Catalysts

20 pages, 3439 KiB

Open AccessArticle

Rational Synthesis of a Dual Z-Scheme CdS/Ag₂MoO₄/β-Bi₂O₃ Heterojunction for the Deep Photodegradation of Methylene Blue and Analysis of Its Mechanisms

by Weiyi Ma, Yelin Xing, Xiaofeng Sun, Qianfei Ma, Yufen Gu, Hui Zhou, Guorong Liu, Jinyuan Ma and Hua Yang

Catalysts 2025, 15(5), 438; https://doi.org/10.3390/catal15050438 - 29 Apr 2025

Abstract

In this work, a novel dual Z-scheme CdS/Ag₂MoO₄/β-Bi₂O₃ (CAB) composite heterojunction was synthesized, with the ultrafine CdS nanoparticles decorating two different-sized particles. In the beginning, the synergistic effect between BO and AMO makes the 10% Ag [...] Read more.

In this work, a novel dual Z-scheme CdS/Ag₂MoO₄/β-Bi₂O₃ (CAB) composite heterojunction was synthesized, with the ultrafine CdS nanoparticles decorating two different-sized particles. In the beginning, the synergistic effect between BO and AMO makes the 10% Ag₂MoO₄/β-Bi₂O₃ (10AB) photocatalyst exhibit an optimal degradation efficiency of 87.1% for methylene blue (MB) of 10 mg·L⁻¹ within 60 min; furthermore, its photocatalytic activity was enhanced by incorporating CdS nanoparticles on the surface of the AB heterojunction. The results showed that the 25% CdS/10% AMO/BO (25C10AB) composite achieved a maximum MB degradation efficiency of 99%. Optical and photoluminescence measurements showed that the dual Z-scheme CAB heterojunction has high crystallinity and efficient charge carrier migration and separation, which makes the samples more efficient for removing pollutants. Theoretical studies (DFT/FEM calculations) were performed to better understand the migration direction of e⁻ and h⁺ in the photocatalytic degradation mechanism. This work provides a feasible approach to obtaining an efficient heterojunction composite photodegradation catalyst. Full article

(This article belongs to the Section Photocatalysis)

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17 pages, 5373 KiB

Open AccessArticle

Rotating Photo-Disc Reactor (RPR) Used in the Photo-Degradation of Pyridine Using Zinc Oxide as a Catalyst Composited with Aluminum Nanoparticles and Irradiated with Natural Light

by Carlos Montalvo, Edith Lemus, Claudia A. Aguilar, Rosa M. Cerón, Julia G. Cerón, Juan C. Robles and Alejandro Ruiz

Catalysts 2025, 15(5), 437; https://doi.org/10.3390/catal15050437 - 29 Apr 2025

Abstract

Pyridine was degraded in a rotating photo-disc reactor (RPR) using zinc oxide (ZnO) doped with aluminum nanoparticles (ZnO-Al) as a catalyst and natural light lamps. The reactor disks made of clay had a surface area of 329.7209 m². The reactor was [...] Read more.

Pyridine was degraded in a rotating photo-disc reactor (RPR) using zinc oxide (ZnO) doped with aluminum nanoparticles (ZnO-Al) as a catalyst and natural light lamps. The reactor disks made of clay had a surface area of 329.7209 m². The reactor was operated as a semi-batch system, where it handled a volume of 14.8 L and had a hydraulic residence time (HRT) of 72 h at 54 rpm with a constant flow rate. The results indicate an average degradation of 50.6% after an HRT of 72 h, with a maximum degradation of 62%. The characterization results confirm the effectiveness of the doping process, showing an aluminum concentration of 4.11% by mass in the catalyst, as determined by X-ray techniques. Overall, the doping process proved effective for the zinc oxide catalyst, as evidenced by a reduction in the catalyst bandgap from 3.25 eV for undoped ZnO to 3.08 eV for the doped version, making it sufficiently active under artificial visible light. Full article

(This article belongs to the Special Issue Environmental Catalysis in Advanced Oxidation Processes, 2nd Edition)

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16 pages, 2704 KiB

Open AccessFeature PaperArticle

Unveiling the Reaction Pathway of Oxidative Aldehyde Deformylation by a MOF-Based Cytochrome P450 Mimic

by Zehua Luo, Wentian Zhou, Junying Chen and Yingwei Li

Catalysts 2025, 15(5), 436; https://doi.org/10.3390/catal15050436 - 29 Apr 2025

Abstract

Understanding the reaction pathway of aldehyde deformylation catalyzed by natural enzymes has shown significance in developing synthetic methodologies and new catalysts in organic, biochemical, and medicinal chemistry. However, unlike other well-rationalized chemical processes catalyzed by cytochrome P450 (Cyt P450) superfamilies, the detailed mechanism [...] Read more.

Understanding the reaction pathway of aldehyde deformylation catalyzed by natural enzymes has shown significance in developing synthetic methodologies and new catalysts in organic, biochemical, and medicinal chemistry. However, unlike other well-rationalized chemical processes catalyzed by cytochrome P450 (Cyt P450) superfamilies, the detailed mechanism of the P450-catalyzed aldehyde deformylation is still controversial. Challenges lie in establishing synthetic models to decipher the reaction pathways, which normally are homogeneous systems for precisely mimicking the structure of the active sites in P450s. Herein, we report a heterogeneous Cyt P450 aromatase mimic based on a porphyrinic metal–organic framework (MOF) PCN-224. Through post-metalation of iron(II) triflate with the porphyrin unit, a five-coordinated Fe^II(Porp) compound could be afforded and isolated inside the resulting PCN-224(Fe) to mimic the heme active site in P450. This MOF-based P450 mimic could efficiently catalyze the oxidative deformylation of aldehydes to the corresponding ketones under room temperature using O₂ as the sole oxidant and triethylamine as the electron source, analogous to the NADPH reductase. The catalyst could be completely recovered after the catalytic reaction without undergoing structural decomposition or compromising its reactivity, representing it as one of the most valid mimics of P450 aromatase from both the structural and functional aspects. A mechanistic study reveals a strong correlation between the catalytic activity and the C^α-H bond dissociation energy of the aldehyde substrates, which, in conjunction with various trapping experiments, confirms an unconventional mechanism initiated by hydrogen atom abstraction. Full article

(This article belongs to the Special Issue Recent Advances in Metal-Organic Framework Catalysts)

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21 pages, 9608 KiB

Open AccessArticle

Impact of K on the Basicity and Selectivity of Pt/m-ZrO₂ Catalysts for Methanol Steam Reforming with co-fed H₂

by Braedon McFee, Michela Martinelli, Dali Qian, Phoenix Macfarlane, Fernanda Perez Marin and Gary Jacobs

Catalysts 2025, 15(5), 435; https://doi.org/10.3390/catal15050435 - 29 Apr 2025

Abstract

This study investigates the effect of potassium (K) promotion on Pt/m-ZrO₂ catalysts in methanol steam reforming (MSR), revealing critical insights into reaction pathways and catalyst performance. While increasing K loading reduces catalytic activity, it selectively enhances the hydrogen-producing formate dehydrogenation and de-carboxylation [...] Read more.

