroethylene or vinyl chloride) were detected; products were mainly acetylene, ethylene, and ethane. The electron utilization efficiency increased from 8.47% (C-nZVI) to 15.32% (A-nZVI), while hydrogen evolution decreased by 32%. EDA formed Fe–N coordination bonds that facilitated electron transfer and stabilized the amorphous structure. A-nZVI retained 40% of its activity after four cycles under neutral to alkaline conditions. Full article

(This article belongs to the Section Environmental Catalysis)

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18 pages, 1129 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Controlled Sequential Oxygenation of Polyunsaturated Fatty Acids with a Recombinant Unspecific Peroxygenase from Aspergillus niger

by Carlos Renato Carrillo Avilés, Marina Schramm, Sebastian Petzold, Miguel Alcalde, Martin Hofrichter and Katrin Scheibner

Catalysts 2025, 15(12), 1162; https://doi.org/10.3390/catal15121162 - 11 Dec 2025

Viewed by 638

Abstract

The metabolism of polyunsaturated fatty acids (PUFAs) is a broad research field, and the products identified so far offer potential medical and industrial applications. Epoxy fatty acids (EpFAs) act as lipid mediators that modulate renal function, angiogenesis, vascular dilatation and inflammation; moreover, they [...] Read more.

The metabolism of polyunsaturated fatty acids (PUFAs) is a broad research field, and the products identified so far offer potential medical and industrial applications. Epoxy fatty acids (EpFAs) act as lipid mediators that modulate renal function, angiogenesis, vascular dilatation and inflammation; moreover, they regulate monocyte aggregation and are involved in cardiovascular and metabolic diseases. On the other hand, EpFAs are precursors of environmentally friendly products for the plastics industry, in which the grade of epoxidation of the compounds gives the polymeric material different advantageous characteristics. The controlled chemical synthesis of poly epoxidized PUFAs is challenging as the reactions are non-selective. In contrast, the biosynthetic route based on cytochrome P450 monooxygenases and lipoxygenases is highly selective but ineffective due to the instability of the enzymes in cell-free systems. Fungal unspecific peroxygenases (UPOs, EC 1.11.2.1) with P450-like activity offer a suitable alternative for the selective synthesis of EpFAs from PUFAs. Here we demonstrate that a recombinant unspecific peroxygenase from Aspergillus niger (rAniUPO) is able to sequentially epoxidize eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) to 14,15-17,18 diepoxyeicosatrienoic acid (14,15-17,18 diEpETrE) and 16,17-19,20-diepoxydocosatetraenoic acid (16,17-19,20 diEpDTE), respectively, while arachidonic acid is transformed into 13-hydroxy-14,15-epoxyeicosatrienoic acid (14,15-hepoxilin B₃). Optimal production for these oxygenated derivatives (up to 15 mg) was achieved using 2 mM hydrogen peroxide as the co-substrate. The obtained molecules were identified using high-resolution mass spectrometry and their structure was verified by NMR. Our results demonstrate the suitability of UPOs for the synthesis of EpFAs that can be used in medical research and industrial applications. Full article

(This article belongs to the Special Issue 15th Anniversary of Catalysts: The Future of Enzyme Biocatalysis)

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30 pages, 2987 KB

Open AccessEditor’s ChoiceReview

High-Entropy Materials for Photocatalysis: A Mini Review

by Wenhao Bai, Fei Chang, Kaiwen Li, Yujjie Kou and Wei Tian

Catalysts 2025, 15(12), 1152; https://doi.org/10.3390/catal15121152 - 5 Dec 2025

Viewed by 1324

Abstract

In recent years, high-entropy materials (HEMs) have emerged as a promising multifunctional material system, garnering significant interest in the field of photocatalysis due to their tunable microstructures, diverse compositions, and unique electronic properties. Owing to their multi-element synergistic effects and abundant active sites, [...] Read more.

In recent years, high-entropy materials (HEMs) have emerged as a promising multifunctional material system, garnering significant interest in the field of photocatalysis due to their tunable microstructures, diverse compositions, and unique electronic properties. Owing to their multi-element synergistic effects and abundant active sites, high-entropy photocatalysts enable precise regulation over the separation efficiency of photo-generated charge carriers and surface reaction pathways, thereby significantly enhancing photocatalytic activity and selectivity. The high configurational entropy of these materials also imparts exceptional structural stability, allowing the catalysts to maintain long-term durability under harsh conditions, such as intense light irradiation, extreme pH levels, or redox environments. This provides a potential alternative to common issues faced by traditional photocatalysts, such as rapid deactivation and short lifespans. This review highlights recent advancements in the preparations and applications of HEMs in various photocatalytic processes, including the degradation of organic pollutants, hydrogen production, CO₂ reduction and methanation, H₂O₂ production, and N₂ fixation. The emergence of high-entropy photocatalysts has paved the way for new opportunities in environmental remediation and energy conversion. Full article

(This article belongs to the Collection Catalysis in Advanced Oxidation Processes for Pollution Control)

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21 pages, 2505 KB

Open AccessFeature PaperEditor’s ChoiceReview

Bridging Disciplines in Enzyme Kinetics: Understanding Steady-State, Transient-State and Performance Parameters

by Yu Ma and Bekir Engin Eser

Catalysts 2025, 15(12), 1139; https://doi.org/10.3390/catal15121139 - 4 Dec 2025

Cited by 1 | Viewed by 2694

Abstract

Enzyme kinetics is fundamental across diverse fields—from enzymology and medicine to biocatalysis and metabolic engineering. Analyses of enzyme kinetics provide insights into catalytic rates, substrate affinities, inhibition patterns, productivities and mechanistic pathways, which are critical for areas such as drug development, industrial biocatalysis [...] Read more.

Enzyme kinetics is fundamental across diverse fields—from enzymology and medicine to biocatalysis and metabolic engineering. Analyses of enzyme kinetics provide insights into catalytic rates, substrate affinities, inhibition patterns, productivities and mechanistic pathways, which are critical for areas such as drug development, industrial biocatalysis and mechanistic enzymology. However, each research field emphasizes different types of kinetic parameters, leading to challenges in establishing a common ground for understanding and interpreting enzyme properties. This review covers interpretation of enzyme kinetic parameters under three main categories—steady-state, transient-state and performance metrics—in a descriptive way and discusses their relevance with respect to different scientific and applied fields that investigate and utilize enzymes. By comparatively defining key kinetic and thermodynamic parameters, the review aims to help researchers interpret and report enzyme behavior more effectively, bridging gaps across interdisciplinary fields. Full article

(This article belongs to the Special Issue State-of-the-Art Enzyme Engineering and Biocatalysis in Europe)

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15 pages, 1420 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Pyrolysis of Corn Straw for In Situ Dechlorination of Bio-Oil Under the Catalysis of Acidified-γ-Al₂O₃ Modified with Alkaline and Alkaline Earth Metal Compounds

by Wenkai Zhang, Ze Wang and Songgeng Li

Catalysts 2025, 15(12), 1142; https://doi.org/10.3390/catal15121142 - 4 Dec 2025

Viewed by 501

Abstract

Bio-oil’s high chlorine content severely hinders its application, because of its high corrosivity. Catalytic pyrolysis is an effective method for the dechlorination of bio-oil. Herein, the performances of the acidified-γ-Al₂O₃ modified with alkaline and alkaline earth metal compounds were investigated. [...] Read more.

Bio-oil’s high chlorine content severely hinders its application, because of its high corrosivity. Catalytic pyrolysis is an effective method for the dechlorination of bio-oil. Herein, the performances of the acidified-γ-Al₂O₃ modified with alkaline and alkaline earth metal compounds were investigated. It was found that NaOH was a better loading material than Ca(NO₃)₂ or Mg(NO₃)₂ in the support of acidified-γ-Al₂O₃. The optimal loading amount of NaOH was 5 wt% in the range of 1 wt%–15 wt%, and the better calcination temperature was 600 °C, compared with 800 °C. When catalyzed with Na/Al₂O₃ (5%, 600 °C), the organic chlorides content in bio-oil from the pyrolysis of corn straw at 500 °C was significantly reduced from 150 ppm to 29 ppm, while the inorganic chlorides content barely changed. NaAlO₂ was generated in Na/Al₂O₃ from the solid-phase reaction between NaOH and Al₂O₃ by calcination. When Na/Al₂O₃ (5%,600 °C) and Na₂CO₃ were both used in two layers in a fixed-bed reactor, the organic and inorganic chlorides in bio-oil simultaneously significantly decreased, respectively, to 57 ppm and 23 ppm. The decrease in chlorides benefits the deep dechlorination of bio-oil by absorption or catalytic hydrodechlorination in a post-treatment process, which reduces the consumption of absorbent or hydrogen. Full article

(This article belongs to the Special Issue Integrating Pyrolysis with Catalysis: A Pathway to Sustainable Chemicals)

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26 pages, 2563 KB

Open AccessFeature PaperEditor’s ChoiceReview

Advances in Strategies for In Vivo Directed Evolution of Targeted Functional Genes

by Hantong Wu, Lang Yin, Jingwen Chen, Xin Wang and Kequan Chen

Catalysts 2025, 15(12), 1127; https://doi.org/10.3390/catal15121127 - 2 Dec 2025

Viewed by 1789

Abstract

Enzymes are indispensable in fields such as biotechnology, medicine, and industrial manufacturing due to their high catalytic specificity and efficiency under mild conditions. However, their natural versions often suffer from limitations, including low activity toward non-natural substrates, poor stability under extreme conditions, and [...] Read more.

Enzymes are indispensable in fields such as biotechnology, medicine, and industrial manufacturing due to their high catalytic specificity and efficiency under mild conditions. However, their natural versions often suffer from limitations, including low activity toward non-natural substrates, poor stability under extreme conditions, and narrow substrate spectra. Directed evolution, a key protein engineering strategy that optimizes protein function via genetic diversity introduction and directed selection, has become the primary solution to these limitations. Among its mature methodological systems, in vivo evolution platforms (advanced by synthetic biology) are particularly efficient, as they integrate in-cell mutation, translation, selection, and replication into an automated process, significantly improving experimental efficiency. This review will focus on two core strategies that enhance these platforms: in vivo targeted gene hypermutation and heterologous polymerase-mediated targeted hypermutation. These techniques enable the rapid optimization of enzymes to acquire novel functions, as well as the comprehensive engineering of microbial strains to enhance their performance and stress tolerance. Analyzing these strategies provides a robust technical framework for enzyme engineering and promises to drive future innovations across multiple fields. Full article

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15 pages, 1996 KB

Open AccessEditor’s ChoiceArticle

Interplay Between Ionic Liquids, Kolbe Chemistry, and 2D Photocatalyst Supports in Aqueous CO₂ Photoreduction over Pd/TiO₂ and Pd/g-C₃N₄

by Yulan Peng, Pierre-Yves Dugas, Kai-Chung Szeto, Catherine C. Santini and Stéphane Daniele

Catalysts 2025, 15(12), 1128; https://doi.org/10.3390/catal15121128 - 2 Dec 2025

Viewed by 493

Abstract

The photocatalytic reduction of CO₂ in aqueous media offers a sustainable route for solar-to-fuel conversion, yet remains challenged by CO₂’s thermodynamic stability and kinetic inertness, low solubility, and competitive hydrogen evolution. Here, we investigate the interplay between ionic liquids (ILs), [...] Read more.

The photocatalytic reduction of CO₂ in aqueous media offers a sustainable route for solar-to-fuel conversion, yet remains challenged by CO₂’s thermodynamic stability and kinetic inertness, low solubility, and competitive hydrogen evolution. Here, we investigate the interplay between ionic liquids (ILs), photocatalyst supports, and additive composition in directing product selectivity among CO, CH₄, and H₂. Using imidazolium acetate as a benchmark, we demonstrate that ILs not only pre-activate CO₂ but can also undergo decomposition pathways under illumination, notably Kolbe-type reactions leading to methane formation from acetate rather than from CO₂. Comparative studies of Pd-decorated TiO₂ and g-C₃N₄ nanosheets reveal distinct behaviors driven by their interfacial interactions with the imidazolim-based ionic liquid: weak interaction with TiO₂ strongly promotes hydrogen evolution, whereas strong coupling with g-C₃N₄ synergizes with C₁C₄ImOAc to trigger acetate-derived Kolbe reactivity. The systematic evaluation of alternative salts confirms the determinant role of anion basicity and medium-pH-basic anions facilitate CO₂ activation, whereas weakly basic or non-coordinating anions favor water splitting. Overall, these results clarify the dual role of ionic liquids as both CO₂ activators and sacrificial agents, and highlight design principles for improving product selectivity and efficiency in aqueous CO₂ photoreduction systems. Full article

(This article belongs to the Special Issue Ionic Liquids and Deep Eutectic Solvents in Catalysis)

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30 pages, 3460 KB

Open AccessEditor’s ChoiceArticle

Steam-Induced Aluminum Speciation and Catalytic Enhancement in ZSM-5 Zeolites

by Luigi Madeo, Niels Blom, Finn Joensen, Janos B. Nagy and Pierantonio De Luca

Catalysts 2025, 15(12), 1130; https://doi.org/10.3390/catal15121130 - 2 Dec 2025

Viewed by 654

Abstract

ZSM-5 zeolites with varying aluminum content were subjected to steam treatments of different severities by adjusting the temperature, duration, and water vapor pressure. The steamed samples were characterized using a range of analytical techniques. A quantitative assessment of the aluminum species—namely, tetrahedrally coordinated [...] Read more.

