Catalysts

27 pages, 11423 KB

Open AccessReview

From Waste Mineralogy to Catalytic Reactivity: Decoding Mineral-Derived Platforms for Persulfate-Based Advanced Water Treatment

by Zeming Shi, Rilin Tan, Yusen Wu, Jun Zhang and Lixin Li

Catalysts 2026, 16(9), 851; https://doi.org/10.3390/catal16090851 - 21 Sep 2026

Viewed by 176

Abstract

The valorization of mineral wastes into functional catalysts provides a promising route for integrating solid waste management with advanced water purification. However, the catalytic potential of waste-derived materials is still commonly interpreted from elemental composition or preparation-induced performance enhancement, leaving the fundamental link [...] Read more.

The valorization of mineral wastes into functional catalysts provides a promising route for integrating solid waste management with advanced water purification. However, the catalytic potential of waste-derived materials is still commonly interpreted from elemental composition or preparation-induced performance enhancement, leaving the fundamental link between waste mineralogy and catalytic reactivity largely unresolved. This review introduces the concept of a mineralogical catalytic fingerprint (MCF) to establish a mechanistic framework connecting mineral origin, structural reconstruction, active-site evolution, and PMS/PDS activation behavior. Unlike conventional composition-based interpretations, the MCF framework highlights the decisive roles of mineral phases, element occurrence modes, defect chemistry, coordination environments, electronic structures, and oxidant interaction characteristics in determining catalytic pathways. The transformation of mine tailings and coal-derived mineral wastes into PMS/PDS activation platforms is systematically discussed, focusing on mineral reconstruction induced by acid treatment, thermal conversion, alkali activation, and interface engineering. The relationships among reconstructed active centers, radical and non-radical oxidation pathways, pollutant transformation, and catalyst stability are critically evaluated. Furthermore, the challenges associated with realistic wastewater applications, including matrix interference, metal leaching, catalyst recovery, reactor design, and life-cycle sustainability, are examined. By shifting the paradigm from waste composition-driven catalyst development toward mineralogy-guided catalytic design, this review provides an interpretive framework for understanding and engineering sustainable mineral-based catalysts, while establishing a basis for future predictive screening in practical persulfate oxidation processes. Full article

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18 pages, 22344 KB

Open AccessArticle

Construction of Co_0.5Mn_0.5Fe₂O₄ Spinel and Immobilized PVDF-Membrane for Confined Catalytic Flow Removal of Refractory Organics

by Juexiu Li, Wenlong Zhou, Miaomiao Li, Weiqiang Wang, Yue Liu, Yukun Li, Zhichao Shang and Chunzhen Fan

Catalysts 2026, 16(9), 850; https://doi.org/10.3390/catal16090850 - 21 Sep 2026

Viewed by 193

Abstract

Peroxymonosulfate (PMS) based on heterogeneous catalytic reaction is a promising advanced oxidation process (AOP) for the removal of refractory contaminants. However, it remains challenging owing to the decreasing catalytic oxidation efficiency induced by powder catalyst loss and insufficient mass transfer. In this study, [...] Read more.

Peroxymonosulfate (PMS) based on heterogeneous catalytic reaction is a promising advanced oxidation process (AOP) for the removal of refractory contaminants. However, it remains challenging owing to the decreasing catalytic oxidation efficiency induced by powder catalyst loss and insufficient mass transfer. In this study, spinel ferrite Co_0.5Mn_0.5Fe₂O₄ was successfully prepared and further immobilized on commercial polyvinylidene fluoride (PVDF) membrane. Both of the powder and immobilized catalysts were used as PMS activators for the decolorization of Rhodamine B. Within a 30 min reaction time, Co_0.5Mn_0.5Fe₂O₄ powder catalyst achieved removal efficiency of 80% for tetracycline hydrochloride and 100% for RhB. The Co_0.5Mn_0.5Fe₂O₄–PVDF membrane with a pore diameter of 0.1 μm exhibited excellent catalytic performance, achieving 100% RhB decolorization after seven filtration cycles. Quenching experiments and electron paramagnetic resonance (EPR) analysis demonstrated that RhB decolorization degradation involved both radical and non-radical pathway. This study proposed a porous membrane-based catalytic strategy for AOPs. The results suggest that smaller membrane pore diameters may contribute to an enhanced oxidation performance, providing new insights into the design of catalytic membrane systems. Full article