This study investigates the effect of potassium (K) promotion on Pt/m-ZrO₂ catalysts in methanol steam reforming (MSR), revealing critical insights into reaction pathways and catalyst performance. While increasing K loading reduces catalytic activity, it selectively enhances the hydrogen-producing formate dehydrogenation and de-carboxylation pathway. Structural analyses using HR-TEM and DRIFTS show that higher K concentrations block Pt sites and promote agglomeration, reshaping catalytic behavior. Notably, the 3.1% K-promoted catalyst achieves high stability at 358 °C, with a CO₂ selectivity exceeding 80% and minimal methane formation, outperforming the unpromoted catalyst in terms of CO and CH₄ selectivity. Temperature studies further demonstrate reduced CO selectivity at higher temperatures, highlighting distinct advantages of K-doped catalysts. These findings underscore the role of K in enhancing surface basicity and its impact on formate interaction, offering valuable insights for optimizing MSR catalysts and advancing hydrogen production technologies. Full article

(This article belongs to the Special Issue Catalytic Processes for Green Hydrogen Production)

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13 pages, 4001 KiB

Open AccessArticle

Growing Nanocrystalline Ru on Amorphous/Crystalline Heterostructure for Efficient and Durable Hydrogen Evolution Reaction

by Quanbin Huang, Xu Zhang, Li Tong, Yipu Liu and Shiwei Lin

Catalysts 2025, 15(5), 434; https://doi.org/10.3390/catal15050434 - 29 Apr 2025

Abstract

The design of efficient hydrogen evolution reaction (HER) catalysts to minimize reaction overpotentials plays a pivotal role in advancing water electrolysis and clean energy solutions. Ru-based catalysts, regarded as potential replacements for Pt-based catalysts, face stability challenges during catalytic process. The precise regulation [...] Read more.

The design of efficient hydrogen evolution reaction (HER) catalysts to minimize reaction overpotentials plays a pivotal role in advancing water electrolysis and clean energy solutions. Ru-based catalysts, regarded as potential replacements for Pt-based catalysts, face stability challenges during catalytic process. The precise regulation of metal–support interactions effectively prevents Ru nanoparticle degradation while optimizing interfacial electronic properties, enabling the simultaneous enhancement of catalytic activity and stability. Herein, we design an amorphous/crystalline support and employ in situ replacement to develop a Ru-NiP_x-Ni structure. The crystalline Ni phase with ordered atomic arrangement ensures efficient charge transport, while the amorphous phase with unsaturated dangling bonds provides abundant anchoring sites for Ru nanoclusters. This synergistic structure significantly enhances HER performance, which attains overpotentials of 19 mV at 10 mA cm⁻² and 70 mV at 100 mA cm⁻² in 1 m KOH, with sustained operation exceeding 55 h at 100 mA cm⁻². Electrochemical impedance spectroscopy analysis confirms that the Ru-NiP_x-Ni structure not only has a high density of active centers for HER, but also reduces the charge transfer resistance at the electrode–electrolyte interface, which effectively enhances HER kinetics. This study presents new directions for designing high-efficiency HER catalysts. Full article

(This article belongs to the Section Photocatalysis)

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20 pages, 14851 KiB

Open AccessArticle

Valorization of Residual Brewery Biomass for the Production of Counter Electrodes for Dye-Sensitized Solar Cells

by Camila Silva, A. M. R. Ramírez, Boris Pavez, María Eugenia Gonzalez, Matías Kopp, Pablo Meza and Mara Cea

Catalysts 2025, 15(5), 433; https://doi.org/10.3390/catal15050433 - 29 Apr 2025

Abstract

In this work, a biochar catalyst was developed from residual brewery spent grain (BSG) biomass and iron oxide to be applied in the counter electrode (CE) in dye-sensitized solar cells (DSSCs). The composite was obtained using a two-stage methodology based on microwave-assisted hydrothermal [...] Read more.

In this work, a biochar catalyst was developed from residual brewery spent grain (BSG) biomass and iron oxide to be applied in the counter electrode (CE) in dye-sensitized solar cells (DSSCs). The composite was obtained using a two-stage methodology based on microwave-assisted hydrothermal carbonization and pyrolysis, evaluating the influence of the pyrolysis temperature (700, 800 and 900 °C) on the properties and performance of the material. As result, composites with a high carbon and iron oxide content were obtained in a magnetite state attached to the surface. Furthermore, the physicochemical characteristics of the biochar showed similarities to those of reduced graphene oxide (rGO), which was attributed to the incorporation of iron oxide and the pyrolysis temperature. Electrochemical analysis showed that the composite pyrolyzed at 800 °C presented better catalytic activity and lower charge transfer resistance. Its application in the CE of a DSSC presented a current density of 10.44 mA/cm² and an efficiency of 3.05%, values close to the conventional Pt catalyst in DSSCs (Pt = 4.43%). This study validates the use of a composite based on residual brewery biomass with iron oxide in a CE, making it an alternative that contributes to the recovery of residues and the generation of sustainable technologies. Full article

(This article belongs to the Special Issue Catalytic Processes in Biofuel Production and Biomass Valorization, 3rd Edition)

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48 pages, 1309 KiB

Open AccessReview

An Overview of Solid Acid Catalysts in Lignocellulose Biorefineries

by Sujithra Balasubramanian, Ratheeshkumar Shanmugam, Arul Chan Basha, Malinee Sriariyanun, Saravanan Ramiah Shanmugam and Ponnusami Venkatachalam

Catalysts 2025, 15(5), 432; https://doi.org/10.3390/catal15050432 - 28 Apr 2025

Viewed by 22

Abstract

The continuous depletion of fossil fuels demands their replacement with renewable energy sources for the production of fuels, chemicals, and materials. Lignocellulosic biomass can serve as a sustainable raw material for the manufacturing of various industrial products, such as fine chemicals, biofuels, polysaccharides, [...] Read more.

The continuous depletion of fossil fuels demands their replacement with renewable energy sources for the production of fuels, chemicals, and materials. Lignocellulosic biomass can serve as a sustainable raw material for the manufacturing of various industrial products, such as fine chemicals, biofuels, polysaccharides, and biofuel precursors. Though numerous homogeneous catalysts are available for converting lignocellulosic biomass into fermentable sugars and biofuels, they require harsh environmental conditions, and their recovery is often difficult. Heterogeneous solid acid catalysts are efficient for biomass conversion, are environmentally benign, and can replace homogeneous catalysts in biorefineries to make them green. Zeolites, metal oxides, heteropoly acids, mesoporous silica nanoparticles, and carbon solid acid catalysts are some of the heterogeneous catalysts employed in lignocellulose biorefineries. This comprehensive review covers the different solid acids that can be used in biomass refineries, the factors influencing their catalytic activity, and the progress made towards their application in lignin depolymerization and the production of fermentable sugars, biofuels, and platform chemicals. Full article

(This article belongs to the Special Issue Catalytical Methods for the Production of Fine and Bulk Chemicals and Biomaterials from Biomass)

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15 pages, 4158 KiB

Open AccessArticle

The Effect of Surfactant P₁₂₃ on the KCuLaZrO₂ Catalysts in the Direct Conversion of Syngas to Higher Alcohols

by Jiaqian Yang, Jiayu Jin, Duomei Xue, Lifei Zhi, Zhongqiang Wang and Kai Sun

Catalysts 2025, 15(5), 431; https://doi.org/10.3390/catal15050431 - 28 Apr 2025

Viewed by 27

Abstract

The direct conversion of coal-based syngas to HA (higher alcohols) is of great significance, but it remains challenging stemming from the complexity of the reaction and the difficulty in regulating the alcohol distribution. P₁₂₃, as a structure-directing agent, is of great [...] Read more.