ZSM-5 zeolites with varying aluminum content were subjected to steam treatments of different severities by adjusting the temperature, duration, and water vapor pressure. The steamed samples were characterized using a range of analytical techniques. A quantitative assessment of the aluminum species—namely, tetrahedrally coordinated framework Al, dislodged framework Al, non-framework pentacoordinated Al, and non-framework hexacoordinated Al—was achieved through a combination of EDX analysis on Cs-exchanged materials and quantitative ²⁷Al MAS NMR spectroscopy, including spectral simulation. Contrary to previous reports, the catalytic activity per framework Al site in unsteamed ZSM-5 increases with aluminum content at low Si/Al ratios, aligning with recently proposed medium effects. Notably, at the point of maximum activity enhancement due to steaming, equivalent amounts (1:1) of framework and dislodged framework Al—both in tetrahedral coordination—are observed. The maximum enhancement factor per framework Al site, for a given material and reaction, remains independent of the specific steaming conditions (temperature, time, and pressure). However, the degree of activity enhancement varies with the type of reaction: it is more pronounced for n-hexane cracking (α-test) than for m-xylene isomerization. This suggests that both catalyst modification and reaction characteristics contribute to the observed steam-induced activity enhancement. A synergistic interaction between Brønsted and Lewis acid sites appears to underpin these effects. One plausible mechanism involves the strengthening of Brønsted acidity in the presence of adjacent Lewis acid sites. This enhancement is expected to be more significant for n-hexane cracking, which demands higher acid strength compared to m-xylene isomerization. In cases of n-hexane cracking, the increased acid strength and the formation of olefins via reactions on Lewis acid sites may act cooperatively. Importantly, the dislodged framework Al species—tetrahedrally coordinated in the hydrated catalyst at ambient temperature and functioning as Lewis acid sites in the dehydrated zeolite under reaction conditions—are directly responsible for the observed enhancement in acid activity. The transformation of framework Al into dislodged framework Al species is reversible, as demonstrated by hydrothermal treatment of the steamed samples at 150–200 °C. Nonetheless, reinsertion of Al into the framework is not fully quantitative: a portion of the dislodged framework Al is irreversibly converted into non-framework penta- and hexacoordinated species during the hydrothermal process. Among these, non-framework pentacoordinate Al species may serve as counterions to balance the lattice charges associated with framework Al. Full article

(This article belongs to the Special Issue Zeolites and Zeolite-Based Catalysis: Development, Application and Challenges)

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15 pages, 3864 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Investigation of the Synergistic Aromatization Effect During the Co-Pyrolysis of Wheat Straw and Polystyrene Modulated by an HZSM-5 Catalyst

by Zhenhong Cai, Yongkang Ye, Akash Kumar, Hongwei Rong, Baihui Cui, Fang Zhang and Dabin Guo

Catalysts 2025, 15(12), 1121; https://doi.org/10.3390/catal15121121 - 1 Dec 2025

Viewed by 636

Abstract

To achieve the high-value utilization of agricultural and plastic wastes, the catalytic co-pyrolysis behavior of wheat straw (WS) and polystyrene (PS) was systematically investigated using HZSM-5 zeolite as a catalyst. The results revealed that oxygenates and aliphatic hydrocarbons derived from WS pyrolysis were [...] Read more.

To achieve the high-value utilization of agricultural and plastic wastes, the catalytic co-pyrolysis behavior of wheat straw (WS) and polystyrene (PS) was systematically investigated using HZSM-5 zeolite as a catalyst. The results revealed that oxygenates and aliphatic hydrocarbons derived from WS pyrolysis were efficiently converted into aromatics over the HZSM-5 catalyst, increasing the yield of monocyclic aromatic hydrocarbons (MAHs) from 7.8% to 30.3%. A significant synergistic effect was observed at a WS:PS ratio of 60:40, where the yield of BTX (benzene, toluene, and xylene) reached 41.1%, exceeding the levels achieved from the catalytic pyrolysis of either WS or PS alone. This synergy originates from the reconstruction of reaction pathways: the hydrogen-rich environment generated by PS promoted hydrodeoxygenation of biomass, which suppressed CO₂ formation (−16%) and enhanced carbon atom utilization; meanwhile, HZSM-5 facilitated dealkylation and alkyl transfer reactions, leading to an increase in benzene production (+12%). Moreover, elevating the catalytic temperature helped to inhibit the formation of polycyclic aromatic hydrocarbons (PAHs) and further increased the MAH yield. These findings provide a valuable reference and experimental basis for the synergistic conversion of waste materials into high-value-added aromatics. Full article

(This article belongs to the Special Issue Catalytic Valorization and Utilization of Biomass and Biomass Derivatives)

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14 pages, 7287 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Conversion of Syngas to Long-Chain α-Olefins over Rh-Promoted CoMnO_x Catalyst

by Yuting Dai, Xuemin Cao, Fei Qian, Xia Li, Li Zhang, Peng He, Zhi Cao and Chang Song

Catalysts 2025, 15(12), 1122; https://doi.org/10.3390/catal15121122 - 1 Dec 2025

Viewed by 635

Abstract

The direct synthesis of long-chain α-olefins from syngas offers a strategically vital pathway for producing high-value chemicals from alternative carbon resources. However, achieving high selectivity toward C₅₊ olefins remains challenging due to competing paraffin formation and difficulties in precisely regulating chain growth [...] Read more.

The direct synthesis of long-chain α-olefins from syngas offers a strategically vital pathway for producing high-value chemicals from alternative carbon resources. However, achieving high selectivity toward C₅₊ olefins remains challenging due to competing paraffin formation and difficulties in precisely regulating chain growth kinetics. To mitigate these critical challenges, a series of Rh-promoted Co-Mn catalysts supported on SiO₂ were synthesized using a carbon-mediated impregnation strategy for the direct conversion of syngas to long-chain α-olefins (C₅₊). The introduction of Rh significantly enhanced both catalytic activity and C₅₊ olefin selectivity. The optimal 1.1 wt% Rh-loaded catalyst achieved 24.6% CO conversion and 46.0% total olefin selectivity, with 34.2% of the selectivity toward C₅₊ olefins, while maintaining low CH₄ (6.2%) and CO₂ (<1%) selectivity. Comprehensive characterization techniques, including XRD, H₂-TPR, XPS, and TEM/HAADF-STEM, revealed that the carbon-mediated method facilitated the formation of highly dispersed Co₃O₄ nanoparticles with abundant oxygen vacancies and strengthened the Co-MnO_x interface. Rh promotion modulated the cobalt speciation (Co⁰/Co²⁺), improved reducibility, and enhanced the metal-support interaction. This promoted chain growth and olefin desorption while suppressing over-hydrogenation. This study demonstrates the efficacy of Rh promotion and carbon mediation in designing high-performance Fischer-Tropsch catalysts for selective α-olefin synthesis, offering new insights into the design of efficient metal-oxide interfacial catalysts. Full article

(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section, 2nd Edition)

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16 pages, 6647 KB

Open AccessEditor’s ChoiceArticle

The Effect of Nickel Content on a NiMoS Catalyst for Deep Hydrodearomatisation of Polycyclic Aromatic Hydrocarbons

by Qianmin Jiang, Da Wu, Shuandi Hou, Zixian Jia and Zhentao Chen

Catalysts 2025, 15(12), 1111; https://doi.org/10.3390/catal15121111 - 29 Nov 2025

Viewed by 455

Abstract

A series of NiMo catalysts with a low MoO₃/NiO mass ratio were prepared by introducing SiO₂ and Ni during the formation of the support. The supports were improved by adding SiO₂ to optimise the surface acidity properties, regulate the [...] Read more.

A series of NiMo catalysts with a low MoO₃/NiO mass ratio were prepared by introducing SiO₂ and Ni during the formation of the support. The supports were improved by adding SiO₂ to optimise the surface acidity properties, regulate the main structure of the NiMoS active phase, reduce the formation proportion of NiAl₂O₄, and improve the utilisation rate of Ni. The catalysts were improved by increasing the Ni content to adjust the Ni/Mo atomic ratio at the edge and corner positions of the NiMoS active phase to promote the generation and transfer of activated hydrogen. The NiMoS phase with high Ni content achieved good dispersion on the catalyst surface, reaching the highest hydrogenation saturation depth of aromatic hydrocarbon when the MoO₃/NiO mass ratio is 3 and the SiO₂ content is 5 wt.%. The catalysts with high Ni content also exhibit high activity and stability in removing Conradson Carbon Residue (CCR) during hydrotreating. Increasing the Ni content of the catalyst helps to remove impurities such as S and N from the residual oil. Full article

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18 pages, 2712 KB

Open AccessEditor’s ChoiceArticle

Niobium-Enhanced Kinetics of Tantalum Phosphate in Catalytic Glucose Dehydration to 5-Hydroxymethylfurfural

by Da-Ming Gao, Kai Huang, Jianxing Zheng, Lei Gong, Junli Ren, Hidemi Fujino and Haichao Liu

Catalysts 2025, 15(12), 1095; https://doi.org/10.3390/catal15121095 - 21 Nov 2025

Viewed by 855

Abstract

The application of water-tolerant bifunctional solid acids with high kinetic performance in converting glucose to 5-hydroxymethylfurfural (HMF) presents a number of challenges. In this study, the effect of doping a hierarchically porous tantalum phosphate monolith with transition metal ions (Nb⁵⁺, V [...] Read more.

The application of water-tolerant bifunctional solid acids with high kinetic performance in converting glucose to 5-hydroxymethylfurfural (HMF) presents a number of challenges. In this study, the effect of doping a hierarchically porous tantalum phosphate monolith with transition metal ions (Nb⁵⁺, V⁵⁺, Zr⁴⁺, Ni²⁺, and Zn²⁺) was explored in delivering superior glucose dehydration kinetics and stability. Doping with Nb⁵⁺ (x%Nb-TaP) resulted in the best catalytic performance with enhanced tantalum phosphate stability. The incorporation of Nb⁵⁺ ions inhibited tantalum phosphate crystallization, increased the density of Lewis acid and Brønsted acid sites and average mesopore size, with consequently enhanced kinetics, enabling the reaction kinetics of fructose to approach a steady state. Application of a 25% mol/mol Nb (25%Nb-TaP) activated at 600 °C to convert 1.0 wt.% glucose in a water/methyl isobutyl ketone (MIBK) biphasic system delivered an HMF yield and selectivity of 72.6% and 95.6%, respectively. Moreover, an HMF productivity of 0.11 mol·h⁻¹·kg-solution⁻¹ was achieved by treating a 15.0 wt.% glucose feed at 170 °C in a water/MIBK biphasic system at a catalyst loading of 10.0 wt.%. The 25%Nb-TaP catalyst largely retained its initial activity after three recycles in the water/MIBK biphasic system, generating an HMF yield of 54.1% and selectivity of 87.0%. The results of this study demonstrate the significant potential of Nb-TaP for industrial-scale HMF production. Full article

(This article belongs to the Special Issue Catalytic Conversion of Carbohydrates into Platform Chemicals)

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24 pages, 5091 KB

Open AccessEditor’s ChoiceArticle

Simulation of CO₂ Catalytic Absorption Process Using Amine Solutions Based on the Lattice Boltzmann Method

by Binbin Zhang, Nuogeng Sun, Ming Luo, Jing Jin, Qiulin Wang and Huancong Shi

Catalysts 2025, 15(11), 1093; https://doi.org/10.3390/catal15111093 - 20 Nov 2025

Viewed by 861

Abstract

Carbon emission reduction strategies are crucial for addressing global climate change, with chemical absorption-based carbon capture technology being one of the core methods for achieving large-scale CO₂ mitigation. The current research focus in chemical absorption lies in selecting blended amine–catalyst systems and [...] Read more.