(This article belongs to the Special Issue Fiber Catalysts for Efficient Energy and Environmental Catalysis)

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20 pages, 1815 KB

Open AccessFeature PaperArticle

Hydrothermal Aging of Pd/γ-Al₂O₃ Catalysts for Lean CO Oxidation

by María Consuelo Revilla Nebreda, Alexander Groß, Volker Klemm, David Rafaja and Sven Kureti

Catalysts 2026, 16(9), 849; https://doi.org/10.3390/catal16090849 - 21 Sep 2026

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Abstract

Hydrothermal aging significantly affects the performance of Pd-based oxidation catalysts employed in lean-burn exhaust gas aftertreatment systems. In this study, powder catalysts with a Pd load of 2 wt.% were hydrothermally exposed to 650, 750, 850 and 950 °C, followed by comprehensive physicochemical [...] Read more.

Hydrothermal aging significantly affects the performance of Pd-based oxidation catalysts employed in lean-burn exhaust gas aftertreatment systems. In this study, powder catalysts with a Pd load of 2 wt.% were hydrothermally exposed to 650, 750, 850 and 950 °C, followed by comprehensive physicochemical characterization and evaluation of lean CO oxidation activity under steady-state conditions in the presence of H₂O. The catalytic performance was correlated with the number of accessible Pd surface sites quantified by temperature-programmed desorption of H₂ and scanning transmission electron microscopy. A marked loss of accessible Pd surface sites was observed after hydrothermal aging above 750 °C, accompanied by a corresponding decline in CO oxidation efficiency. Steady-state kinetic analysis revealed a progressive increase in the apparent activation energy from 36 kJ mol⁻¹ for the fresh catalyst to 74, 82 and 135 kJ mol⁻¹ after aging at successively higher temperatures. X-ray diffraction and X-ray photoelectron spectroscopy indicated dynamic changes in the Pd oxidation state during CO conversion to CO₂. The increase in activation energy was attributed to the combined effects of an increasing fraction of metallic Pd, Pd particle growth and phase transformations of the alumina support with increasing aging temperature. These findings demonstrate the pronounced structure sensitivity of lean CO oxidation on Pd/Al₂O₃ catalysts and highlight the critical impact of hydrothermal aging at temperatures of 750 °C and above on the physicochemical properties driving catalytic activity. Full article

(This article belongs to the Section Environmental Catalysis)

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13 pages, 1469 KB

Open AccessArticle

Stereoselective Synthesis of β-4′-Hydroxymethyl-Deleted Nucleosides via CPA-Ph₃PS Cooperative-Catalyzed Iodocyclization

by Qi Wang, Yuqian Liu, Yueyue Chen, Jia Liu, Jiarui Li, Jianing Li, Yanyan Peng and Jiang Nan

Catalysts 2026, 16(9), 848; https://doi.org/10.3390/catal16090848 - 20 Sep 2026

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Abstract

β-4′-Hydroxymethyl-deleted nucleosides are a class of four-carbon-sugar isonucleosides that possess significant research value in medicinal chemistry and artificial genetic polymer science. Nevertheless, current synthetic methodologies are hampered by several drawbacks, including poor diastereoselectivity, considerable side-product formation, and lengthy synthetic sequences. Herein, we report [...] Read more.

β-4′-Hydroxymethyl-deleted nucleosides are a class of four-carbon-sugar isonucleosides that possess significant research value in medicinal chemistry and artificial genetic polymer science. Nevertheless, current synthetic methodologies are hampered by several drawbacks, including poor diastereoselectivity, considerable side-product formation, and lengthy synthetic sequences. Herein, we report a cooperative catalytic strategy combining chiral phosphoric acid (CPA) and the achiral sulfur-containing Lewis base triphenylphosphine sulfide (Ph₃PS) for the stereoselective synthesis of β-4′-hydroxymethyl-deleted nucleosides via asymmetric alkene iodocyclization. Acting as a Brønsted acid, CPA anchors the hydroxyl nucleophilic site of the substrate through hydrogen-bonding interactions, whereas Ph₃PS activates the iodine source. The two catalysts work in concert to modulate the spatial conformation of iodonium intermediates, enabling the hydroxyl nucleophile to attack the iodonium carbon from the α-face of the substrate and thus construct the β-N-glycosidic bond with high stereoselectivity. This iodocyclization reaction delivers a diastereomeric ratio up to 98:2 and an isolated yield of 95%, and it can be readily scaled up to gram-scale preparation. Featuring mild reaction conditions and efficient practicality, the present synthetic strategy provides a concise and efficient asymmetric route toward 4′-hydroxymethyl-deleted isonucleosides. Full article