The direct conversion of coal-based syngas to HA (higher alcohols) is of great significance, but it remains challenging stemming from the complexity of the reaction and the difficulty in regulating the alcohol distribution. P₁₂₃, as a structure-directing agent, is of great significance for the preparation of mesoporous materials with specific pore sizes and pore structures. Therefore, a series of KCLZ-xP (KCuLaZrO₂-xP₁₂₃) catalysts with varying P₁₂₃ contents were prepared via the coprecipitation method and applied for HA synthesis. The KCLZ-30P catalyst exhibits a high CO conversion of 63.1%, a C₂₊OH/MeOH ratio of 0.98, and a comparable STY_ROH (space-time yield of total alcohol). Notably, it can selectively form linear alcohols in HAS while suppressing the formation of i-C₄ (branched alcohols). The results show that P₁₂₃ remarkably boosts catalytic activity through enlarging the specific surface area and facilitating the generation of t-ZrO₂. Simultaneously, P₁₂₃ suppresses the formation of i-C₄ alcohols by reducing the number of basic sites and weakening the strength of high-strength basic sites. Remarkably, the abundant CH_x and non-dissociated CO adsorbed on Cu⁰ facilitate the CO insertion process, thereby enhancing the C-C chain growth capability in linear alcohols, particularly favoring the formation of ethanol. These findings may offer the potential designing efficient catalysts for HAS (higher alcohol synthesis) from syngas. Full article

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21 pages, 15873 KiB

Open AccessArticle

Structured Mesh-Type Pt/Mn/γ-Al₂O₃/Al Catalyst Enhanced the CO Oxidation at Room Temperature by In Situ Generation of Hydroxyl: Behavior and Mechanism

by Meijia Cao, Qingli Shu, Ran Zhang and Qi Zhang

Catalysts 2025, 15(5), 430; https://doi.org/10.3390/catal15050430 - 28 Apr 2025

Viewed by 19

Abstract

Nowadays, Pt-based catalysts are widely applied in carbon monoxide (CO) removal at room temperature. However, the effects of abundant hydroxyl groups (OH*) on the decomposition of intermediate products and catalyst durability have rarely been studied. In this work, a novel hydroxyl-rich structured mesh-type [...] Read more.

Nowadays, Pt-based catalysts are widely applied in carbon monoxide (CO) removal at room temperature. However, the effects of abundant hydroxyl groups (OH*) on the decomposition of intermediate products and catalyst durability have rarely been studied. In this work, a novel hydroxyl-rich structured mesh-type Pt/Mn/γ-Al₂O₃/Al catalyst using a water vapor treatment (WVT) strategy to generate OH* in situ was developed. Firstly, density functional theory (DFT) calculations indicated that Mn-modification enhanced the adsorption capacity of CO and reduced the work function and the energy barrier of the catalytic reaction. Meanwhile, the water molecule dissociation ability of the Pt catalyst was improved. Secondly, the effects of WVT on the selected catalysts were investigated, and a possible reaction mechanism was proposed. XPS, FTIR, and TG results showed that WVT increased the content of OH*. Moreover, in situ FTIR further indicated that the increase of OH* content could alter the reaction path (from carbonate to formate pathway), thus enhancing the activity and durability of the catalyst. The selected catalyst exhibited excellent durability with 100% conversion within 200 h for 1000 ppm CO at room temperature. Full article

(This article belongs to the Section Catalytic Materials)

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15 pages, 2683 KiB

Open AccessFeature PaperArticle

Fe or Ni Catalytic Hydrothermal Depolymerization with Ethanol for Efficient Anaerobic Digestion of Corn Stover

by Xitong Wang, Hairong Yuan and Xiujin Li

Catalysts 2025, 15(5), 429; https://doi.org/10.3390/catal15050429 - 28 Apr 2025

Viewed by 61

Abstract

This study investigated the enhancement of anaerobic digestion (AD) performance of corn stover (CS) through Fe/Ni catalytic hydrothermal depolymerization with ethanol. The CS depolymerization process was conducted using Fe/C, Ni/C, Fe/CNT and Ni/CNT catalysts in combination with ethanol or water/ethanol solvents. The results [...] Read more.

This study investigated the enhancement of anaerobic digestion (AD) performance of corn stover (CS) through Fe/Ni catalytic hydrothermal depolymerization with ethanol. The CS depolymerization process was conducted using Fe/C, Ni/C, Fe/CNT and Ni/CNT catalysts in combination with ethanol or water/ethanol solvents. The results revealed that the depolymerization with catalyst-ethanol (DC-E) effectively disrupted the physical encapsulation of cellulose by lignin. It also showed that the Ni/CNT catalyst in ethanol significantly promoted β-O-4 bond cleavage in lignin, achieving a lignin conversion rate of 48.5% and 2.7 g/L total phenol concentration (TPC). The water/ethanol (9:1) system effectively degraded hemicellulose (53.6% conversion) while retaining over 90% cellulose for AD. Structural analysis revealed that DC disrupted cellulose hydrogen bonds, reducing crystallinity index (CrI decreased from 38.4% to 32.6%) and increasing cellulose accessibility to 909 mg/g (2.6 times higher than untreated CS). The efficient depolymerization of CS obviously improved the biodegradability of cellulose and hemicellulose, contributing to the increase of biomethane production. Biomethane yield (BY) of E-Ni/CNT was 18.1% and 27.6% higher than that of E-HP and the control group, respectively. These findings indicated that ethanol-promoted catalytic depolymerization of CS can enhance the performance of AD. Full article

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13 pages, 1383 KiB

Open AccessArticle

The Study of Regioselective Acylation of Geniposide by Using Whole-Cell Biocatalysts in Organic Solvents

by Rongling Yang, Ziling Huang, Xiangjie Zhao, Hongzhen Luo, Yuli Tong, Xiaoyan Li, Chun Zhu, Yu Wang and Yang Sun

Catalysts 2025, 15(5), 428; https://doi.org/10.3390/catal15050428 - 28 Apr 2025

Viewed by 81

Abstract

Geniposide, the predominant bioactive constituent identified in the traditional Chinese medicine herb Gardenia jasminoides, demonstrates clinically significant pharmacological properties. However, the clinical application of geniposide is significantly limited by its insufficient lipophilicity and consequent compromised oral bioavailability. To enhance the lipophilicity and [...] Read more.