Carbon emission reduction strategies are crucial for addressing global climate change, with chemical absorption-based carbon capture technology being one of the core methods for achieving large-scale CO₂ mitigation. The current research focus in chemical absorption lies in selecting blended amine–catalyst systems and applying efficient absorption–desorption equipment. This study employs the Lattice Boltzmann Method (LBM) to simulate the catalytic CO₂ absorption process within an absorption column, obtaining data such as solution flow velocity, CO₂ absorption rate, and temperature distribution. The simulation results align well with experimental data from a continuous pilot-scale setup. Furthermore, the effects of different operating parameters and catalyst conditions on the absorption process were investigated. The findings indicate that higher catalyst volume fractions and smaller catalyst particle sizes enhance CO₂ absorption but may also lead to significant temperature rises across the column. Additionally, an optimized ternary amine–catalyst combination should be selected over a single amine to achieve superior CO₂ absorption capacity. Provided that the cyclic loading capacity is maintained, the absorbent solution flow rate should be minimized to ensure optimal absorption efficiency. Full article

(This article belongs to the Section Environmental Catalysis)

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18 pages, 2897 KB

Open AccessEditor’s ChoiceArticle

Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid over a Bi-Promoted Pt/Al₂O₃ Catalyst

by Juan Du, Wanting Qiu, Sunbal Ayaz, Jian Long, Wenze Guo, Ling Zhao and Zhenhao Xi

Catalysts 2025, 15(11), 1088; https://doi.org/10.3390/catal15111088 - 18 Nov 2025

Cited by 1 | Viewed by 1077

Abstract

2,5-furandicarboxylic acid (FDCA), a high-value biomass-derived monomer, serves as a crucial building block for sustainable polymers including polyesters, polyamides, and polyurethanes. This study systematically investigated the catalytic oxidation of 5-hydroxymethylfurfural (HMF) to FDCA over Pt/Al₂O₃ and Pt–Bi/Al₂O₃ [...] Read more.

2,5-furandicarboxylic acid (FDCA), a high-value biomass-derived monomer, serves as a crucial building block for sustainable polymers including polyesters, polyamides, and polyurethanes. This study systematically investigated the catalytic oxidation of 5-hydroxymethylfurfural (HMF) to FDCA over Pt/Al₂O₃ and Pt–Bi/Al₂O₃ catalysts. The 5Pt/Al₂O₃ catalyst yielded 60.6% FDCA after 12 h under optimized conditions (80 °C, 0.1 MPa O₂, 1 equiv. Na₂CO₃). Remarkably, Bi-modified 5Pt–1Bi/Al₂O₃ catalyst dramatically enhanced catalytic performance, achieving 94.1% FDCA yield within 6 h under optimized conditions (80 °C, 1.5 MPa O₂, 2 equiv. Na₂CO₃). Comprehensive characterization revealed that the exceptional activity originates from Bi–O–Pt interactions that modulate the electronic structure and oxidation state of Pt active sites, which facilitates the oxidation of intermediate 5-formyl-2-furancarboxylic acid (FFCA) to FDCA, the rate-limiting step of HMF oxidation. This work demonstrates an efficient Bi-promoted Pt catalytic system for FDCA production with significant potential for industrial application. Full article

(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)

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15 pages, 4745 KB

Open AccessEditor’s ChoiceArticle

Development and Kinetic Study of Novel Denitrification Catalysts Based on C₃H₆ Reductant

by Zhonghua Tang, Jingshu Ning, Xingyu Liu, Xingyu Liu, Shugang Xie, Junqiang Liu, Xin Pu, Bo Yu, Li Yang and Fang Liu

Catalysts 2025, 15(11), 1087; https://doi.org/10.3390/catal15111087 - 17 Nov 2025

Viewed by 794

Abstract

With the acceleration of industrialization, the demand for NO_x abatement is becoming increasingly urgent. Finding safer and more stable reducing agent replacements and efficient catalysts is crucial for selective catalytic reduction (SCR) industrial NO_x abatement. Low-temperature hydrocarbon-assisted NO_x reduction (HC-SCR) [...] Read more.

With the acceleration of industrialization, the demand for NO_x abatement is becoming increasingly urgent. Finding safer and more stable reducing agent replacements and efficient catalysts is crucial for selective catalytic reduction (SCR) industrial NO_x abatement. Low-temperature hydrocarbon-assisted NO_x reduction (HC-SCR) remains attractive for industrial abatement. A series of industrial-grade TiO₂ support catalysts modified with a bimetallic MnCe active component, represented as TiO₂-ig, was prepared by the impregnation method to test the NO conversion performance under a 200–400 °C window with C₃H₆ as a reducing agent, and the physical properties were characterized using the BET and XRF methods. Under the feed of 150 ppm NO, 150 ppm C₃H₆, and 3%O₂—the optimal composition—Mn₁₅Ce₁₀/TiO₂-ig catalyst exhibited the highest NO_x conversion of 77.3% among industrial-grade TiO₂ support catalysts, with the corresponding temperature reduced to 275 °C. Furthermore, a slight improvement in catalytic activity was observed upon changing the TiO₂ support type. The industrial-grade and nano-sized TiO₂ supports predominantly exhibited mesoporous structures, while the anatase TiO₂ support contained a greater proportion of macropores. A steady-state kinetic model constructed for Mn₁₅Ce₁₀/TiO₂-ig catalyst indicates that the NO reaction rate is independent of C₃H₆ and O₂ concentrations at 200 and 250 °C. At 300 °C, C₃H₆ inhibits the reaction, while both O₂ and NO promote it. Changes in activation energy and the pre-exponential factor suggest a mechanistic shift from adsorption-limited at lower temperatures to reaction-limited at higher temperatures. Overall, using industrial-grade TiO₂ with MnCe promoters delivers meaningful NO_x reduction in a low-temperature regime and provides kinetic insights relevant to process design for industrial C₃H₆-SCR. Full article

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22 pages, 3092 KB

Open AccessEditor’s ChoiceArticle

Catalytic Co-Pyrolysis of Chinese Oil Shales for Enhanced Shale Oil Yield and Quality: A Kinetic and Experimental Study

by Yang Meng, Feng Xu, Jiayong Feng, Hang Xiao and Chengheng Pang

Catalysts 2025, 15(11), 1076; https://doi.org/10.3390/catal15111076 - 13 Nov 2025

Viewed by 743

Abstract

In response to the urgent need for sustainable energy solutions and efficient fossil resource utilization, the current research is conducted to examine the catalytic co-pyrolysis of four typical Chinese oil shales. The study assesses the ability of synergistic interactions, which are the result [...] Read more.

In response to the urgent need for sustainable energy solutions and efficient fossil resource utilization, the current research is conducted to examine the catalytic co-pyrolysis of four typical Chinese oil shales. The study assesses the ability of synergistic interactions, which are the result of organic and inorganic components, to improve the aspect of thermal behavior, decrease the activation energy and improve the shale oil quality. Thermogravimetric analysis in conjunction as Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS) and integral master-plots approaches showed that there were low activation energies and better reaction kinetics in blended systems. Fischer assay and GC-MS were utilized in product distribution and product composition evaluation, respectively. Optimization increased gas yield and oil composition stabilization in the blended gas, which is found due to the catalytic functions of AAEMs and clay minerals. This contribution facilitates the development of catalytic co-processing solutions where better conversion and reduced carbon intensity are achieved in the production of fossil-based energy. Full article

(This article belongs to the Special Issue Catalytic Conversion of Small Molecules for Energy and Environmental Sustainability)

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17 pages, 1575 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Alkylation of Benzene with Benzyl Chloride: Comparative Study Between Commercial MOFs and Metal Chloride Catalysts

by Raquel Peláez, Inés Gutiérrez, Eva Díaz and Salvador Ordóñez

Catalysts 2025, 15(11), 1075; https://doi.org/10.3390/catal15111075 - 13 Nov 2025

Viewed by 896

Abstract

Diphenylmethane, recently recognized as a candidate for liquid organic hydrogen carrier systems, is traditionally produced by alkylation of benzene with benzyl chloride using homogeneous catalysts. In the current context, the need for a transition toward processes that reduce environmental impact and move toward [...] Read more.

Diphenylmethane, recently recognized as a candidate for liquid organic hydrogen carrier systems, is traditionally produced by alkylation of benzene with benzyl chloride using homogeneous catalysts. In the current context, the need for a transition toward processes that reduce environmental impact and move toward sustainability has become increasingly evident. In this work, the benzylation of benzene by benzyl chloride using metal–organic frameworks (MOFs) as catalysts is proposed, as alternative materials that combine the advantages of homogeneous and heterogeneous catalysis. Reaction experiments were carried out in an isothermal batch reactor with commercial Basolite C300 and Basolite F300 MOFs, based on Cu and Fe as active species, respectively. The results demonstrate catalytic activity using both proposed catalysts under the studied conditions, with the results of the Fe-based MOF being more favorable, given the greater standard reduction potential of Fe. Compared with their corresponding metal chlorides, the proposed MOFs improve the alkylation activity. Based on a two-step reaction mechanism, a pseudo first-order kinetic model has been developed for the reaction with MOFs as catalysts. The kinetic parameters were obtained by fitting the model to the experimental data, demonstrating good agreement and validating the proposed mechanistic pathway. Full article

(This article belongs to the Collection Catalytic Conversion and Utilization of Carbon-Based Energy)

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21 pages, 4253 KB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Progress of Low Pt Content Intermetallic Electrocatalysts Toward Proton Exchange Membrane Fuel Cells

by Huiyuan Liu, Qian Song, Yan Xie, Weiqi Zhang, Qian Xu and Huaneng Su

Catalysts 2025, 15(11), 1070; https://doi.org/10.3390/catal15111070 - 11 Nov 2025

Viewed by 1033

Abstract

Proton exchange membrane fuel cells are playing a crucial role in the widespread adoption of hydrogen energy. However, their large-scale commercialization has been hampered by the high cost and limited durability of Pt-based electrocatalysts. To overcome the issues, researchers are focusing on Pt-non-noble [...] Read more.

Proton exchange membrane fuel cells are playing a crucial role in the widespread adoption of hydrogen energy. However, their large-scale commercialization has been hampered by the high cost and limited durability of Pt-based electrocatalysts. To overcome the issues, researchers are focusing on Pt-non-noble metal (PtM) intermetallic electrocatalysts due to their superior activity and durability. This review highlights key advances in this field, starting with a comparison of intermetallic compounds and solid-solution alloys, and an analysis of the composition and structure of PtM intermetallics. It then proceeds to the controllable synthesis and structure characterization of the carbon-supported PtM intermetallics electrocatalysts. The review also thoroughly discusses their activity and durability for the oxygen reduction reaction (ORR). Finally, some perspectives on remaining challenges and future development of the PtM intermetallics electrocatalysts are presented to guide the exploitation of the active and durable intermetallic electrocatalysts with high metal content and small size for practical substitution. Full article

(This article belongs to the Special Issue Catalytic Materials in Electrochemical and Fuel Cells)

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11 pages, 1577 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Ce³⁺/Ce⁴⁺-Modified TiO₂ Nanoflowers: Boosting Solar Photocatalytic Efficiency

by Beatrice Polido, Letizia Liccardo, Benedetta Cattaneo, Enrique Rodríguez-Castellón, Alberto Vomiero and Elisa Moretti

Catalysts 2025, 15(11), 1069; https://doi.org/10.3390/catal15111069 - 11 Nov 2025

Viewed by 750

Abstract

Cerium-doped titania nanoflowers are obtained by hydrothermal synthesis, with different amounts of cerium (0.3, 0.5, and 1.0 at%). Both undoped nanoflowers (TNF) and Ce-doped TNF (Cex) are tested as photocatalysts in the degradation of the target pollutant (metronidazole) under simulated solar [...] Read more.