(This article belongs to the Special Issue Advances in Catalysis Science and Technology for Sustainable Development)

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16 pages, 5134 KB

Open AccessArticle

Integrated Valorization of Sargassum spp. into Ni/Biochar Electrocatalysts for Alkaline Oxygen Reduction

by Andrea Rosas-Castillo, B. J. Ayala-González, Ivonne Alonso-Lemus, Víctor Rejón and B. Escobar

Catalysts 2026, 16(9), 847; https://doi.org/10.3390/catal16090847 - 20 Sep 2026

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Abstract

Developing sustainable and low-cost electrocatalysts is important to reduce platinum dependence in alkaline fuel cells and support green hydrogen technologies. In this work, nickel nanoparticles (NiNPs) were synthesized through a green route using aqueous extracts of Sargassum spp. as reducing and stabilizing agents. [...] Read more.

Developing sustainable and low-cost electrocatalysts is important to reduce platinum dependence in alkaline fuel cells and support green hydrogen technologies. In this work, nickel nanoparticles (NiNPs) were synthesized through a green route using aqueous extracts of Sargassum spp. as reducing and stabilizing agents. The residual biomass was subsequently converted into activated biochar (BC) by KOH activation and pyrolysis at 700 °C, yielding a porous carbon support with a BET surface area of 1935 m² g⁻¹. Ni/BC electrocatalysts with nominal nickel loadings of 3, 5, 10, and 20 wt% were prepared and denoted BC–Ni3, BC–Ni5, BC–Ni10, and BC–Ni20. Physicochemical characterization confirmed the formation of Ni-based nanoparticles, graphitic carbon domains, and surface oxygen/nitrogen functionalities. Electrochemical evaluation in 0.1 M KOH showed that ORR performance depended on Ni loading. Among the Ni-based catalysts, BC–Ni20 delivered the highest current density (1.64 mA cm⁻² at 0.2 V vs. RHE), the most positive half-wave potential (0.67 V vs. RHE), and good durability after 5000 accelerated degradation cycles, with limited losses in onset and half-wave potentials. Although 10% Pt/Vulcan exhibited higher overall activity, the results demonstrate that Sargassum-derived Ni/biochar materials are promising platinum-group-metal-free electrocatalysts, offering a feasible route for biomass valorization and sustainable energy conversion. Full article

(This article belongs to the Special Issue Advanced Heterogeneous Catalysts for Sustainable Chemical Transformations: From Biomass Valorization to Clean Energy)

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15 pages, 9419 KB

Open AccessArticle

Study on the Catalytic Performance of Soluble Activated Carbon (AC)-ONa-Regulated CoFe₂O₄/Fe₂O₃/Co₃O₄-AC Composite Materials in Alkaline Hydrogen Evolution Reaction

by Min Cai, Ruike Guo, Houdi Deng, Wenzhu Liu and Xianxiang Liu

Catalysts 2026, 16(9), 846; https://doi.org/10.3390/catal16090846 - 20 Sep 2026

Viewed by 246

Abstract

With growing attention on renewable resources, hydrogen production as a sustainable alternative to increasingly depleted non-renewable fossil fuels has attracted significant interest. To develop economical electrocatalysts for HER that can replace platinum, this study synthesized a ternary CoFe₂O₄/Fe₂ [...] Read more.