Geniposide, the predominant bioactive constituent identified in the traditional Chinese medicine herb Gardenia jasminoides, demonstrates clinically significant pharmacological properties. However, the clinical application of geniposide is significantly limited by its insufficient lipophilicity and consequent compromised oral bioavailability. To enhance the lipophilicity and bioavailability of geniposide, a novel whole-cell-mediated catalytic approach was developed for the first time. Aspergillus oryzae whole cells exhibited the highest catalytic activity among microbial strains screened for geniposide decanoylation in the organic solvents. The optimal reaction conditions were identified as follows: acetonitrile served as the reaction solvent, with a substrate molar ratio of 15:1, a whole-cell dosage of 20 mg/mL, and the reaction temperature maintained at 50 °C. Under these optimized conditions, the initial reaction rate was 6.1 mmol/L·h, the conversion reached 99%, and the regioselectivity exceeded 99%. In addition, nine geniposide esters were successfully synthesized, exhibiting outstanding conversion efficiency and high regioselectivities. The pronounced regioselectivity exhibited by Aspergillus oryzae cells toward the 6′-hydroxy group of the glycoside ring in geniposide can be attributed to the lower steric hindrance at this position relative to other hydroxyl moieties, which may enter into the enzyme’s active site more easily to attack the acyl-enzyme intermediate. Full article

(This article belongs to the Special Issue Waste-to-Resources Through Catalysis in Green and Sustainable Way)

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32 pages, 966 KiB

Open AccessFeature PaperReview

Catalytic Aspects of Liquid Organic Hydrogen Carrier Technology

by Róbert Barthos, Ferenc Lónyi, Yuting Shi, Ágnes Szegedi, Anna Vikár, Hanna E. Solt and Gyula Novodárszki

Catalysts 2025, 15(5), 427; https://doi.org/10.3390/catal15050427 - 27 Apr 2025

Viewed by 89

Abstract

The surge in photovoltaic (PV) power generation has made it increasingly difficult to integrate the intermittent PV industry into the power grid while maintaining grid stability. The solution is to use the seasonal surplus of PV electricity to produce “green” hydrogen through water [...] Read more.

The surge in photovoltaic (PV) power generation has made it increasingly difficult to integrate the intermittent PV industry into the power grid while maintaining grid stability. The solution is to use the seasonal surplus of PV electricity to produce “green” hydrogen through water electrolysis and then use the hydrogen as an energy source or as a reactant in chemical processes in the chemical industry to produce value-added products. However, the development of advanced hydrogen storage technologies to ensure the safe handling, transportation, and distribution of H₂ is a major issue. The use of stable liquid organic hydrogen carriers (LOHCs) has emerged as a suitable technology for hydrogen storage. This review highlights prospective LOHC technologies based on reversible catalytic hydrogenation–dehydrogenation cycles of liquid organic molecules for hydrogen storage and release under mild temperature and pressure conditions. The state-of-the-art LOHC systems are critically reviewed, highlighting the most effective heterogeneous catalytic systems. Full article

(This article belongs to the Special Issue Sustainable Catalysis for Green Chemistry and Energy Transition)

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21 pages, 16026 KiB

Open AccessReview

Recent Advances in Catalytic Atroposelective Synthesis of Axially Chiral Quinazolinones

by Yilin Liu, Jiaoxue Wang, Yanli Yin and Zhiyong Jiang

Catalysts 2025, 15(5), 426; https://doi.org/10.3390/catal15050426 - 27 Apr 2025

Viewed by 147

Abstract

Quinazolinones, a class of nitrogen-containing heterocyclic compounds, occupy a crucial position in medicinal chemistry and materials science due to their significant application potential. In recent years, the catalytic asymmetric synthesis of axially chiral quinazolinones has emerged as a prominent research area, driven by [...] Read more.

Quinazolinones, a class of nitrogen-containing heterocyclic compounds, occupy a crucial position in medicinal chemistry and materials science due to their significant application potential. In recent years, the catalytic asymmetric synthesis of axially chiral quinazolinones has emerged as a prominent research area, driven by their prospective applications in the development of bioactive molecules, design of chiral ligands, and fabrication of functional materials. This review comprehensively summarizes recent advancements in the catalytic asymmetric synthesis of axially chiral quinazolinones, with a particular focus on the construction strategies for the three major structural types: the C–N axis, N–N axis, and C–C axis. Key synthetic methodologies, including atroposelective halogenation, kinetic resolution, condensation–oxidation, and photoredox deracemization, are discussed in detail. In addition, the review provides an in-depth analysis of the applications of various catalytic systems, such as peptide catalysis, enzymatic catalysis, metal catalysis, chiral phosphoric acid catalysis, and others. Despite the substantial progress made thus far, several challenges remain, including the expansion of the substrate scope, enhanced control over stereoselectivity, and further exploration of practical applications, such as drug discovery and asymmetric catalysis. These insights are expected to guide future research towards the development of novel synthetic strategies, the diversification of structural variants, and a comprehensive understanding of their biological activities and catalytic functions. Ultimately, this will foster the continued growth and evolution of this rapidly advancing field. Full article

(This article belongs to the Special Issue Recent Catalysts for Organic Synthesis)

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15 pages, 1971 KiB

Open AccessArticle

The Potential of Apricot Tree Resin as a Viable Feedstock for High-Value Chemicals via Hydrothermal Gasification

by Dilek Selvi Gökkaya

Catalysts 2025, 15(5), 425; https://doi.org/10.3390/catal15050425 - 27 Apr 2025

Viewed by 125

Abstract

This study investigates the hydrothermal gasification (HTG) of apricot tree resin, focusing on the yield and chemical composition of the resulting gas and aqueous phases. K₂CO₃ and KOH were used as catalysts within a temperature range of 300–600 °C, with [...] Read more.

This study investigates the hydrothermal gasification (HTG) of apricot tree resin, focusing on the yield and chemical composition of the resulting gas and aqueous phases. K₂CO₃ and KOH were used as catalysts within a temperature range of 300–600 °C, with a constant reaction time of 60 min. The results show that temperature and catalyst choice significantly influence gas yield, liquid composition, and solid residue formation. Higher temperatures increased the gas yield while decreasing aqueous and solid residues. The catalytic effect of K₂CO₃ and KOH enhanced the gaseous product conversion, with KOH achieving the highest gas yield and lowest residue formation at 600 °C. Among the liquid-phase compounds, carboxylic acids and 5-methyl furfural were the most abundant, reaching peak concentrations at 300 °C in the presence of K₂CO₃. The addition of alkali catalysts reduced key acidic intermediates such as glycolic, acetic, and formic acids. The inverse relationship between temperature and liquid/solid product formation underscores the importance of optimizing reaction conditions for efficient biomass conversion. These findings contribute to the growing field of biomass valorization by highlighting the potential of underutilized tree resins in sustainable biofuel production, advancing knowledge in renewable hydrogen production, and supporting the broader development of bio-based energy solutions. Full article

(This article belongs to the Special Issue Catalytic Gasification)

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23 pages, 5898 KiB

Open AccessReview

Carbon Dioxide Activation and Hydrogenation into Value-Added C1 Chemicals over Metal Hydride Catalysts

by Malesela A. Mafokoane, Xiaoxia Ou, Nicholas M. Musyoka and Fei Chang

Catalysts 2025, 15(5), 424; https://doi.org/10.3390/catal15050424 - 26 Apr 2025

Viewed by 186

Abstract

The utilisation of fossil fuels has resulted in the continuous increase in anthropogenic carbon dioxide (CO₂) emissions and has led to significant environmental impacts. To this end, the catalytic hydrogenation of captured CO₂ into value-added C1 chemicals has attracted great [...] Read more.