Cerium-doped titania nanoflowers are obtained by hydrothermal synthesis, with different amounts of cerium (0.3, 0.5, and 1.0 at%). Both undoped nanoflowers (TNF) and Ce-doped TNF (Cex) are tested as photocatalysts in the degradation of the target pollutant (metronidazole) under simulated solar light. The samples are rutile polymorphs with high crystallinity and present a nanoflower-like morphology of about 1 µm in diameter and are made up of nanoscale petals (in the range of 100–300 nm). EDX spectroscopy was coupled with SEM and performed on the Ce-doped samples to determine the elemental composition of the catalysts and the Ce distribution in each sample. Optical and electronic spectroscopies reveal that Ce loading narrows the band gap from 3.0 to 2.8 eV, extending light absorption into the visible range of the spectrum and thus enhancing the photocatalytic activity. The best sample, Ce1, achieved 67% degradation of metronidazole after 360 min under solar irradiation at pH 4, compared to bare TNF, which reached 35%. Reusability tests confirm the chemical stability and photocatalytic efficiency of Ce1 over three cycles, and free-radical trapping experiments confirmed ·O₂⁻ and ·OH as major active species in metronidazole degradation. This study highlights the synergistic impact of morphology and doping on solar-driven organic pollutant degradation. Full article

(This article belongs to the Section Catalytic Materials)

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41 pages, 15950 KB

Open AccessFeature PaperEditor’s ChoiceReview

Recent Breakthroughs in Overcoming the Efficiency Limits of Photocatalysis for Hydrogen Generation

by Aira Amin, Ryun Na Kim, Jihun Kim and Whi Dong Kim

Catalysts 2025, 15(11), 1067; https://doi.org/10.3390/catal15111067 - 10 Nov 2025

Cited by 2 | Viewed by 2870

Abstract

For five decades, photocatalysis has promised clean hydrogen from solar energy, yet a persistent “efficiency ceiling”, linked to fundamental challenges including the trade-off between light absorption and redox potential in single-component materials, has hindered its practical application. This review illuminates three key paradigm [...] Read more.

For five decades, photocatalysis has promised clean hydrogen from solar energy, yet a persistent “efficiency ceiling”, linked to fundamental challenges including the trade-off between light absorption and redox potential in single-component materials, has hindered its practical application. This review illuminates three key paradigm shifts overcoming this challenge. First, we examine Z-scheme and S-scheme heterojunctions, which resolve the bandgap dilemma by spatially separating redox sites to achieve both broad light absorption and strong redox power. Second, we discuss replacing the sluggish oxygen evolution reaction (OER) with value-added organic oxidations. This strategy bypasses kinetic bottlenecks and improves economic viability by co-producing valuable chemicals from feedstocks like biomass and plastic waste. Third, we explore manipulating the reaction environment, where synergistic photothermal effects and concentrated sunlight can dramatically enhance kinetics and unlock markedly enhanced solar-to-hydrogen (STH) efficiencies. Collectively, these strategies chart a clear course to overcome historical limitations and realize photocatalysis as an impactful technology for a sustainable energy future. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanostructured Catalysts, 3rd Edition)

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38 pages, 4591 KB

Open AccessFeature PaperEditor’s ChoiceReview

Non-Metallic Doping of Multinary Metal Oxide Semiconductors for Energy Applications

by Zhihua Wu, Jing Gao and Yongbo Kuang

Catalysts 2025, 15(11), 1062; https://doi.org/10.3390/catal15111062 - 7 Nov 2025

Viewed by 1429

Abstract

Multinary metal oxides are widely applied in energy storage and conversion, heterogeneous catalysis and environmental technologies, but their wide band gaps, low intrinsic electronic conductivity and limited density of active sites severely restrict their practical efficiency. This review examines non-metallic doping via the [...] Read more.

Multinary metal oxides are widely applied in energy storage and conversion, heterogeneous catalysis and environmental technologies, but their wide band gaps, low intrinsic electronic conductivity and limited density of active sites severely restrict their practical efficiency. This review examines non-metallic doping via the substitutional, interstitial or mixed incorporation of light elements such as B, C, N, F, P and S as a versatile strategy to overcome these fundamental limitations. We begin by outlining the primary synthesis methodologies for doped oxides, such as sol–gel, chemical vapor deposition, and hydrothermal routes, followed by a critical discussion of the multi-technique characterization framework required to verify successful dopant incorporation and elucidate its structural and electronic consequences. We focus on the fundamental principles of how doping parameters—such as mode, element type, and concentration—can be tuned to regulate material properties. The key mechanisms for performance enhancement, including synergistic lattice reconstruction, defect engineering, and electronic structure modulation, are emphasized. Significant advancements are highlighted in applications like energy storage, fuel cells, water splitting, and CO₂ reduction. Finally, we assess current challenges, such as the precise control of doping sites and long-term stability, and offer perspectives on the rational design of next-generation oxide materials. Full article

(This article belongs to the Special Issue Advanced Metal Oxide Semiconductors for Photocatalytic and Photoelectrocatalytic Solar Energy Conversion)

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14 pages, 1314 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Degradation of Atrazine to Cyanuric Acid by an Encapsulated Enzyme Cascade

by Maya Mowery-Evans, Emma Benzie, Noha Alansari, Michael Melville, Dylan Domaille and Richard C. Holz

Catalysts 2025, 15(11), 1055; https://doi.org/10.3390/catal15111055 - 5 Nov 2025

Cited by 1 | Viewed by 1017

Abstract

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine CAS: 1912-24-9) is a widely used herbicide that has been connected to a variety of negative human health and environmental effects. Various bacterial strains utilize a six-step enzyme cascade to fully degrade atrazine. The third step in this pathway, N-isopropylammelide aminohydrolase [...] Read more.

Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine CAS: 1912-24-9) is a widely used herbicide that has been connected to a variety of negative human health and environmental effects. Various bacterial strains utilize a six-step enzyme cascade to fully degrade atrazine. The third step in this pathway, N-isopropylammelide aminohydrolase (AtzC), produces the first non-toxic intermediate, cyanuric acid. As such, AtzC, paired with enzymes catalyzing the first two steps in this pathway, triazine hydrolase (TrzN) and hydroxyatrazine (2-(N-ethylamino)-4-hydroxy-6-(N-isopropylamino)-1,3,5-triazine) N-ethylaminohydrolase (AtzB), can effectively degrade atrazine. All three of these enzymes were successfully encapsulated in tetramethyl orthosilicate (TMOS) gels using the sol–gel method, producing active biomaterials. These materials showed increased protection against proteolytic digestion by the endopeptidase trypsin, as well as increased thermal and pH stability when compared to their non-encapsulated counterparts. AtzB:sol and AtzC:sol also showed increased stability over time compared to soluble enzyme. A combination of all three biomaterials, TrzN:sol, AtzB:sol, and AtzC:sol, was shown to be effective at fully degrading 50 µM atrazine to cyanuric acid in just over an hour and a half, thus establishing a potential bioremediation enzyme cascade for atrazine. Full article

(This article belongs to the Special Issue Advances in Enzymes for Industrial Biocatalysis)

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18 pages, 2496 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Impact of Macroporosity on the Transesterification of Triglycerides over MgO/SBA-15

by Thomas A. Bryant, Lois Damptey, Mark A. Isaacs, Christopher M. A. Parlett, Lee J. Durndell, Marta Granollers Mesa, Georgios Kyriakou, Karen Wilson and Adam F. Lee

Catalysts 2025, 15(11), 1054; https://doi.org/10.3390/catal15111054 - 4 Nov 2025

Viewed by 1089

Abstract

Biofuels are critical drop-in replacement energy sources to support the decarbonisation of hard-to-abate sectors such as aviation and marine shipping. Transesterification of non-edible oils is a well-established route to biodiesel as a versatile liquid transport fuel, but is challenging to scale using existing [...] Read more.

Biofuels are critical drop-in replacement energy sources to support the decarbonisation of hard-to-abate sectors such as aviation and marine shipping. Transesterification of non-edible oils is a well-established route to biodiesel as a versatile liquid transport fuel, but is challenging to scale using existing homogeneous liquid base catalysts. In this work, we report the synthesis, characterisation, and application of silica-supported MgO solid base catalysts for triglyceride transesterification with methanol and highlight the impact of silica pore structure on performance. True liquid crystal templating enables the one-pot synthesis of mesoporous MgO/SBA-15 catalysts with variable Mg content, or hierarchical macroporous–mesoporous MgO/SBA-15 analogues through the addition of polystyrene nanospheres. Both MgO/SBA-15 families exhibit highly ordered pore networks; however, ~280 nm macropores stabilise Mg-O-Si interfacial species even at high Mg loading, in contrast to the mesoporous support that permits sintering of ~14 nm MgO nanocrystals. Hierarchical porous MgO/SBA-15 catalysts exhibit higher specific activity and conversion of tributyrin to methyl butyrate than their mesoporous analogues (3 mmol⋅h⁻¹⋅g⁻¹ versus 2 mmol⋅h⁻¹⋅g⁻¹ at 60 °C and 11 wt% Mg). The magnitude of this rate enhancement increases with triglyceride chain length, being approximately three-fold for trilaurin (C₁₂) transesterification at 90 °C, attributed to superior in-pore mass transport of bulky reactants through the hierarchical porous catalyst. Full article

(This article belongs to the Section Nanostructured Catalysts)

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15 pages, 2177 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Platinum Nanoparticles Supported on Atomic Layer Deposited SnO₂ Decorated Multiwalled Carbon Nanotubes as the Electrocatalyst for the Oxygen Reduction Reaction

by Raegan Chambers, Aivar Tarre, Markus Otsus, Jekaterina Kozlova, Kaupo Kukli, Arvo Kikas, Vambola Kisand, Heiki Erikson and Kaido Tammeveski

Catalysts 2025, 15(11), 1052; https://doi.org/10.3390/catal15111052 - 4 Nov 2025

Viewed by 930

Abstract

Tin(IV) oxide (SnO₂) was deposited onto acid-washed multiwalled carbon nanotubes (MWCNTs) to be used as a support for platinum nanoparticles (PtNPs). The effect of the SnO₂–CNT support on the electrocatalytic activity of the PtNPs for the oxygen reduction reaction [...] Read more.

Tin(IV) oxide (SnO₂) was deposited onto acid-washed multiwalled carbon nanotubes (MWCNTs) to be used as a support for platinum nanoparticles (PtNPs). The effect of the SnO₂–CNT support on the electrocatalytic activity of the PtNPs for the oxygen reduction reaction (ORR) in 0.1 M HClO₄ solution was investigated. The physical characterization of the catalyst confirms the presence of Pt, Sn and C on the catalyst as well as the presence of the PtNPs on SnO₂. The synthesized catalyst possesses a specific activity of 0.15 mA cm⁻² at 0.9 V, while the commercial Pt/C catalyst showed a specific activity of 0.05 mA cm⁻². Accelerated durability testing (ADT) was performed on both catalysts, with the synthesized PtNP/SnO₂–CNT catalyst retaining over 50% of its initial electrochemically active surface area (ECSA). Thus, the results obtained in this study confirm the positive influence of SnO₂-decorated CNTs on the overall electrocatalytic activity of PtNPs and their stability toward the ORR. Full article

(This article belongs to the Special Issue Catalysis by Metals and Metal Oxides)

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27 pages, 3114 KB

Open AccessEditor’s ChoiceReview

Carbon Nitride-Based Catalysts for Photocatalytic NO Removal

by Sheng Wang, Fu Chen, Xiyao Niu and Huagen Liang

Catalysts 2025, 15(11), 1043; https://doi.org/10.3390/catal15111043 - 3 Nov 2025

Viewed by 1132

Abstract

Nitrogen oxides (NO_x) are major atmospheric pollutants, and their escalating emissions, driven by rapid economic development and urbanization, pose a severe threat to both the ecological environment and human health. Conventional denitrification technologies are often hampered by high costs, significant energy [...] Read more.