With growing attention on renewable resources, hydrogen production as a sustainable alternative to increasingly depleted non-renewable fossil fuels has attracted significant interest. To develop economical electrocatalysts for HER that can replace platinum, this study synthesized a ternary CoFe₂O₄/Fe₂O₃/Co₃O₄-AC (activated carbon) nanocomposite via a urea-assisted one-step hydrothermal method, using water-soluble AC-ONa as a crystal growth regulator. The morphology and structure of the catalyst were thoroughly characterized by SEM, TEM, XRD, and XPS. Electrocatalytic water splitting performance was subsequently evaluated in 1.0 M KOH electrolyte. Results show that the catalyst requires an overpotential of 271 mV at a current density of 10 mA·cm⁻², significantly outperforming single-phase Fe₂O₃-AC (576 mV), Co₃O₄-AC (511 mV), and CoFe₂O₄/Fe₂O₃/Co₃O₄ (291 mV). The Tafel slope is 72.2 mV·dec⁻¹, consistent with the Volmer–Heyrovsky pathway. After a 10 h i-t stability test, the HER current remained essentially unchanged; moreover, after 1000 cyclic voltammetry cycles, the overpotential slightly decreased to 259 mV, demonstrating excellent HER stability. This work establishes a facile one-pot strategy for constructing multicomponent metal-oxide composite materials, in which soluble carbon additives play a key role in guiding interfacial growth. This method is easily scalable and avoids complicated procedures, providing a potential route for designing low-cost, highly active non-noble metal catalysts for alkaline HER. Full article

(This article belongs to the Special Issue Graphene and Other Carbon-Based Supported Heterogeneous Catalysts)

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14 pages, 5209 KB

Open AccessArticle

Mesoporous Confinement of Ni Nanoparticles in Al₂O₃ Enables Highly Selective CO Production via Reverse Water–Gas Shift Reaction

by Shuying Liang, Xianhong Li, Jianzhong Guo and Chunzheng Wu

Catalysts 2026, 16(9), 845; https://doi.org/10.3390/catal16090845 - 19 Sep 2026

Viewed by 243

Abstract

Nickel-based catalysts have been extensively investigated for the reverse water–gas shift (RWGS) reaction; however, their practical application is often hindered by the undesired methanation side reaction. To address this challenge, we developed mesoporous Al₂O₃ as a support to disperse and [...] Read more.

Nickel-based catalysts have been extensively investigated for the reverse water–gas shift (RWGS) reaction; however, their practical application is often hindered by the undesired methanation side reaction. To address this challenge, we developed mesoporous Al₂O₃ as a support to disperse and spatially confine Ni nanoparticles. Ni/Al₂O₃ catalysts were synthesized via two strategies: pre-introduction of the Ni precursor during the sol–gel formation of mesoporous Al₂O₃ and post-impregnation of the Ni precursor onto preformed mesoporous Al₂O₃. Compared with Ni supported on conventional γ-Al₂O₃, both catalysts exhibited lower CO₂ hydrogenation activity but significantly improved CO selectivity. Through a combination of structural characterizations and kinetic analyses, we revealed that pre-introduced Ni species were transformed into smaller Ni nanoparticles confined within the mesoporous channels, accompanied by stronger metal-support interactions. These structural features did not alter the intrinsic RWGS reaction but effectively suppressed the competing methanation reaction, thereby achieving superior CO selectivity. This study demonstrates that rational regulation of support morphology and control over metal incorporation strategies provide an effective approach for steering CO₂ hydrogenation toward selective CO production. Full article

(This article belongs to the Special Issue Catalysts for CO₂ Conversions)

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25 pages, 4313 KB

Open AccessArticle

Efficient Daunorubicin Degradation and Detoxification via UV-LED/ZVI/Oxone: LC-MS-Based Transformation Pathways

by Syed Kashif Ali, Muhammad Imran Kanjal, Muhammad Irfan Ahamad, Yehia Hazzazi, Mari Sumayli, Faten A. M. Abdelaziz, Hussain J. Alathlawi and Lotfi Mouni

Catalysts 2026, 16(9), 844; https://doi.org/10.3390/catal16090844 - 19 Sep 2026

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Abstract

Pharmaceutical residues, particularly anticancer compounds, are persistent aquatic contaminants that require efficient treatment strategies. This study developed a UV-LED-assisted peroxymonosulfate (PMS)/zero-valent iron (ZVI) advanced oxidation system for the degradation and toxicity reduction of daunorubicin in aqueous solution. The effects of key operational parameters [...] Read more.