The utilisation of fossil fuels has resulted in the continuous increase in anthropogenic carbon dioxide (CO₂) emissions and has led to significant environmental impacts. To this end, the catalytic hydrogenation of captured CO₂ into value-added C1 chemicals has attracted great attention. In this case, significant research efforts have been directed towards the development of heterogeneous catalysts. Owing to the unique properties and functionalities of hydridic hydrogen (H⁻), metal hydrides have shown great promise in hydrogen-involved catalytic processes. This is attributed to their enhanced hydrogen (H₂) absorption-desorption reversibility and newly developed active sites. Nevertheless, their application in the activation and hydrogenation of CO₂ has been overlooked. In this review paper, we provide an overview of recent advances in catalytic CO₂ hydrogenation using metal hydride-based materials. Firstly, the reaction mechanisms of CO₂ hydrogenation toward different C1 products (CO, CH₄, CH₃OH and HCOOH) are introduced to better understand their application trend. Thereafter, we highlight the challenges of developing robust hydride catalysts with different components and structures that enable tuning of their catalytic activity and selectivity. A brief introduction of the CO₂ hydrogenation over typical homogeneous metal hydrides complexes is also presented. Lastly, conclusion, future outlook and perspectives are discussed. Full article

(This article belongs to the Special Issue Feature Review Papers in Catalysis for Sustainable Energy)

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15 pages, 2774 KiB

Open AccessArticle

Production of Hydroxylated Steroid Intermediates at 10-g Scale via the Original Sterol Modification Pathway in Mycolicibacterium neoaurum

by Lei Zou, Xue Li, Xue Sun, Shangfeng Chang and Zunxue Chang

Catalysts 2025, 15(5), 423; https://doi.org/10.3390/catal15050423 - 25 Apr 2025

Viewed by 192

Abstract

The aerobic catabolism of steroids in bacteria is highly conserved, and the mechanism of steroid degradation in mycobacteria has been extensively studied. However, the branching modification pathways of steroids in mycobacteria remain a mystery, including the likely roles of cytochromes P450. In this [...] Read more.

The aerobic catabolism of steroids in bacteria is highly conserved, and the mechanism of steroid degradation in mycobacteria has been extensively studied. However, the branching modification pathways of steroids in mycobacteria remain a mystery, including the likely roles of cytochromes P450. In this study, we unraveled the CYP105S17 converting androst-4-ene-3,17-dione (AD) to 17β-hydroxy-4-androstene-3,16-dione (16-oxo-TS), which was subsequently reduced to 16α,17β-dihydroxy-androst-4-ene-3-one (16α-OH-TS) under reductive conditions in Mycolicibacterium neoaurum. By applying this modification pathway, the genetically modified strains overexpressing CYP105S17 were able to produce 16α-OH-TS at titers 13.0 g/L with a conversion rate of 91.9% (supplemented with 20 g/L phytosterols as the substrate) through a two-stage biotransformation process. This is the first instance of utilizing the native P450 of Mycobacterium to produce 16-hydroxylated steroid intermediates at the 10 g scale. This work provides invaluable perspectives and guidance to researchers seeking to understand the complexities of steroid metabolism in bacteria, and also highlights the great potential of Mycobacterium as a production platform for hydroxylated steroid intermediates or pharmaceuticals. Full article

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15 pages, 2964 KiB

Open AccessFeature PaperArticle

Enhanced Adsorption Ability of CoS-Doped CuS for Promoting Electrochemical Oxidation of HMF

by Peng Cao, Yunliang Liu, Ruihua Yang, Yaxi Li, Yuanyuan Cheng, Jingwen Yu, Xinyue Zhang, Peter Phiri, Xinya Yuan, Yi Yang, Naiyun Liu, Yixian Liu and Haitao Li

Catalysts 2025, 15(5), 422; https://doi.org/10.3390/catal15050422 - 24 Apr 2025

Viewed by 121

Abstract

In the face of the intensifying energy and environmental challenges, the exploration of clean and sustainable approaches to energy conversion and utilization holds paramount significance. 5-Hydroxymethylfurfural (HMF), as a biomass platform compound with great potential, has drawn extensive attention for its oxidation to [...] Read more.

In the face of the intensifying energy and environmental challenges, the exploration of clean and sustainable approaches to energy conversion and utilization holds paramount significance. 5-Hydroxymethylfurfural (HMF), as a biomass platform compound with great potential, has drawn extensive attention for its oxidation to prepare 2,5-Furandicarboxylic acid (FDCA). In this study, a CoS-doped CuS composite catalyst (CoS–CuS) was synthesized via a one-step microwave–hydrothermal method for the electrocatalytic oxidation of HMF. The catalyst was comprehensively analyzed by means of multiple characterization techniques and electrochemical testing methods. The results demonstrate that the doping of CoS optimizes the surface electronic structure of the catalyst, enhancing its adsorption capabilities for HMF and OH⁻. Compared with the CuS catalyst, CoS–CuS in the 5-hydroxymethylfurfural oxidation reaction (HMFOR) shows a lower onset potential decreasing from 1.32 V_RHE to 1.29 V_RHE. At a potential of 1.4 V_RHE, the current density of CoS–CuS attains a value 2.02-fold that of CuS. Significantly, CoS–CuS demonstrates a substantially higher Faraday efficiency in the generation of FDCA, reaching nearly 89.1%. This study provides a promising approach for the construction of other efficient copper-based electrocatalysts. Full article

(This article belongs to the Section Electrocatalysis)

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26 pages, 4475 KiB

Open AccessReview

Research Progress on CO₂ Capture and Catalytic Conversion of Metal-Organic Frameworks Materials

by Yang Lei, Yangzixuan Xiao, Xiaolin Chen, Wentao Zhang, Xue Yang, Hu Yang and De Fang

Catalysts 2025, 15(5), 421; https://doi.org/10.3390/catal15050421 - 24 Apr 2025

Viewed by 217

Abstract

The increase in CO₂ emissions has been identified as a core driving factor in the intensification of the greenhouse effect. In order to achieve the dual-carbon vision, research on CO₂ capture and its catalytic conversion is receiving growing attention. Due to [...] Read more.

The increase in CO₂ emissions has been identified as a core driving factor in the intensification of the greenhouse effect. In order to achieve the dual-carbon vision, research on CO₂ capture and its catalytic conversion is receiving growing attention. Due to the high chemical stability of CO₂ itself, traditional separation technologies find it difficult to capture it onto catalysts. Currently, using hydrocarbons as carriers for catalytic reactions is the most common and efficient method. In recent years, metal-organic frameworks (MOFs) have shown their irreplaceable importance in CO₂ capture and catalytic conversion due to their unique adjustable and controllable pore structures and multiple active sites. This study integrates various classification criteria of MOFs, proposes a cooperative mechanism between metal doping and functional groups, and also reveals the CO₂ capture and catalytic conversion processes. In addition, we have conducted an in-depth discussion on the future development of continuous-flow microreactor technology and provided performance and property relationship diagrams for multiple MOF series, offering valuable reference material for future research in related fields. Full article

(This article belongs to the Special Issue Recent Advances in Metal-Organic Framework Catalysts)

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12 pages, 3414 KiB

Open AccessArticle

Mechanistic and Kinetic Insights into Hydroxyl Radical-Mediated Tetracycline Transformation in Photocatalytic Oxidation Processes

by Juanjuan Liu, Tao Sui, Yongcai Zhang, He Bian, Yi Lu and Chaosheng Zhu

Catalysts 2025, 15(5), 420; https://doi.org/10.3390/catal15050420 - 24 Apr 2025

Viewed by 166

Abstract

Antibiotic pollution, particularly via tetracycline (TC), poses significant environmental risks due to its recalcitrance and potential to induce antibiotic resistance. This study employed density functional theory (DFT) and transition state theory (TST) to investigate TC degradation by hydroxyl radicals (·OH), focusing on hydrogen [...] Read more.