Nitrogen oxides (NO_x) are major atmospheric pollutants, and their escalating emissions, driven by rapid economic development and urbanization, pose a severe threat to both the ecological environment and human health. Conventional denitrification technologies are often hampered by high costs, significant energy consumption, and stringent operational conditions, making them increasingly inadequate in the face of tightening environmental regulations. In this context, photocatalytic technology, particularly systems based on graphitic carbon nitride (g-C₃N₄), has garnered significant research interest for NO_x removal due to its visible-light responsiveness, high stability, and environmental benignity. To advance the performance of g-C₃N₄, numerous modification strategies have been explored, including morphology control, elemental doping, defect engineering, and heterostructure construction. These approaches effectively broaden the light absorption range, enhance the separation efficiency of photogenerated electron-hole pairs, and improve the adsorption and conversion capacities for NO_x. Notably, constructing heterojunctions between g-C₃N₄ and other materials (e.g., metal oxides, noble metals, metal–organic frameworks (MOFs)) has proven highly effective in boosting catalytic activity and stability. Furthermore, the underlying photocatalytic mechanisms, encompassing the generation and migration pathways of charge carriers, the redox reaction pathways of NO_x, and the influence of external factors like light intensity and reaction temperature, have been extensively investigated. From an application perspective, g-C₃N₄-based photocatalysis demonstrates considerable potential in flue gas denitrification, vehicle exhaust purification, and air purification. Despite these advancements, several challenges remain, such as limited solar energy utilization, rapid charge carrier recombination, and insufficient long-term stability, which hinder large-scale implementation. Future research should focus on further optimizing the material structure, developing greener synthesis routes, enhancing catalyst stability and poison resistance, and advancing cost-effective engineering applications to facilitate the practical deployment of g-C₃N₄-based photocatalytic technology in air pollution control. Full article

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20 pages, 4353 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Synthesis of MOF-Derived Mono-, Bi- and Trimetallic Fe, Zn and Cu Oxides for Microwave-Assisted Benzyl Alcohol Oxidation

by Carmen Moreno-Fernández, Marina Ronda-Leal, Antonio Ángel Romero and Antonio Pineda

Catalysts 2025, 15(11), 1050; https://doi.org/10.3390/catal15111050 - 3 Nov 2025

Viewed by 1139

Abstract

The increasing demand for sustainable chemical processes has fostered the development of advanced catalytic systems for biomass valorization. In this work, a series of mono-, bi-, and trimetallic oxides (FeO, FeCuO, FeZnO, and FeCuZnO) were successfully synthesized using MIL-101-based MOFs as sacrificial templates. [...] Read more.

The increasing demand for sustainable chemical processes has fostered the development of advanced catalytic systems for biomass valorization. In this work, a series of mono-, bi-, and trimetallic oxides (FeO, FeCuO, FeZnO, and FeCuZnO) were successfully synthesized using MIL-101-based MOFs as sacrificial templates. The obtained materials were thoroughly characterized by N₂ adsorption–desorption, XRD, FTIR, and TEM/STEM-EDX to investigate their structural, morphological, and textural properties. Their catalytic performance was evaluated in the selective oxidation of benzyl alcohol, a lignin-derived platform molecule, into benzaldehyde under microwave irradiation as a sustainable heating strategy. The results demonstrate that MOF-derived oxides exhibit superior activity compared to their parent MOFs, highlighting the beneficial effect of thermal treatment on the exposure of active sites. Among the catalysts, heterometallic oxides showed enhanced performance due to synergistic effects between metals. In particular, FeZnO reached a maximum yield of 62.1% towards benzaldehyde at 150 °C and 30 min, outperforming the monometallic oxide. Recycling tests revealed that FeZnO retained higher overall performance than FeCuO, which suffered from progressive copper leaching. These findings confirm the potential of MOF-derived multimetallic oxides as efficient and reusable heterogeneous catalysts for selective biomass-derived alcohol oxidation. The combination of microwave-assisted processes and the tuneable nature of MOF-derived oxides provides a promising pathway for designing sustainable catalytic systems with industrial relevance. Full article

(This article belongs to the Special Issue Advances in Microwave-Assisted Catalysis: From Catalytic Materials to Catalytic Reactions)

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19 pages, 3963 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Safety and Process Intensification of Catalytic Reduction of 4-Nitophenol Using Sodium Borohydride in Flow Microreactor System

by Ahmed Ibrahim Elhadad and Magdalena Luty-Błocho

Catalysts 2025, 15(11), 1038; https://doi.org/10.3390/catal15111038 - 2 Nov 2025

Viewed by 1019

Abstract

In this work, a novel approach for the catalytic reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride is proposed. It was shown that a continuous-flow microreactor system is an optimal tool for PdNP synthesis with dimensions of 3.0 ± 0.5 nm, as well [...] Read more.

In this work, a novel approach for the catalytic reduction of 4-nitrophenol to 4-aminophenol using sodium borohydride is proposed. It was shown that a continuous-flow microreactor system is an optimal tool for PdNP synthesis with dimensions of 3.0 ± 0.5 nm, as well as the performance of catalytic tests with high process efficiency, while keeping a high level of safety. The results obtained from the microreactor system allowed for 100% conversion to 4-aminophenol and were compared to processes carried out in a batch reactor, as well as to a hybrid system which was a combination of a microreactor (synthesis of PdNPs) and batch reactor (catalytic test). These investigations were enhanced by kinetic studies, for which a stopped-flow spectrophotometer was applied due to the extremely high rate of the reaction, i.e., formation of PdNPs (2.1 s), as well as to measure in situ the rate of the heterogeneous catalytic process. To visualize the progress of the heterogeneous reaction more precisely, color coding based on transmittance measurements was employed. Furthermore, to deepen the understanding of the process, a detailed mechanism supported by DFT calculations for the conversion of 4-nitrophenol to 4-aminophenol in the presence of PdNPs was proposed. Full article

(This article belongs to the Special Issue Catalytic Conversion of Small Molecules for Energy and Environmental Sustainability)

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15 pages, 2832 KB

Open AccessEditor’s ChoiceArticle

Halloysite@Polydopamine Nanoplatform for Ultrasmall Pd and Cu Nanoparticles: Suitable Catalysts for Hydrogenation and Reduction Reactions

by Marina Massaro, Chiara D’Acunzi, Stefano Paganelli, Maria Laura Alfieri, Leonarda F. Liotta, Alberto Lopez-Galindo, Raquel de Melo Barbosa, Oreste Piccolo, Rita Sánchez-Espejo, César Viseras and Serena Riela

Catalysts 2025, 15(11), 1029; https://doi.org/10.3390/catal15111029 - 1 Nov 2025

Cited by 1 | Viewed by 784

Abstract

The design of sustainable nanomaterials for catalysis is a key challenge in green chemistry. Herein, we report the synthesis of halloysite nanotube (Hal)-based nanomaterials selectively functionalized with a bio-inspired polydopamine (PDA) coating, which enables the controlled anchoring of palladium and copper nanoparticles (PdNPs [...] Read more.

The design of sustainable nanomaterials for catalysis is a key challenge in green chemistry. Herein, we report the synthesis of halloysite nanotube (Hal)-based nanomaterials selectively functionalized with a bio-inspired polydopamine (PDA) coating, which enables the controlled anchoring of palladium and copper nanoparticles (PdNPs and CuNPs). This mild and ecofriendly strategy yields highly dispersed and ultrasmall (<5 nm) metal nanoparticles without the need for surfactants or harsh reagents. The resulting materials, Hal@PDA/PdNPs and Hal@PDA/CuNPs, were evaluated in two well-established model reactions commonly employed to probe catalytic performance: cinnamaldehyde hydrogenation and 4-nitrophenol reduction. Hal@PDA/PdNPs displayed complete conversion and >90% selectivity toward hydrocinnamaldehyde at low Pd loading (0.8 wt%) and maintained its efficiency over six catalytic cycles (TOF up to 0.1 s⁻¹), while Hal@PDA/CuNPs retained high activity through eight consecutive runs in the reduction of 4-nitrophenol. Hal@PDA/CuNPs proved to be an excellent recyclable catalyst for the reduction of 4-nitrophenol, retaining high activity through eight consecutive runs. Overall, this study introduces a robust and modular approach to fabricating halloysite-based nanocatalysts, demonstrating their potential as green platforms for metal nanoparticle-mediated transformation. Full article

(This article belongs to the Special Issue 15th Anniversary of Catalysts: Shaping a Sustainable Future Through Catalysis)

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15 pages, 3008 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Effects of Zn Doping on the Morphology and H₂ Production Activity of Truncated Octahedral Cu₂O Photocatalysts

by Arul Pundi, Chun-Wen Kang and Chi-Jung Chang

Catalysts 2025, 15(11), 1030; https://doi.org/10.3390/catal15111030 - 1 Nov 2025

Viewed by 773

Abstract

The truncated octagonal cuprous oxide photocatalysts were synthesized in the presence of polyvinylpyrrolidone. Zn-doped Cu₂O photocatalysts were successfully synthesized with different ZnSO₄/CuSO₄ ratios. The effects of Zn doping on the light absorption, morphology, separation of photogenerated charge carriers, [...] Read more.

The truncated octagonal cuprous oxide photocatalysts were synthesized in the presence of polyvinylpyrrolidone. Zn-doped Cu₂O photocatalysts were successfully synthesized with different ZnSO₄/CuSO₄ ratios. The effects of Zn doping on the light absorption, morphology, separation of photogenerated charge carriers, and hydrogen production performance of the photocatalyst were investigated. The size and morphology of the Zn-doped Cu₂O-based nanomaterials change with increasing dosages of zinc sulfate dopant. Zn doping resulted in a reduction in crystallite size, a change in morphology, and a decrease in the size of the nanomaterial. The hydrogen production activity of the Zn-Cu₂O photocatalyst Zn-Cu₂O-2 with optimized dopant content can reach 9690 μmol h⁻¹g⁻¹. The enhanced photocatalytic activity of Zn-doped Cu₂O photocatalyst is achieved through significantly improved electron-hole separation, which is maximized at an optimal Zn dopant concentration. Full article

(This article belongs to the Collection Nanotechnology in Catalysis)

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15 pages, 2908 KB

Open AccessEditor’s ChoiceArticle

Production of Syngas and Hydrogen-Rich Gas from Lignocellulosic Biomass via Ru/Al₂O₃ Catalyst-Assisted Slow Pyrolysis

by Pavel Straka, Jaroslav Cihlář and Olga Bičáková

Catalysts 2025, 15(11), 1033; https://doi.org/10.3390/catal15111033 - 1 Nov 2025

Viewed by 976

Abstract

The aim of this work is to present a technologically feasible method for processing biomass into synthesis gas or hydrogen-rich gas. Three types of biomass with different lignin contents were pyrolyzed in a pyrolysis unit under well-defined conditions (ambient pressure, heating rate of [...] Read more.

The aim of this work is to present a technologically feasible method for processing biomass into synthesis gas or hydrogen-rich gas. Three types of biomass with different lignin contents were pyrolyzed in a pyrolysis unit under well-defined conditions (ambient pressure, heating rate of 10 K min⁻¹, end temperature of 500 °C, operating particle size, variable catalyst mass) in the presence of a ruthenium catalyst (Ru/Al₂O₃, powder), and the effect of catalyst amount on the yield and gas composition was observed. Feedstock mass was always 50 g, and catalyst mass was 2.5, 5, and 10 g (mixing ratios 0.05, 0.1, and 0.2, resp.). During pyrolysis, the raw gas and vapors was passed through the catalyst bed and converted to the resulting gas and bio-oil. The gas obtained was cleaned by sequestration with CO₂ using commercial active carbon to obtain syngas with different H₂/CO ratios or hydrogen-rich gas. It was found that, depending on the catalyst amount, slow pyrolysis catalyzed by ruthenium yielded syngas with a H₂/CO ratio of approximately 0.5–5, which is further usable. The by-products obtained (bio-oil and biochar) are also described. Bio-oils from all three biomass types contained mainly carboxylic acids (33–46 wt.%) and phenols (18–33 wt.%), hydroquinone (up to 5 wt.%), and a high amount of stearate (up to 26 wt.%). All of these compounds have high utility value. The resulting biochar can probably be applied, after activation using CO₂, as a sorbent. In conclusion, under energy-efficient conditions (end temperature max. 500 °C), Ru/Al₂O₃-catalyzed pyrolysis of biomass provides syngas or hydrogen-rich gas and usable by-products. It should be emphasized that the maximum theoretical H₂ production from biomass is 60–70 g H₂/kg biomass. This limit value could negatively affect the technological development of the process. Full article

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35 pages, 3095 KB

Open AccessFeature PaperEditor’s ChoiceReview

Biomass Conversion to Value-Added Chemicals and Fuels Using Natural Minerals as Catalysts or Catalytic Supports

by Sotiris Lycourghiotis and Eleana Kordouli

Catalysts 2025, 15(11), 1006; https://doi.org/10.3390/catal15111006 - 23 Oct 2025

Cited by 1 | Viewed by 2472

Abstract

Biofuels and value-added chemicals can be produced using biomass. These products can substitute the corresponding petroleum-based ones, reducing the carbon footprint, ensuring domestic production, and minimizing/exploiting organic wastes in a circular economy philosophy. Natural mineral-based catalysts seem to be a promising, eco-friendly, and [...] Read more.