Pharmaceutical residues, particularly anticancer compounds, are persistent aquatic contaminants that require efficient treatment strategies. This study developed a UV-LED-assisted peroxymonosulfate (PMS)/zero-valent iron (ZVI) advanced oxidation system for the degradation and toxicity reduction of daunorubicin in aqueous solution. The effects of key operational parameters were optimized using response surface methodology. Under optimal conditions (pH 3, PMS 1.5 mM, ZVI 0.3 g/L, and daunorubicin 10 mg/L), nearly complete degradation was achieved within 15 min, following pseudo-first-order kinetics (R² > 0.95). LC–MS analysis revealed the formation of transformation products and suggested oxidative fragmentation pathways of daunorubicin. The process achieved 65% total organic carbon removal after 6 h, indicating substantial but incomplete mineralization. Fe²⁺ evolution and ESR analysis demonstrated that ZVI-mediated PMS activation generated reactive species, with sulfate radicals playing a major role and hydroxyl radicals contributing to oxidation. Toxicity and mutagenicity assays confirmed significant reductions in biological effects after treatment. These findings demonstrate that the UV-LED/PMS/ZVI system is a promising approach for the treatment of daunorubicin-containing wastewater. Full article

(This article belongs to the Special Issue Photocatalytic Water Splitting and Pollutant Degradation: Recent Progress and Emerging Trends)

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26 pages, 2503 KB

Open AccessReview

From Lignocellulosic Residues to Reusable Biochar Catalysts: Stability, Regeneration, and Closed-Loop Biorefinery Integration

by Stefano Bellucci

Catalysts 2026, 16(9), 843; https://doi.org/10.3390/catal16090843 - 19 Sep 2026

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Abstract

Residue-derived biochar catalysts can couple catalyst manufacture with biomass valorization, but renewable origin does not guarantee catalytic superiority, durability, or circularity. This critical review examines reusable biochar catalysts and catalyst supports from lignocellulosic residues across biodiesel synthesis, catalytic pyrolysis, tar reforming, hydrodeoxygenation, and [...] Read more.

Residue-derived biochar catalysts can couple catalyst manufacture with biomass valorization, but renewable origin does not guarantee catalytic superiority, durability, or circularity. This critical review examines reusable biochar catalysts and catalyst supports from lignocellulosic residues across biodiesel synthesis, catalytic pyrolysis, tar reforming, hydrodeoxygenation, and platform-chemical production. It focuses on the limits of feedstock–process correlations, the distinction between biochar as catalyst and as support, the strength of active-site evidence, and the effects of deactivation, regeneration, shaping, and material loss. A 23-case quantitative benchmark shows that catalyst loading and repeated-use performance are reported more often than recovered dry mass, cycle-resolved elemental balances, or continuous validation. Closed-loop metrics are defined for catalyst yield, cumulative productivity, regeneration efficiency, elemental retention, water and chemical intensity, and carbon efficiency. The strongest case for residue-derived catalysts is therefore an integrated material loop with measured durability and resource balances, not feedstock origin or surface area alone. Full article

(This article belongs to the Special Issue Catalysts from Lignocellulose to Biofuels and Bioproducts)

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52 pages, 16167 KB

Open AccessReview

Rational Design of Advanced Materials for Photothermal Catalytic CO₂ Reduction: Progress and Perspectives

by Chunling Xin, Jianan Lang, Wei Zhang, Dongxin Yu and Xishi Tai

Catalysts 2026, 16(9), 842; https://doi.org/10.3390/catal16090842 - 19 Sep 2026

Viewed by 251

Abstract

Driven by the global carbon neutrality goal, converting CO₂ into value-added chemicals and fuels is a critical pathway for energy storage and carbon recycling. However, traditional photocatalysis suffers from severe charge recombination and low efficiency, while thermocatalysis is restricted by enormous energy [...] Read more.