Antibiotic pollution, particularly via tetracycline (TC), poses significant environmental risks due to its recalcitrance and potential to induce antibiotic resistance. This study employed density functional theory (DFT) and transition state theory (TST) to investigate TC degradation by hydroxyl radicals (·OH), focusing on hydrogen atom transfer (HAT) and radical adduct formation (RAF) pathways. Geometry optimizations and vibrational analysis validated stationary points, while intrinsic reaction coordinate (IRC) calculations confirmed transition states. Key findings reveal that RAF pathways exhibit lower activation barriers (1.23–30.33 kJ/mol) and greater exothermicity (−164.42 kJ/mol) compared to HAT pathways (3.51–42.04 kJ/mol, −109.58 kJ/mol), making them kinetically and thermodynamically dominant. Frontier molecular orbital (FMO) analysis links HAT to TC’s HOMO (π-orbital character on aromatic rings) and RAF to its LUMO (electrophilic sites). Rate constants calculated at 298 K (TST with Wigner correction) confirm RAF’s kinetic superiority (up to 7.0 × 10¹¹ s⁻¹), surpassing HAT’s fastest pathway (6.2 × 10¹¹ s⁻¹). These insights advance the understanding of TC degradation mechanisms and help with the design of efficient photocatalytic oxidation processes for antibiotic removal. Full article

(This article belongs to the Special Issue Recent Advances in Photocatalysis Research in Asia)

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18 pages, 6704 KiB

Open AccessFeature PaperArticle

Amorphous MnO₂ Supported on CN@SiO₂ for Levofloxacin Degradation via a Non-Radical Pathway by PMS Activation

by Longfei Xia, Xilin Wang, Jiahui Li and Dongyan Xu

Catalysts 2025, 15(5), 419; https://doi.org/10.3390/catal15050419 - 24 Apr 2025

Viewed by 94

Abstract

Mn-based catalysts have been extensively studied in advanced oxidation processes based on peroxymonosulfate (PMS) oxidants, demonstrating their significant potential for treating antibiotic-contaminated wastewater. In this study, an amorphous MnO₂-based composite catalyst (MnO₂/CN@SiO₂) was prepared and used to [...] Read more.

Mn-based catalysts have been extensively studied in advanced oxidation processes based on peroxymonosulfate (PMS) oxidants, demonstrating their significant potential for treating antibiotic-contaminated wastewater. In this study, an amorphous MnO₂-based composite catalyst (MnO₂/CN@SiO₂) was prepared and used to activate PMS for degrading levofloxacin (LEV). The effects of reaction conditions, such as reaction temperature, catalyst dosage, PMS concentration, and solution pH, on LEV degradation were comprehensively investigated. The interference of water components, e.g.,

{NO}_{3}^{-}

,

{SO}_{4}^{2 -}

, Cl⁻,

{CO}_{3}^{2 -}

, and humic acid, on the degradation efficiency of LEV was analyzed, and the stability of the catalysts was explored by cycling experiments. Finally, radical quenching experiments and electron paramagnetic resonance spectroscopy were employed to elucidate the contribution of active species to the degradation reaction process. A non-radical-based pathway for LEV degradation was proposed based on these results. Full article

(This article belongs to the Special Issue Environmentally Friendly Catalysts for Energy and Water Treatment Applications)

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14 pages, 2119 KiB

Open AccessArticle

Hydrodynamic Cavitation-Assisted Photo-Fenton Pretreatment and Yeast Co-Culture as Strategies to Produce Ethanol and Xylitol from Sugarcane Bagasse

by Carina Aline Prado, Ana Júlia E. B. da Silva, Paulo A. F. H. P. Fernandes, Vinicius P. Shibukawa, Fanny M. Jofre, Bruna G. Rodrigues, Silvio Silvério da Silva, Solange I. Mussatto and Júlio César Santos

Catalysts 2025, 15(5), 418; https://doi.org/10.3390/catal15050418 - 24 Apr 2025

Viewed by 145

Abstract

This study explored innovative approaches to produce ethanol and xylitol from sugarcane bagasse using a hydrodynamic cavitation-assisted photo-Fenton process as the pretreatment, and yeast co-culture for hydrolysate fermentation. Pretreatment conditions were optimized (20 mg/L of iron sulfate, pH 5.0, and reaction time of [...] Read more.

This study explored innovative approaches to produce ethanol and xylitol from sugarcane bagasse using a hydrodynamic cavitation-assisted photo-Fenton process as the pretreatment, and yeast co-culture for hydrolysate fermentation. Pretreatment conditions were optimized (20 mg/L of iron sulfate, pH 5.0, and reaction time of 14 min) resulting in glucan and xylan hydrolysis yields of 96% and 89%, respectively. The hydrolysate produced under these conditions was fermented using a co-culture of Saccharomyces cerevisiae IR2 (an ethanol-producing strain) and Candida tropicalis UFMGBX12 (a xylitol-producing strain). Optimal co-culture conditions consisted of using an inoculum concentration of 1.5 g/L for each yeast strain. After 36 h of fermentation, ethanol and xylitol concentrations reached 20 g/L and 13 g/L, respectively. These results demonstrate the potential of combining hydrodynamic cavitation-assisted photo-Fenton pretreatment with co-culture fermentation to simultaneously produce ethanol and xylitol. This strategy presents a promising approach for enhancing the efficiency of lignocellulosic biorefineries. Full article

(This article belongs to the Special Issue Topical Advisory Panel Members' Collection Series: Biomass Catalytic Conversion)

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3 pages, 126 KiB

Open AccessEditorial

Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry

by Victorio Cadierno and Raffaella Mancuso

Catalysts 2025, 15(5), 417; https://doi.org/10.3390/catal15050417 - 23 Apr 2025

Viewed by 97

Abstract

In advanced organic chemistry and polymer chemistry, catalysts are recognized as fundamental to making reactions selective, efficient, and achievable in a single step [...] Full article

(This article belongs to the Special Issue Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry)

23 pages, 8291 KiB

Open AccessArticle

Cu₁Ni₂/Al₂O₃ Catalyst from Its Hydrotalcite Precusor with Highly Active Sites for Efficient Hydrogenation of Levulinic Acid Toward 2-Methyltetrahydrofuran

by Jie Qin, Guohong Chen, Kaiqi Zheng, Jiajun Wu, Fanan Wang, Xueping Liu and Rengui Weng

Catalysts 2025, 15(5), 416; https://doi.org/10.3390/catal15050416 - 23 Apr 2025

Viewed by 107

Abstract

2-Methyltetrahydrofuran (2-MTHF), a hydrogenated derivative of levulinic acid (LA), is a biomass-derived platform compound with diverse and significant applications as a biofuel, gasoline additive, green solvent, and pharmaceutical synthesis intermediate. This study investigates the preparation of a Cu₁Ni₂/Al₂ [...] Read more.