Biofuels and value-added chemicals can be produced using biomass. These products can substitute the corresponding petroleum-based ones, reducing the carbon footprint, ensuring domestic production, and minimizing/exploiting organic wastes in a circular economy philosophy. Natural mineral-based catalysts seem to be a promising, eco-friendly, and low-cost approach for biomass valorization. This article attempts to highlight the potential of natural mineral-based catalysts for various processes targeting the above valorization. Natural zeolites and clays can be used as catalysts/CO₂ adsorbents and catalytic supports in various biorefinery processes (pyrolysis, gasification, hydrothermal liquefaction, esterification/transesterification, hydrotreatment, cracking, isomerization, oxidation, condensation, etc.). Acid/base, redox, and textural properties of these materials are key factors for their catalytic performance and can be easily regulated by suitable treatments, like calcination, acid/base-washing, metal impregnation, doping, etc., which are discussed in this article. The application of natural minerals in biorefinery processes makes them greener, cost-effective, and easily scalable. Full article

(This article belongs to the Special Issue Advanced Catalysts for Biomass Pyrolysis)

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15 pages, 12491 KB

Open AccessEditor’s ChoiceArticle

Effects of Sodium-to-OSDA Ratio in the Synthesis Gel on SSZ-39 Formation and Material Properties

by Zheng Cui, Charles E. Umhey, Daniel F. Shantz and Jean-Sabin McEwen

Catalysts 2025, 15(10), 989; https://doi.org/10.3390/catal15100989 - 16 Oct 2025

Viewed by 770

Abstract

This work quantifies how varying the Na/OSDA ratio in the synthesis gel (at fixed total [OH] content) affects the formation of SSZ-39, its growth kinetics, and the composition of the products obtained. It was found that it is possible to make phase-pure SSZ-39 [...] Read more.

This work quantifies how varying the Na/OSDA ratio in the synthesis gel (at fixed total [OH] content) affects the formation of SSZ-39, its growth kinetics, and the composition of the products obtained. It was found that it is possible to make phase-pure SSZ-39 with Si/Al ratios varying from 6.3 to 10.7 with Na/OSDA ratios from 9.1 to 1.7 in the synthesis gel. Higher Na/OSDA ratios lead to faster crystallization, supporting the hypothesis that FAU dissolution is the rate-limiting step in SSZ-39 synthesis when FAU serves as the aluminum source. DFT modeling suggests that, in the presence of OSDA molecules, increased Na content lowers the energy penalty for placing Al atoms in close proximity, which may explain why higher NaOH/OSDA ratios experimentally yield lower Si:Al ratios. This work offers another way to control the framework composition and potentially impact the local structure of the SSZ-39 that is obtained. Cobalt titration was performed to probe the presence of so-called aluminum pairs in samples made with different Na/OSDA ratios. The cobalt uptake in the H-form products is consistently low and suggests that factors other than aluminum pairing, such as solution pH, could be important in influencing the cobalt uptake. Full article

(This article belongs to the Special Issue Predictive Modeling in Catalysis)

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15 pages, 8110 KB

Open AccessEditor’s ChoiceArticle

Enabling Coal-Fired Power Flexibility: Wide-Temperature NOx Removal via Strong Electron–Orbital Interaction in Dual-Site Catalysts

by Shaogang Wang, Pengxin Zeng, Ning Li, Yuansheng Yi, Yongsheng Qin, Xin Yu, Lei Liu, Qi Guo and Zijian Zhou

Catalysts 2025, 15(10), 971; https://doi.org/10.3390/catal15100971 - 11 Oct 2025

Viewed by 697

Abstract

The narrow operating temperature window of commercial V-W/TiO₂ catalysts severely limits NO_x removal efficiency, especially during low-load boiler operations. To achieve broad-temperature NO_x abatement, we developed Ce-M/Ti (M = Co, Fe, Mn, Mo) catalysts via a dual-site strategy. The temperatures [...] Read more.

The narrow operating temperature window of commercial V-W/TiO₂ catalysts severely limits NO_x removal efficiency, especially during low-load boiler operations. To achieve broad-temperature NO_x abatement, we developed Ce-M/Ti (M = Co, Fe, Mn, Mo) catalysts via a dual-site strategy. The temperatures required for 80% NO conversion (T₈₀) were 302 °C for Ce-Mo/Ti, 372 °C for Ce-Fe/Ti, 393 °C for Ce-Mn/Ti, and 415 °C for Ce-Co/Ti. Among them, Ce-Mo/Ti exhibited the most favorable low-temperature activity, outperforming a commercial catalyst (324 °C). Its turnover frequency (3.12 × 10⁻³ s⁻¹) was 1.29 times higher. Combined physicochemical characterization and density functional theory (DFT) calculations further reveal the mechanism behind the enhanced dual-site synergy in Ce-Mo/Ti. In the Ce-Co, Ce-Fe, and Ce-Mn sites, weak orbital hybridization leads to limited charge transfer. In contrast, Ce-Mo/Ti exhibits stronger hybridization between the Ce 4f/5d and Mo 4d orbitals, which breaks the inherent limitation of the Ce-based (Ce³⁺/Ce⁴⁺) redox capability and enables reverse electron transfer from Mo to Ce. This distinctive electron transfer direction creates a unique electronic environment, activating an efficient redox cycle between Mo⁶⁺/Mo⁵⁺ and Ce⁴⁺/Ce³⁺. This work offers a promising design strategy for dual-site catalysts with high NO_x removal efficiency over a wide temperature range. Full article

(This article belongs to the Special Issue Advanced Catalytic Technologies for NO_x Abatement and Environmental Sustainability)

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19 pages, 2196 KB

Open AccessEditor’s ChoiceArticle

Mechanistic Distinction Between Oxidative and Chlorination Transformations of Chloroperoxidase from Caldariomyces fumago Demonstrated by Dye Decolorization

by Norman Paz-Ramirez, Jacob Redwinski, Matthew A. Cranswick, Kyle A. Grice and Kari L. Stone

Catalysts 2025, 15(10), 965; https://doi.org/10.3390/catal15100965 - 9 Oct 2025

Viewed by 1798

Abstract

Effluents from the textile industry, particularly those containing synthetic azo dyes, poses a significant environmental threat, necessitating the development of more effective and sustainable pollutant removal methods. Traditional dye removal techniques often fall short in efficiency and environmental impact, prompting the exploration of [...] Read more.

Effluents from the textile industry, particularly those containing synthetic azo dyes, poses a significant environmental threat, necessitating the development of more effective and sustainable pollutant removal methods. Traditional dye removal techniques often fall short in efficiency and environmental impact, prompting the exploration of enzymatic degradation as a promising alternative. This study focuses on chloroperoxidase, a natural biocatalyst recognized for its ability to oxidize synthetic dyes into less harmful products. By exploring the mechanistic distinction between chlorination and oxidative processes, we investigate the enzyme’s specific degradation pathways for azo dyes and the resulting by-products. Utilizing analytical techniques, including liquid chromatography/mass spectrometry (LC/MS), and density functional theory (DFT), we gain insights into the decolorization mechanism, revealing that the enzyme preferentially generates oxidative products through C–N bond cleavage as its initial degradation step. These findings underscore not only the unique mechanistic properties of chloroperoxidase but also its potential as a biocatalyst for industrial applications. This study advocates further research into the optimization of enzyme-based systems, highlighting their relevance in advancing greener chemical practices in the textile industry, thus contributing to more sustainable manufacturing processes. Full article

(This article belongs to the Special Issue Enzyme Engineering—the Core of Biocatalysis)

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21 pages, 4159 KB

Open AccessFeature PaperEditor’s ChoiceArticle

The Key Role of Carbon Materials in the Biological and Photocatalytic Reduction of Nitrates for the Sustainable Management of Wastewaters

by Luisa M. Pastrana-Martínez, Sergio Morales-Torres and Francisco J. Maldonado-Hódar

Catalysts 2025, 15(10), 958; https://doi.org/10.3390/catal15100958 - 6 Oct 2025

Viewed by 988

Abstract

This work explores the influence of material properties and experimental conditions on both biological and photocatalytic nitrate reduction processes. For the biological route, results demonstrate that carbon supports, specifically carbon gels, with open porosity, slight acidity, and high purity enhance E. coli adhesion [...] Read more.

This work explores the influence of material properties and experimental conditions on both biological and photocatalytic nitrate reduction processes. For the biological route, results demonstrate that carbon supports, specifically carbon gels, with open porosity, slight acidity, and high purity enhance E. coli adhesion and promote the formation of highly active bacterial colonies. However, carbon supports of bacteria, produced from waste biomass, emerge as a sustainable and cost-effective alternative, improving scalability and environmental value. The complete conversion of nitrates to nitrites, followed by full nitrite reduction, is achieved under optimized conditions. Photocatalytic nitrate reduction under solar radiation is also proposed as a promising and ecofriendly upgrade method to conventional wastewater treatment. Graphene oxide (GO) was used to enhance the photocatalytic activity of TiO₂ nanoparticles for the degradation of nitrates. The efficiency of nitrate reduction is found to be highly sensitive to solution pH and the physicochemical nature of the photocatalyst surface, which governs nitrate interactions through electrostatic forces. TiO₂–GO composites achieved up to 80% nitrate removal within 1 h and complete removal of 50 mg/L nitrate within 15 min under optimized conditions. The screening of hole scavengers revealed that formic acid, in combination with the TiO₂–GO composite, delivered exceptional performance, achieving complete nitrate reduction in just 15 min under batch conditions at an acidic pH. Full article

(This article belongs to the Special Issue Advances in Photocatalytic Wastewater Purification, 2nd Edition)

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19 pages, 281 KB

Open AccessFeature PaperEditor’s ChoiceReview

Heterogeneous Catalysts from Food Waste for Biodiesel Synthesis—A Comprehensive Review

by Violeta Makarevičienė, Ieva Gaidė and Eglė Sendžikienė

Catalysts 2025, 15(10), 957; https://doi.org/10.3390/catal15100957 - 5 Oct 2025

Cited by 1 | Viewed by 2129

Abstract

The transesterification process of vegetable oil applied in biodiesel synthesis is catalytic. Industrial production uses chemical catalysts that are difficult to separate from the product, regenerate, and reuse, which is why there is a search for new catalysts that are of natural origin [...] Read more.

The transesterification process of vegetable oil applied in biodiesel synthesis is catalytic. Industrial production uses chemical catalysts that are difficult to separate from the product, regenerate, and reuse, which is why there is a search for new catalysts that are of natural origin or obtained from various types of waste. Calcium oxide is widely used as a heterogeneous catalyst, and can be obtained from calcium carbonate. The article reviews the possibilities of using eggshells as a catalyst for biodiesel synthesis: the optimal calcination conditions, the efficiency of the obtained catalyst, the optimal transesterification conditions, and the influence of various factors on biodiesel yield. It also discusses the possibilities and conditions for regenerating the catalyst and reusing it. Another food industry waste containing calcium compounds is animal bones, from which an effective biodiesel synthesis catalyst can be obtained. Before use, the bones are also crushed and calcined. The article presents the conditions for catalyst preparation and catalytic activity, and the possibilities for its enhancement by incorporating other elements, as well as the dependence of ester yields on transesterification conditions. The process of catalyst regeneration and reuse is discussed. Full article

(This article belongs to the Special Issue Applications of Catalysis in Organic Chemistry: Sustainable Catalysts for Sustainable Processes)

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11 pages, 4406 KB

Open AccessEditor’s ChoiceArticle

Rational Design of Nanosized Pt Immobilized on Biomass-Derived Porous Carbon for Enhanced Methanol Oxidation

by Xinggang Shan, Yanan Li, Wei Feng, Jinlong Qin, Xinyi Zhang, Gangqiang Wang and Haiyan He

Catalysts 2025, 15(10), 949; https://doi.org/10.3390/catal15100949 - 2 Oct 2025

Viewed by 793

Abstract

We present the rational design of nanosized Pt nanocrystals immobilized on biomass-derived porous carbon matrices (Pt/BPC) through a convenient and eco-friendly strategy using wheat flour as a sustainable precursor. Interestingly, the three-dimensional BPC conductive network with optimized pore geometry enables enhanced metal–support interaction [...] Read more.