Driven by the global carbon neutrality goal, converting CO₂ into value-added chemicals and fuels is a critical pathway for energy storage and carbon recycling. However, traditional photocatalysis suffers from severe charge recombination and low efficiency, while thermocatalysis is restricted by enormous energy consumption. Photothermal catalysis has emerged as a promising strategy by seamlessly integrating solar-driven charge excitation and localized thermal activation to overcome the kinetic and thermodynamic limitations of CO₂ reduction. This review systematically summarizes the recent progress in the rational design of advanced materials for photothermal CO₂ reduction. We begin by outlining the fundamental photothermal conversion mechanisms and categorizing the synergistic effects into three modes: photo-driven thermocatalysis, thermo-assisted photocatalysis, and synergistic photothermal catalysis. A quantitative evaluation framework for mechanistic decoupling is then established, integrating temperature-matched dark controls, spectrally resolved measurements, ultrafast in situ characterizations, and micro-nanoscale thermometry. We subsequently review state-of-the-art material design strategies, highlighting plasmonic metals, defect-engineered semiconductors, carbon-based nanocomposites, and tailored heterostructures, with critical comparisons of their respective advantages and operating conditions. Furthermore, we provide deep insights into the regulation of product selectivity, explicitly distinguishing the reverse water-gas shift reaction (RWGS), CO₂ methanation, and photocatalytic reduction pathways, and analyzing the competitive pathways of C₁ products and the kinetic bottlenecks of C₂₊ generation. Advanced microstructural optimization strategies, such as single-atom doping and facet engineering tailored to modulate the binding energies of key intermediates, are systematically discussed. We then examine energy efficiency analysis and advanced reactor engineering, emphasizing that genuine sustainability requires system-wide energy audits rather than reliance on apparent reaction rates. Finally, we outline the current challenges and future perspectives regarding long-term stability, thermal management, reactor design, and industrial-scale fabrication. This review aims to provide a clear roadmap for developing highly efficient and selective photothermal catalysts, thereby accelerating their practical applications in the green carbon economy. Full article

(This article belongs to the Special Issue Catalysis for a Sustainable Future: Powering New Energy and Protecting the Environment)

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24 pages, 1323 KB

Open AccessReview

Recent Progress in LaNi_1-xFe_xO_3-δ Perovskite Oxides for SOFC Cathodes and Energy Catalysis: The Role of the Ni/Fe Ratio

by Zhirui Jiang, Youchen Lin, Xinyi Li, Zhihua Deng, Song Han, Yuqi Wang, Chengzhi Guan, Xianlong Du, Guoping Xiao, Jianqiang Wang, Siew Hwa Chan and Lan Zhang

Catalysts 2026, 16(9), 841; https://doi.org/10.3390/catal16090841 - 19 Sep 2026

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Abstract

LaNi_1-xFe_xO_3-δ (LNF) perovskite oxides are promising Sr- and Co-free materials for solid oxide fuel cell (SOFC) cathodes and energy-related catalytic applications. The Ni/Fe ratio strongly influences their electronic structure, defect chemistry, transport properties, reducibility, and structural stability. This [...] Read more.

LaNi_1-xFe_xO_3-δ (LNF) perovskite oxides are promising Sr- and Co-free materials for solid oxide fuel cell (SOFC) cathodes and energy-related catalytic applications. The Ni/Fe ratio strongly influences their electronic structure, defect chemistry, transport properties, reducibility, and structural stability. This review examines how these composition-dependent properties affect LNF synthesis and performance across different applications. For SOFC cathodes, LaNi_0.6Fe_0.4O₃ is an important reference composition because of its favorable balance of conductivity, thermal compatibility, and stability. In oxygen evolution electrocatalysis and other applications, however, the preferred Ni/Fe ratio varies substantially with the required reaction properties and operating conditions. Synthesis, microstructure, surface reconstruction, reduction, and exsolution further affect the functional state of LNF. Therefore, no universally optimal Ni/Fe ratio exists. Composition should instead be selected for the intended application, followed by appropriate synthesis and surface/interface engineering to further improve performance. Full article

(This article belongs to the Section Catalytic Materials)

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28 pages, 2288 KB

Open AccessArticle

Reactive Pathways, Inorganic-Ion Effects, and Water-Matrix Impacts in Peracetic Acid Activation by an Ordinary Steel-Copper Galvanic Cell for Organic Pollutant Removal

by Abdulmajeed Baker, Oualid Hamdaoui, Abdulrahman Al-Awadi, Lahssen El Blidi and Abdulaziz Alghyamah

Catalysts 2026, 16(9), 840; https://doi.org/10.3390/catal16090840 - 19 Sep 2026

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Abstract

Peracetic acid (PAA) activation by macroscopic galvanic materials offers a low-complexity alternative to soluble-metal dosing and engineered nanocatalysts. This study investigates reactive pathways and water-matrix effects during PAA activation by an ordinary steel-copper galvanic cell using Sunset Yellow FCF (SSY) as a model [...] Read more.