2-Methyltetrahydrofuran (2-MTHF), a hydrogenated derivative of levulinic acid (LA), is a biomass-derived platform compound with diverse and significant applications as a biofuel, gasoline additive, green solvent, and pharmaceutical synthesis intermediate. This study investigates the preparation of a Cu₁Ni₂/Al₂O₃ catalyst through the calcination–reduction of CuNiAl hydrotalcite as a precursor, which was subsequently utilized in the hydrogenation of LA to produce 2-MTHF. The calcination–reduction process applied to CuNiAl hydrotalcite results in a lattice confinement effect. This method not only disperses the active metal sites but also alters the bonding patterns of the active metals, thereby enhancing the activity and stability of the Cu₁Ni₂/Al₂O₃ catalyst. The results indicate that complete conversion of LA and a 2-MTHF yield of 87.6% can be achieved under optimal conditions of 190 °C, 5 MPa hydrogen, and a reaction time of 5 h, demonstrating an efficient one-step conversion process. Additionally, the catalyst’s recyclability was assessed through multiple reuse tests, with a loss of activity of only 9.2% after six cycle experiments, suggesting its feasibility and reliability for industrial applications. Full article

(This article belongs to the Section Catalytic Materials)

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21 pages, 3335 KiB

Open AccessReview

Progress in Catalytic Oxidation of Noble Metal-Based Carbon Monoxide: Oxidation Mechanism, Sulfur Resistance, and Modification

by Yali Tong, Shuo Wang and Tao Yue

Catalysts 2025, 15(5), 415; https://doi.org/10.3390/catal15050415 - 23 Apr 2025

Viewed by 142

Abstract

Carbon monoxide (CO) is an important air pollutant generated from the incomplete combustion of fossil fuels, particularly in industrial processes such as iron and steel smelting, power generation, and waste incineration, posing environmental challenges that demand effective removal strategies. Recent advances in noble [...] Read more.

Carbon monoxide (CO) is an important air pollutant generated from the incomplete combustion of fossil fuels, particularly in industrial processes such as iron and steel smelting, power generation, and waste incineration, posing environmental challenges that demand effective removal strategies. Recent advances in noble metal catalysts for catalytic oxidation of CO, particularly Pt-, Pd-, and Rh-based systems, have been extensively studied. However, there is still a lack of systematic review on noble metal-based catalytic oxidation of CO, especially regarding the effects of different active components of the catalysts and the mechanism of sulfur resistance. Based on extensive research and literature findings, this study comprehensively concluded the advances in noble metal-based catalytic oxidation of CO. The effects of preparation methods, supports, and physicochemical properties on the catalytic performance of CO were explored. In addition, the mechanism of the catalytic oxidation of CO were further summarized. Furthermore, given the prevalence of SO₂ in the flue gas, the mechanism of sulfur poisoning deactivation of catalysts and the anti-sulfur strategies were further reviewed. Exploration of new supporting materials, catalyst surface reconstruction, doping modification, and other catalyst design strategies demonstrate potential in improving sulfur resistance and catalytic efficiency. This study provides valuable insights into the design and optimization of noble metal-based catalysts for the catalytic oxidation of CO. Full article

(This article belongs to the Section Environmental Catalysis)

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23 pages, 4612 KiB

Open AccessFeature PaperReview

Advancements in Chemical Recycling Catalysts for Plastic Waste in South Korea

by Taemin Jang, Ik Shin, Jungwook Choi, Sohyeon Lee, Hyein Hwang, Minchang Kim and Byung Hyo Kim

Catalysts 2025, 15(5), 414; https://doi.org/10.3390/catal15050414 - 23 Apr 2025

Viewed by 246

Abstract

Plastics are widely used in various industries because of their light weight, low cost, and high durability. The mass production and consumption of plastics have led to a rapid increase in plastic waste problem, necessitating the development of effective recycling technologies. The chemical [...] Read more.

Plastics are widely used in various industries because of their light weight, low cost, and high durability. The mass production and consumption of plastics have led to a rapid increase in plastic waste problem, necessitating the development of effective recycling technologies. The chemical recycling of plastics has emerged as a promising strategy to address these challenges, enabling the conversion of plastic waste into high-purity monomers or oils, even from contaminated or mixed plastic feedstock. This review focuses on the development of catalysts for the chemical recycling of plastics in South Korea, which has one of the highest per capita plastic consumption rates and both academic and industrial efforts in this field. We examine catalytic depolymerization processes for recovering monomers from polymers, such as polyethylene terephthalate (PET) and polycarbonate (PC), as well as catalytic pyrolysis processes for polyolefins, including polyethylene (PE), polypropylene (PP), and polystyrene (PS). By summarizing recent academic research and industrial initiatives in South Korea, this review highlights the strategic role of the country in advancing chemical recycling. Moreover, this review proposes future research directions including the development of reusable catalysts, energy-efficient recycling process, and strategies for recycling mixed or contaminated plastic waste. Full article

(This article belongs to the Special Issue State of the Art of Catalytical Technology in Korea, 2nd Edition)

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20 pages, 6664 KiB

Open AccessArticle

Constructing Pt/Hierarchical HY Bifunctional Catalysts for Selective Hydroisomerization of Phenanthrene to Alkyl-Adamantanes

by Nan Jiang, Xiaopo Niu, Danni Liu, Kaige Zhang, Zhen Guo, Yue Qin, Wenli Zhao, Xiangwen Zhang and Qingfa Wang

Catalysts 2025, 15(5), 413; https://doi.org/10.3390/catal15050413 - 23 Apr 2025

Viewed by 105

Abstract

Designing bifunctional catalysts for efficient hydroisomerization of phenanthrene to alkyl-adamantane is a great challenge for producing high-density fuels. Herein, a bifunctional Pt catalyst was fabricated by developing hierarchical H-MSY-T zeolites with an NOA-co strategy. The influence of different mesopore template agents on the [...] Read more.

Designing bifunctional catalysts for efficient hydroisomerization of phenanthrene to alkyl-adamantane is a great challenge for producing high-density fuels. Herein, a bifunctional Pt catalyst was fabricated by developing hierarchical H-MSY-T zeolites with an NOA-co strategy. The influence of different mesopore template agents on the hierarchical structure of H-MSY-T zeolite was investigated. Effective regulation of pore structure and acid distribution of zeolites was achieved by adjusting the templating agents. The block copolymer P123 promoted the formation of mesoporous structures via self-assembly with a large mesopore centered at 8 nm. Large mesoporous structure and suitable distribution of Bronsted acid boosted the hydroisomerization of phenanthrene. The highest alkyl-adamantane yield of 45.9 wt% was achieved on the Pt/MSY-P1 catalyst and a reaction network of hydroisomerization was proposed. This work provides guidance to design highly selective bifunctional catalysts for the one-step hydroconversion of tricyclic aromatic hydrocarbons into high-density fuels. Full article

(This article belongs to the Special Issue Advanced Catalysis for Energy and Environmental Applications)

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17 pages, 5147 KiB

Open AccessArticle

Response Surface Optimization of Biodiesel Production via Esterification Reaction of Methanol and Oleic Acid Catalyzed by a Brönsted–Lewis Catalyst PW/UiO/CNTs-OH

by Xuyao Xing, Qiong Wu, Li Zhang and Qing Shu

Catalysts 2025, 15(5), 412; https://doi.org/10.3390/catal15050412 - 23 Apr 2025

Viewed by 126

Abstract

In this study, a Brönsted–Lewis bifunctional acidic catalyst PW/UiO/CNTs-OH was synthesized via the hydrothermal method. The parameters for the esterification reaction of oleic acid with methanol catalyzed by PW/UiO/CNTs-OH were optimized using central composite design-response surface methodology (CCD-RSM). A biodiesel yield of 92.9% [...] Read more.