We present the rational design of nanosized Pt nanocrystals immobilized on biomass-derived porous carbon matrices (Pt/BPC) through a convenient and eco-friendly strategy using wheat flour as a sustainable precursor. Interestingly, the three-dimensional BPC conductive network with optimized pore geometry enables enhanced metal–support interaction through d-orbital electron coupling, while the nitrogen-rich carbon scaffold provides abundant nucleation sites for the growth of ultrasmall Pt and effectively prevents them from aggregation. Accordingly, the resultant Pt/BPC catalyst demonstrates exceptional methanol oxidation performance with a large electrochemical surface area, a high mass activity of 1232.5 mA mg⁻¹, and excellent long-term stability, representing significant improvements over conventional carbon (e.g., carbon black, carbon nanotube, graphene, etc.)-supported Pt catalysts. Full article

(This article belongs to the Special Issue Surface and Interface Engineering of Catalyst Nanostructures for Electrochemical Energy Conversion)

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22 pages, 2608 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Exploring the Evolution of Co-Deposited Copper and Iron Nanostructures on Hydroxyapatite: Implications in NH₃-SCR Reaction

by Melissa Greta Galloni, Weidong Zhang, Anne Giroir-Fendler, Sebastiano Campisi and Antonella Gervasini

Catalysts 2025, 15(10), 929; https://doi.org/10.3390/catal15100929 - 1 Oct 2025

Viewed by 846

Abstract

Copper and iron species were co-deposited onto a hydroxyapatite surface to produce bimetallic catalysts. Characterization techniques (XRD, XPS, DR-UV spectroscopy and TEM-EDX) helped in unveiling the speciation, nuclearity, and electronic properties of copper and iron in samples with variable total metal loading (1–10 [...] Read more.

Copper and iron species were co-deposited onto a hydroxyapatite surface to produce bimetallic catalysts. Characterization techniques (XRD, XPS, DR-UV spectroscopy and TEM-EDX) helped in unveiling the speciation, nuclearity, and electronic properties of copper and iron in samples with variable total metal loading (1–10 wt.%) and relative Cu-to-Fe ratios. The speciation of Cu was revealed to be not affected by Fe and vice versa. Conversely, the metal loading turned out to be a key factor ruling the aggregation state of Cu and Fe species. The samples were tested as catalysts in the Selective Catalytic Reduction of NO by NH₃ (NH₃-SCR) in dry and wet environments under quasi-real conditions (50,000 ppm O₂; 50,000 ppm H₂O, if present; 120,000 h⁻¹ GHSV) in the 200−500 °C interval. Although the combination of Cu and Fe affords a modest improvement in water resistance compared to their monometallic counterparts, no substantial enhancement in activity was observed for the bimetallic hydroxyapatite-based SCR catalysts. Full article

(This article belongs to the Special Issue Advances in Transition Metal Catalysis, 2nd Edition)

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25 pages, 2942 KB

Open AccessEditor’s ChoiceReview

MOF-Derived Metal Sulfides and Their Composites: Synthesis and Their Electrochemical Water Splitting

by Zhengxin Fei, Yupeng Song, Mingyi Wu, Yifang Wu, Yingying Chen, Dae Joon Kang, Chaoqun Bian and Yongteng Qian

Catalysts 2025, 15(10), 928; https://doi.org/10.3390/catal15100928 - 1 Oct 2025

Cited by 4 | Viewed by 2144

Abstract

Owing to their tunable electronic structures, exceptional structural stability, and superior catalytic performance, metal–organic framework (MOF)-derived metal sulfides have emerged as promising candidates for use in energy conversion systems. This review first summarizes the various synthesis methods for MOF-derived metal sulfides. Subsequently, recent [...] Read more.

Owing to their tunable electronic structures, exceptional structural stability, and superior catalytic performance, metal–organic framework (MOF)-derived metal sulfides have emerged as promising candidates for use in energy conversion systems. This review first summarizes the various synthesis methods for MOF-derived metal sulfides. Subsequently, recent progress in electrochemical water splitting, including the hydrogen evolution reaction, oxygen evolution reaction, and overall water splitting are discussed. Finally, the current challenges of MOF-derived metal sulfides for electrochemical water splitting are also highlighted. We hope that this review will serve as a valuable reference for the rational design of novel MOF-derived metal sulfides for use in electrochemical water splitting. Full article

(This article belongs to the Special Issue Recent Progress in Electrocatalysis for Membrane-Driven Energy Technologies: Fuel Cells, Electrolysis, and Emerging Applications)

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14 pages, 6591 KB

Open AccessFeature PaperEditor’s ChoiceArticle

One-Step Fe/N Co-Doping for Efficient Catalytic Oxidation and Selective Non-Radical Pathway Degradation in Sludge-Based Biochar

by Zupeng Gong, Shixuan Ding, Mingjie Huang, Wen-da Oh, Xiaohui Wu and Tao Zhou

Catalysts 2025, 15(10), 934; https://doi.org/10.3390/catal15100934 - 1 Oct 2025

Viewed by 907

Abstract

This study presents the preparation of iron and nitrogen co-doped sludge-based biochar (FeCN-MSBC) and iron oxide-doped biochar (FeO-MSBC) by ball milling municipal sludge with different iron precursors (K₃Fe(CN)₆ and Fe₂O₃), followed by pyrolysis. These biochars were [...] Read more.

This study presents the preparation of iron and nitrogen co-doped sludge-based biochar (FeCN-MSBC) and iron oxide-doped biochar (FeO-MSBC) by ball milling municipal sludge with different iron precursors (K₃Fe(CN)₆ and Fe₂O₃), followed by pyrolysis. These biochars were utilized to activate persulfate (PMS) for the degradation of phenolic pollutants. The results demonstrate that FeCN-MSBC, formed by the introduction of K₃Fe(CN)₆, contains Fe/N phases, with surface Fe sites exhibiting a lower oxidation state, which significantly enhances PMS activation efficiency. In contrast, FeO-MSBC, due to the aggregation of Fe₂O₃/Fe₃O₄, shows relatively lower catalytic activity. The FeCN-MSBC/PMS system degrades pollutants via a synergistic mechanism involving non-radical pathways mediated by ¹O₂ and electron transfer processes (ETP) catalyzed by surface Fe. Electrochemical oxidation and quenching experiments confirm that ETP is the dominant pathway. FeCN-MSBC, prepared at a pyrolysis temperature of 600 °C and an Fe loading of 3 mmol/g TSS, exhibited the best performance, achieving a phenol degradation rate constant (k_obs) of 0.127 min⁻¹, 4.5 times higher than that of undoped biochar (MSBC). FeCN-MSBC/PMS maintained high efficiency across a wide pH range and in complex water matrices, exhibiting excellent stability over multiple cycles, demonstrating strong potential for practical applications. This study provides an effective strategy for simultaneous Fe and N doping in sludge-derived biochar and offers mechanistic insights into Fe/N synergistic activation of PMS for practical water treatment. Full article

(This article belongs to the Special Issue Environmentally Friendly Catalysis for Green Future)

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24 pages, 1986 KB

Open AccessEditor’s ChoiceReview

Nitrile-Converting Enzymes: Industrial Perspective, Challenges and Emerging Strategies

by Binuraj R. K. Menon, James David Philpin, Joe James Scaife and Thomas Chua

Catalysts 2025, 15(10), 939; https://doi.org/10.3390/catal15100939 - 1 Oct 2025

Viewed by 1894

Abstract

Nitrile-containing compounds are integral to pharmaceuticals, agrochemicals and polymer industries, yet their environmental persistence and toxicity pose major challenges. Biocatalytic approaches using nitrile-converting enzymes—particularly nitrilases and nitrile hydratases—offer sustainable alternatives to conventional hydrolysis, enabling the selective transformation of nitriles into amides and acids [...] Read more.

Nitrile-containing compounds are integral to pharmaceuticals, agrochemicals and polymer industries, yet their environmental persistence and toxicity pose major challenges. Biocatalytic approaches using nitrile-converting enzymes—particularly nitrilases and nitrile hydratases—offer sustainable alternatives to conventional hydrolysis, enabling the selective transformation of nitriles into amides and acids under mild conditions. This review presents an industrial perspective on nitrile-converting enzymes, summarising their catalytic potential, current limitations, and emerging strategies for stability, activity and performance enhancement. Advances in protein engineering, metagenomic discovery and biocatalytic optimisation have already expanded their wider applicability, while synthetic biology and protein design tools are accelerating the development of tailored biocatalysts. The integration of these enzymes into cascades and chemoenzymatic processes supports scalable and innovative solutions to green manufacturing. Collectively, these emerging strategies position nitrile-converting enzymes as versatile tools for sustainable catalysis, with growing relevance in fine chemical synthesis, waste remediation, and bio-based synthetic platforms. Full article

(This article belongs to the Section Biocatalysis)

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33 pages, 5967 KB

Open AccessEditor’s ChoiceReview

Metal-Organic Frameworks and Covalent Organic Frameworks for CO₂ Electrocatalytic Reduction: Research Progress and Challenges

by Yuyuan Huang, Haiyan Zhu, Yongle Wang, Guohao Yin, Shanlin Chen, Tingting Li, Chou Wu, Shaobo Jia, Jianxiao Shang, Zhequn Ren, Tianhao Ding and Yawei Li

Catalysts 2025, 15(10), 936; https://doi.org/10.3390/catal15100936 - 1 Oct 2025

Viewed by 2733

Abstract

This paper provides a systematic review of the latest advancements in metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for electrocatalytic carbon dioxide reduction. Both materials exhibit high specific surface areas, tunable pore structures, and abundant active sites. MOFs enhance CO₂ conversion [...] Read more.

This paper provides a systematic review of the latest advancements in metal-organic frameworks (MOFs) and covalent organic frameworks (COFs) for electrocatalytic carbon dioxide reduction. Both materials exhibit high specific surface areas, tunable pore structures, and abundant active sites. MOFs enhance CO₂ conversion efficiency through improved conductivity, optimized stability, and selective regulation—including bimetallic synergy, pulse potential strategies, and tandem catalysis. COFs achieve efficient catalysis through precise design of single or multi-metal active sites, optimization of framework conjugation, and photo/electro-synergistic systems. Both types of materials demonstrate excellent selectivity toward high-value-added products (CO, formic acid, C₂⁺ hydrocarbons), but they still face challenges such as insufficient stability, short operational lifespan, high scaling-up costs, and poor electrolyte compatibility. Future research should integrate in situ characterization with machine learning to deepen mechanistic understanding and advance practical applications. Full article

(This article belongs to the Special Issue Heterogeneous Catalysts for Electrochemical Hydrogen Storage)

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17 pages, 2176 KB

Open AccessFeature PaperEditor’s ChoiceArticle

A Study on Maximizing the Performance of a Concrete-Based TiO₂ Photocatalyst Using Hydrophilic Polymer Dispersion

by Jung Soo Kim, Kanghyeon Song, Jiwon Kim, Hyun-Ju Kang, Dayoung Yu, Hong Gun Kim and Young Soon Kim

Catalysts 2025, 15(10), 935; https://doi.org/10.3390/catal15100935 - 1 Oct 2025

Cited by 1 | Viewed by 948

Abstract

This study investigated the correlation between the dispersion stability and photocatalytic efficiency of titanium dioxide (TiO₂) nanoparticles for the development of self-cleaning functional concrete. After pretreatment of P25 TiO₂ with aqueous solutions of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and [...] Read more.

This study investigated the correlation between the dispersion stability and photocatalytic efficiency of titanium dioxide (TiO₂) nanoparticles for the development of self-cleaning functional concrete. After pretreatment of P25 TiO₂ with aqueous solutions of polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polyethylene glycol methyl ether (PEGME), dynamic light scattering (DLS) and zeta potential measurements were performed, and as a result, a 0.1 wt% PVA solution was optimal for inhibiting aggregation, with an average hydrodynamic diameter of 1.4 µm and a zeta potential of −11 mV. In methylene blue photolysis, the reaction rate constant (k_app) was 1.71 × 10⁻² min⁻¹ (R² = 0.98), which was improved by 11.4 times compared to the control group, and was about twice as high in the concrete specimen experiment. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses confirmed an anatase-to-rutile ratio of 81:19 particle sizes of 10–30 nm, and a specific surface area of 58.985 m²·g⁻¹. As a result, it is suggested that PVA pretreatment is a practical method to effectively improve the photocatalytic performance of TiO₂-based self-cleaning concrete. Full article

(This article belongs to the Special Issue Catalysis Accelerating Energy and Environmental Sustainability)

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12 pages, 1655 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Two-Dimensional Multilayered Ferroelectric with Polarization-Boosted Photocatalytic Hydrogen Evolution

by Yu Peng, Liangyao Li, Yilin Xu, Xing Wang and Yu Hou

Catalysts 2025, 15(9), 910; https://doi.org/10.3390/catal15090910 - 18 Sep 2025

Viewed by 1061

Abstract

Ferroelectric materials have attracted great attention for photocatalytic hydrogen (H₂) evolution due to their internal depolarization fields that promote carrier separation and directional migration. However, conventional inorganic ferroelectrics often suffer from wide band gaps and low conductivity, limiting their solar-to-hydrogen conversion [...] Read more.