Peracetic acid (PAA) activation by macroscopic galvanic materials offers a low-complexity alternative to soluble-metal dosing and engineered nanocatalysts. This study investigates reactive pathways and water-matrix effects during PAA activation by an ordinary steel-copper galvanic cell using Sunset Yellow FCF (SSY) as a model contaminant. Under the reference conditions ([SSY]₀ = 5 mg/L, [PAA]₀ = 0.13 mM, natural initial pH ≈ 4.5, 400 rpm), approximately 95% SSY decolorization was observed within 5 min, and decolorization was near complete within 9 min. PAA alone produced no measurable decrease in SSY concentration during the same experimental period, confirming that direct decolorization by unactivated PAA was negligible under the investigated conditions. Cu/PAA alone produced no measurable decrease in SSY absorbance at 482 nm, demonstrating that copper alone did not appreciably activate PAA under the investigated conditions. When considered together with established Fe-Cu galvanic behavior, this result supports a predominantly cathodic role for copper in the coupled system; however, the extent of any copper-induced enhancement of steel dissolution was not quantified. Strong inhibition by TEMPO and ascorbic acid, combined with weaker responses to tert-butanol and nitrobenzene, was consistent with a major contribution from PAA-derived organic-radical chemistry and argued against freely diffusing HO^• as the dominant oxidant. Br⁻ markedly promoted SSY chromophore disappearance, whereas NO₂⁻, HCO₃⁻, and CO₃²⁻ strongly inhibited the process. Without deliberate pH adjustment, final decolorization was approximately 5.5%, 9%, and 43% in Zamzam water, tap water, and seawater, respectively. Adjustment to pH 3 increased decolorization to approximately 86% in Zamzam water and 61% in tap water, whereas seawater remained strongly inhibitory, with approximately 37–38% decolorization. These percentages quantify the loss of absorbance at 482 nm and do not establish complete molecular degradation or mineralization. The results demonstrate that galvanic PAA activation is governed jointly by Fe-mediated activation, reactive-species chemistry, pH/alkalinity, and non-additive water-matrix effects. Full article

(This article belongs to the Special Issue Innovations in Environmental Catalysis and Green Materials for Low Carbon Development)

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17 pages, 6231 KB

Open AccessArticle

Cl-Modified N-Type Cu₂O Thin Films for Enhanced Photocatalytic Degradation of Norfloxacin Under Visible-Light Irradiation

by Yuchen Wei, Qinggong Ji, Zongbin Liu, Jian Zhang, Lei Chen, Ningning Zhao and Xiaojiao Yu

Catalysts 2026, 16(9), 839; https://doi.org/10.3390/catal16090839 - 18 Sep 2026

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Abstract

Cl-modified n-type Cu₂O thin films were prepared on indium tin oxide substrates through potentiostatic electrodeposition and investigated for the photocatalytic removal of norfloxacin (NOR). Cyclic voltammetry and X-ray diffraction identified −0.65 V and pH 5.7 as suitable deposition conditions. Cl addition [...] Read more.

Cl-modified n-type Cu₂O thin films were prepared on indium tin oxide substrates through potentiostatic electrodeposition and investigated for the photocatalytic removal of norfloxacin (NOR). Cyclic voltammetry and X-ray diffraction identified −0.65 V and pH 5.7 as suitable deposition conditions. Cl addition regulated the nucleation and growth of Cu₂O, producing pronounced changes in crystal orientation, surface morphology, and electronic properties. The thin film obtained with 10 mmol L⁻¹ KCl (Cl₁₀-Cu₂O) exhibited the strongest (111) preferred orientation and a flower-like morphology. X-ray photoelectron spectroscopy confirmed the presence of Cl species and revealed predominantly Cu⁺, together with defect-associated oxygen environments and a small proportion of surface Cu²⁺. The Mott–Schottky analysis demonstrated a transition from p-type conductivity in pristine Cu₂O to n-type behavior after Cl incorporation. The optical band gap increased from 1.94 to 2.04 eV, indicating modification of the electronic structure. Among the investigated samples, Cl₁₀-Cu₂O delivered the highest photocurrent density (0.101 mA cm⁻²), the largest open-circuit photovoltage (11.981 mV), and the lowest interfacial charge-transfer resistance. Its apparent pseudo-first-order rate constant reached 0.00539 min⁻¹, approximately 1.61 times that of pristine Cu₂O. Scavenger experiments indicated that photogenerated holes were the predominant oxidative species, while ⋅O₂⁻ and ⋅OH also participated in NOR transformation. The improved photocatalytic activity was attributed to the combined effects of conductivity-type conversion, controlled defect formation, enhanced charge separation and transfer, favorable crystal orientation, and hierarchical surface morphology. Full article