In this study, a Brönsted–Lewis bifunctional acidic catalyst PW/UiO/CNTs-OH was synthesized via the hydrothermal method. The parameters for the esterification reaction of oleic acid with methanol catalyzed by PW/UiO/CNTs-OH were optimized using central composite design-response surface methodology (CCD-RSM). A biodiesel yield of 92.9% was achieved under the optimized conditions, retaining 82.3% biodiesel yield after four catalytic cycles. The enhanced catalytic performance of PW/UiO/CNTs-OH can be attributed as follows: the [Zr₆O₄(OH)₄]¹²⁺ anchored on the surface of multi-walled carbon nanotubes (MWCNTs) can serve as nucleation sites for UiO-66, not only encapsulating H₃[P(W₃O₁₀)₄] (HPW) but also reversing the quadrupole moment of MWCNTs to generate Lewis acid sites. In addition, introduction of HPW during synthesis of UiO-66 decreases the solution pH, inducing the protonation of p-phthalic acid (PTA) to disrupt the coordination with the [Zr₆O₄(OH)₄] cluster, thereby creating an unsaturated Zr⁴⁺ site with electron pair-accepting capability, which generates Lewis acid sites. EIS analysis revealed that PW/UiO/CNTs-OH has higher electron migration efficiency than UiO-66 and PW/UiO. Furthermore, NH₃-TPD and Py-IR analyses showed that PW/UiO/CNTs-OH possessed high densities of Lewis acidic sites of 83.69 μmol/g and Brönsted acidic sites of 9.98 μmol/g. Full article

(This article belongs to the Section Biomass Catalysis)

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18 pages, 2996 KiB

Open AccessArticle

Bacterial Inactivation and Organic Pollutant Degradation in Slaughterhouse Wastewater Using Ag₂O/Ba/TiO₂ Nanocomposite

by Habib Ullah, Izhar Elahi, Sahar Saleem, Rab Nawaz, Shafi Ullah, Samia Qadeer, Bilal Kabeer, Muzammil Anjum, Yi Liu, Asfandyar Shahab, Abubakr M. Idris and Zepeng Rao

Catalysts 2025, 15(5), 411; https://doi.org/10.3390/catal15050411 - 23 Apr 2025

Viewed by 181

Abstract

Slaughterhouses generate a huge amount of highly polluted wastewater; if left untreated, this effluent could seriously threaten the environment and human health. In the present study, Ag₂O/Ba/TiO₂ nanocomposite was synthesized using the precipitation method, and its efficacy was investigated for [...] Read more.

Slaughterhouses generate a huge amount of highly polluted wastewater; if left untreated, this effluent could seriously threaten the environment and human health. In the present study, Ag₂O/Ba/TiO₂ nanocomposite was synthesized using the precipitation method, and its efficacy was investigated for the remediation of real slaughterhouse wastewater (SWW) under visible light. Its performance was assessed for the inactivation of bacterial strains identified in SWW and for the degradation of total organic solids, volatile solids, fixed solids, and heavy metals. The results indicated an excellent photocatalytic performance of the synthesized Ag₂O/Ba/TiO₂ nanocomposites, confirmed by 87.3% volatile solids, 30% total organic solids, and 40% fixed solids removal from SWW. The zone of inhibition runs from 4 to 9 mm, and the nanocomposites have demonstrated outstanding bacterial inactivation activity in this range. It has been shown that the synthetic Ag₂O/Ba/TiO₂ nanocomposites can function as an effective photocatalyst for the remediation of SWW and other waste products produced by various industries worldwide. Full article

(This article belongs to the Special Issue Advances in Enhancement of Catalytic Performance for Wastewater Treatment)

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17 pages, 3550 KiB

Open AccessArticle

Advanced Degradation of Aniline in Secondary Effluent from a Chemical Industry Park by Cobalt Ferrite/Peracetic Acid System

by Jinxiang Gao, Peishan Yang, Mingxin Zhu, Hua Zhou and Shunlong Pan

Catalysts 2025, 15(5), 410; https://doi.org/10.3390/catal15050410 - 23 Apr 2025

Viewed by 141

Abstract

The residual emerging pollutants in secondary effluent from a chemical industry park contain potential risks for natural waters. Herein, the cobalt ferrite/peracetic acid system was employed to destroy aniline, a typical emerging pollutant, with a reaction rate of 0.0147 min⁻¹ at pH [...] Read more.

The residual emerging pollutants in secondary effluent from a chemical industry park contain potential risks for natural waters. Herein, the cobalt ferrite/peracetic acid system was employed to destroy aniline, a typical emerging pollutant, with a reaction rate of 0.0147 min⁻¹ at pH 7.0. Singlet oxygen (¹O₂) served as the predominant reactive species for aniline degradation, with superoxide radicals (O₂⁻) and organic radicals (R-O) acting in secondary roles. The valence transition between Co(II) and Co(III) on the CoFe₂O₄ surface played a determining role in the reaction progression. The presence of anions and humic acids with low concentrations had minimal impact on aniline removal. Additionally, the CoFe₂O₄ catalyst demonstrated excellent recyclability, maintaining a pollutant removal rate above 93% over five consecutive cycles. Lastly, the CoFe₂O₄/PAA system demonstrates effective treatment of typical pollutants, including phenolic compounds, pesticides, antibiotics, and dyes, achieving removal rates of 77.48% to 99.99%. Furthermore, it significantly enhances water quality in the treatment of actual secondary effluent, offering a novel theoretical foundation and practical insights for applying this catalytic system in wastewater treatment. Full article

(This article belongs to the Topic Wastewater Treatment by Physical, Chemical, Photochemical, and Biological Processes, and Their Combinations)

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22 pages, 4566 KiB

Open AccessArticle

Evaluation of Vanadium Oxide Nanocatalysts over Graphene for Propylene Production Through Oxidative Propane Dehydrogenations

by Robabeh Mousavi, Armin Fazlinezhad, Abdollah Fallah Shojaei, Alimorad Rashidi and Moslem Fattahi

Catalysts 2025, 15(5), 409; https://doi.org/10.3390/catal15050409 - 23 Apr 2025

Viewed by 249

Abstract

This study reports an efficient and low-cost hydrothermal method for synthesizing vanadium oxide/graphene nanocatalysts. Field-emission scanning electron microscopy (FESEM) revealed the formation of nanostructured catalysts with consistent and directional shapes, as confirmed by X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectroscopy indicated the [...] Read more.

This study reports an efficient and low-cost hydrothermal method for synthesizing vanadium oxide/graphene nanocatalysts. Field-emission scanning electron microscopy (FESEM) revealed the formation of nanostructured catalysts with consistent and directional shapes, as confirmed by X-ray diffraction (XRD). Fourier transform infrared (FTIR) spectroscopy indicated the presence of V₂O₅ and graphene, highlighting their bonds and structures. Thermogravimetric analysis (TGA) identified three stages of weight loss in the nanocatalysts, corresponding to water molecule evaporation, decomposition of residual organics, and the formation of yellow vanadium pentoxide particles due to the oxidation of vanadium V⁴⁺. Gas chromatography analysis from 450 °C to 600 °C showed that ethylene selectivity increased with temperature, while propylene selectivity showed the opposite trend. The effectiveness of these nanocatalysts was assessed in the oxidative dehydrogenation of propane using temperature programmed reduction. The approach of graphene-based vanadium oxide nanostructures will open up a new insight into the fabrication of high-performance catalysts. Full article

(This article belongs to the Section Catalytic Reaction Engineering)

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