Ferroelectric materials have attracted great attention for photocatalytic hydrogen (H₂) evolution due to their internal depolarization fields that promote carrier separation and directional migration. However, conventional inorganic ferroelectrics often suffer from wide band gaps and low conductivity, limiting their solar-to-hydrogen conversion efficiency. Here, we report a two-dimensional (2D) multilayered perovskite ferroelectric, [butylammonium]₂[ethylammonium]₂Pb₃I₁₀ (BAPI), which integrates robust spontaneous polarization (P_s) and excellent semiconductor properties to enable efficient photocatalysis. Under simultaneous light and ultrasonic excitation, BAPI/Pt (1 wt%) achieves a H₂ evolution rate of 1256 μmol g⁻¹ h⁻¹, which is twice that under light alone, due to dynamic polarization modulation that mitigates ionic screening and enhances internal electric fields. Notably, this enhancement vanishes when BAPI transitions to a centrosymmetric, nonpolar phase at 323 K, confirming the critical role of P_s. These findings offer a new pathway toward high-performance ferroelectric photocatalysts for solar hydrogen production. Full article

(This article belongs to the Section Photocatalysis)

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20 pages, 3176 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Photocatalytic Mineralization of Emerging Organic Contaminants Using Real and Simulated Effluents in Batch and Membrane Photoreactors

by Cristina Lavorato, Angela Severino, Pietro Argurio, Raffaele Molinari, Beatrice Russo, Alberto Figoli and Teresa Poerio

Catalysts 2025, 15(9), 904; https://doi.org/10.3390/catal15090904 - 18 Sep 2025

Viewed by 1144

Abstract

Conventional wastewater treatment plants (WWTPs) have limited efficiency in removing emerging pollutants (EPs), meaning these pollutants persist and lead to widespread ecological contamination. In this study, real effluents from a WWTP were characterized using TOC and Py-GC/MS, which indicated the presence of various [...] Read more.

Conventional wastewater treatment plants (WWTPs) have limited efficiency in removing emerging pollutants (EPs), meaning these pollutants persist and lead to widespread ecological contamination. In this study, real effluents from a WWTP were characterized using TOC and Py-GC/MS, which indicated the presence of various organic compounds that could be indicative of micro-nanoplastics (MNPs) or plastics additives. To address this challenge, we propose the use of a photocatalytic membrane reactor (PMR) as an advanced treatment system capable of achieving high degradation efficiency under mild operating conditions. Preliminary experimental tests were conducted using various commercial photocatalysts (TiO₂, WO₃, Nb₂O₅), four UV lamps, and oxidants (air, O₂) using added Gemfibrozil (GEM) as a drug model compound. Real effluent samples collected from WWTP were tested with and without pretreatment to remove coarse particles prior to photocatalysis. Mineralization was achieved in both cases, but it occurred at a higher rate for the pretreated effluent. The mineralization of GEM and EPs in real effluent was achieved within five hours under UV irradiation using titanium dioxide (TiO₂) as a low-cost photocatalyst in a PMR. The results highlight the potential of photocatalytic systems, and particularly PMRs, as a promising technology for removing recalcitrant pollutants in real effluents offering a viable solution for improved environmental protection. Full article

(This article belongs to the Special Issue 15th Anniversary of Catalysts—Recent Advances in Photocatalysis)

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14 pages, 2887 KB

Open AccessEditor’s ChoiceArticle

Enhanced Oxygen Reduction Reaction Activity of Carbon-Supported Pt-Co Catalysts Prepared by Electroless Deposition and Galvanic Replacement

by Angeliki Banti, Ivalina Avramova, Sotiris Sotiropoulos and Jenia Georgieva

Catalysts 2025, 15(9), 895; https://doi.org/10.3390/catal15090895 - 17 Sep 2025

Viewed by 1444

Abstract

The development of effective catalysts for the oxygen reduction reaction (ORR) is crucial for improving the performance of fuel cells. Efficient carbon-supported Pt-Co nanocatalysts were successfully prepared by a generic two-step method: (i) electroless deposition of a Co-P coating on Vulcan XC72R carbon [...] Read more.

The development of effective catalysts for the oxygen reduction reaction (ORR) is crucial for improving the performance of fuel cells. Efficient carbon-supported Pt-Co nanocatalysts were successfully prepared by a generic two-step method: (i) electroless deposition of a Co-P coating on Vulcan XC72R carbon powder and (ii) subsequent spontaneous partial galvanic replacement of Co by Pt, upon immersion of the Co/C precursor in a chloroplatinate solution. The prepared Pt-Co particles (of a core-shell structure) are dispersed on a Vulcan XC-72 support, forming agglomerates made of nanoparticles smaller than 10 nm. The composition and surface morphology of the samples were characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS) as well as transmission electron microscopy (TEM). The crystal structures of the Co-P/C precursor and Pt-Co/C catalyst were investigated by X-ray diffraction (XRD). XPS analysis was performed to study the chemical state of the surface layers of the precursor and catalyst. The electrochemical behavior of the Pt-Co/C composites was evaluated by cyclic voltammetry (CV). Linear sweep voltammetry (LSV) experiments were used to assess the catalytic activity towards the ORR and compared with that of a commercial Pt/C catalyst. The Pt-Co/C catalysts exhibit mass-specific and surface-specific activities (of j_m = 133 mA mg⁻¹ and j_esa = 0.661 mA cm⁻², respectively) at a typical overpotential value of 380 mV (+0.85 V vs. RHE); these are superior to those of similar electrodes made of a commercial Pt/C catalyst (j_m = 50.6 mA mg⁻¹; j_esa = 0.165 mA cm⁻²). The beneficial effect of even small (<1% wt.%) quantities of Co in the catalyst on Pt ORR activity may be attributed to an optimum catalyst composition and particle size resulting from the proposed preparation method. Full article

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13 pages, 3298 KB

Open AccessEditor’s ChoiceArticle

Maximally Exploiting the Fe²⁺ at the Interface of Micro and Nano Bubbles in the Fenton-Coupled Micro and Nano Bubble System for Organic Pollutant Degradation

by Qiongqiong He, Zhaoyang Song, Shaomeng Huang, Ruize Gao, Chao Han and Zhenyong Miao

Catalysts 2025, 15(9), 888; https://doi.org/10.3390/catal15090888 - 16 Sep 2025

Viewed by 962

Abstract

Heterocyclic compounds in high-salinity wastewater are highly resistant to degradation, posing significant treatment challenges. A hybrid micro-nano bubble Fenton system (FT-MNBs) was developed to enhance Fe²⁺ activation via interfacial effects. The FT-MNBs achieved a significantly higher indole degradation rate (0.0380 min⁻¹ [...] Read more.

Heterocyclic compounds in high-salinity wastewater are highly resistant to degradation, posing significant treatment challenges. A hybrid micro-nano bubble Fenton system (FT-MNBs) was developed to enhance Fe²⁺ activation via interfacial effects. The FT-MNBs achieved a significantly higher indole degradation rate (0.0380 min⁻¹) compared with micro and nano bubbles (MNBs) alone (0.0046 min⁻¹) and conventional Fenton (0.01008 min⁻¹). In real coking wastewater with a total dissolved solid (TDS) content of 3.266 g/L, FT-MNBs achieved COD removal efficiencies of 93.42% (initial COD 200 mg/L) and 72.54% (initial COD 10,000 mg/L), demonstrating excellent adaptability and efficiency in treating refractory high-salt organic wastewater. Electron spin resonance confirmed •OH as the main reactive species. Molecular simulations revealed that the MNB interface enhances the adsorption energy of Fe and H₂O₂, alters the Fe 3d orbital to better overlap with the O–O 2p orbital, and increases electron density—thus promoting O–O bond cleavage and free radical generation. The FT-MNBs not only enhances reaction kinetics but also offer scalability and energy efficiency, showing great potential for advanced industrial wastewater treatment. Full article

(This article belongs to the Section Catalytic Reaction Engineering)

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20 pages, 3592 KB

Open AccessEditor’s ChoiceArticle

One-Pot Synthesis of Sustainable Aviation Fuel from Brown Grease Using Multifunctional Zeolite-Supported Catalysts

by Clara Mongelli, Great Umenweke, Tyler St Clair, Gilles Caboche, Olivier Heintz, Robert Pace and Eduardo Santillan-Jimenez

Catalysts 2025, 15(9), 873; https://doi.org/10.3390/catal15090873 - 12 Sep 2025

Viewed by 1101

Abstract

The most viable way to decarbonize aviation in the near term is through Sustainable Aviation Fuel (SAF), most of which is currently produced via the deoxygenation of fats, oils, and greases (FOG) followed by a separate isomerization step. Multifunctional zeolite-supported catalysts offer several [...] Read more.

The most viable way to decarbonize aviation in the near term is through Sustainable Aviation Fuel (SAF), most of which is currently produced via the deoxygenation of fats, oils, and greases (FOG) followed by a separate isomerization step. Multifunctional zeolite-supported catalysts offer several advantages over existing formulations, such as enabling the use of waste FOG streams, performing their deoxygenation via decarboxylation/decarbonylation (deCO_x), and effecting the synthesis of SAF in one-pot. Previous work has shown that while supported Ni-Cu catalysts can afford excellent results in the conversion of waste FOG to fuel-like hydrocarbons via deCO_x, zeolitic materials represent promising supports in formulations employed for the synthesis of SAF. In this contribution, catalysts involving different zeolitic supports and the same Ni-Cu active phase were prepared, characterized, and tested in the conversion of brown grease to SAF to identify the carrier affording the best results. A Ni-Cu/ZSM-5 catalyst displayed the highest conversion and yield of SAF-like hydrocarbons relative to formulations supported on ZSM-22, SAPO-11, or SAPO-34 (these catalysts being referred to herein as NCZSM-5, NCZSM-22, NCSAPO-11, and NCSAPO-34). Full article

(This article belongs to the Special Issue Research Advances in Zeolites and Zeolite-Based Catalysts)

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28 pages, 2387 KB

Open AccessFeature PaperEditor’s ChoiceArticle

Synthesis and Catalytic Activity of Cu-Co/CeO₂ Catalysts in the Hydrogenation of Furfural to Pentanediols

by Rocío Maderuelo-Solera, Juan Antonio Cecilia-Buenestado, Francisco Vila, Rafael Mariscal, Pedro Jesús Maireles-Torres and Ramón Moreno-Tost

Catalysts 2025, 15(9), 872; https://doi.org/10.3390/catal15090872 - 11 Sep 2025

Cited by 1 | Viewed by 1286

Abstract

This study presents a comprehensive characterization of monometallic (Co or Cu) and bimetallic (Co-Cu) catalysts supported on cerium oxide (CeO₂). XRD and TEM analyses revealed that crystallinity decreases after reduction and that metal dispersion is highly dependent on composition, with cobalt [...] Read more.

This study presents a comprehensive characterization of monometallic (Co or Cu) and bimetallic (Co-Cu) catalysts supported on cerium oxide (CeO₂). XRD and TEM analyses revealed that crystallinity decreases after reduction and that metal dispersion is highly dependent on composition, with cobalt exhibiting greater dispersion than copper. The results confirmed a strong interaction between the metals and CeO₂, which alters the ceria structure and facilitates the reduction of the metal oxides. H₂-TPR and XPS data indicated that monometallic and the bimetallic 15Cu15Co catalysts achieved nearly complete reduction, whereas other bimetallic catalysts did not. Furthermore, CO chemisorption and H₂-TPD demonstrated that the hydrogen activation capacity correlates with the degree of catalyst reduction. Notably, bimetallic catalysts did not show enhanced hydrogen activation compared to their monometallic counterparts. This suggests that the dispersion and metal–support interaction are more critical factors for catalytic activity in this system than the formation of metal alloys. Although the furfural conversion was complete, the selectivity depended greatly on the catalyst composition. The 30Co_R catalyst was most selective for 1,5-pentanediol (38.4%), the 30Cu_R catalyst for 1,2-pentanediol (22.1%), and the bimetallic catalysts for THFA. Reutilising the 30Co_R catalyst after five catalytic cycles resulted in a gradual reduction in the selectivity of 1,5-pentanediol. Full article

(This article belongs to the Special Issue Sustainable Catalysis in Fine Chemicals, Pharmaceuticals and Biomass Valorization)

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