(This article belongs to the Section Photocatalysis)

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4 pages, 160 KB

Open AccessEditorial

New Trends in Industrial Biocatalysis

by María Guadalupe Sánchez-Otero and Rosa María Oliart-Ros

Catalysts 2026, 16(9), 838; https://doi.org/10.3390/catal16090838 - 17 Sep 2026

Viewed by 307

Abstract

Industrial biocatalysis stands as a pivotal technological tool for achieving the Sustainable Development Goals set by the United Nations, since it enables the most efficient chemical transformations in many industrial activities [...] Full article

(This article belongs to the Special Issue New Trends in Industrial Biocatalysis)

14 pages, 2164 KB

Open AccessFeature PaperArticle

Facile Etching Process for the Porous Structure of Hexagonal Boron Nitride as a Catalyst Support Using Metal Oxides Under Low-Temperature Conditions

by Myeung-Jin Lee, Donghyeok Kim, Nahea Kim, Sang-Hyeok Seo, Dahye Park, Tae-hyung Kim, Bora Jeong and Hong-Dae Kim

Catalysts 2026, 16(9), 837; https://doi.org/10.3390/catal16090837 - 17 Sep 2026

Viewed by 182

Abstract

Many technological fields have adopted composites with active material–support configurations, where the active materials dictate the catalytic activity, and the supports improve the properties. Hexagonal boron nitride (h-BN) is a promising and highly stable support material with limited applications because it is difficult [...] Read more.

Many technological fields have adopted composites with active material–support configurations, where the active materials dictate the catalytic activity, and the supports improve the properties. Hexagonal boron nitride (h-BN) is a promising and highly stable support material with limited applications because it is difficult to modify. In this work, a facile method for the etching of h-BN was achieved using metal oxide (MO_X) nanoparticles. The nanoporous structure of etched h-BN was revealed by selective removal of MO_X on the surface; as a result, the specific surface area and pore volume increased more than two-fold. Then, to verify the effect of the nanoporous structure, etched h-BN was used to support the catalyst because the nanoporous structure has an advantage in dispersing the nanoparticles. Fabricated etched h-BN-added catalysts exhibited high performance in N₂O conversion. This high performance was attributed to the changed oxidation states of metal cations by interaction-etched h-BN using MO_X nanoparticles. This study serves as a basis for the development of nanocomposites with various cations and supports for catalytic reaction systems. Full article

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

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16 pages, 9455 KB

Open AccessArticle

Syngas Production by Dry and Steam Reforming of a Model Biogas over Highly Active Bimetallic Co-Ir/Al₂O₃ Catalysts

by Sholpan S. Itkulova, Yerzhan Y. Nurmakanov, Yerzhan A. Boleubayev, Makpal A. Zhumash and Kuralay T. Tilegen

Catalysts 2026, 16(9), 836; https://doi.org/10.3390/catal16090836 - 17 Sep 2026

Viewed by 197

Abstract

Cobalt-based catalysts using aluminum oxide as a support and 0.025–0.10 wt.% iridium as a second metal were prepared by the impregnation method and tested in steam and dry reforming of a model biogas with a ratio of CH₄:CO₂ = 1:1. [...] Read more.

Cobalt-based catalysts using aluminum oxide as a support and 0.025–0.10 wt.% iridium as a second metal were prepared by the impregnation method and tested in steam and dry reforming of a model biogas with a ratio of CH₄:CO₂ = 1:1. The processes were carried out in a fixed bed flow reactor under atmospheric pressure with a gas hourly space velocity of 1000–1500 h⁻¹, and temperature varied in the range of 300–800 °C. The BET surface area, XRD, SEM, TEM, and H₂-TPR methods were conducted to characterize the physicochemical properties of the “fresh” and “spent” samples of catalysts. The catalysts exhibit high and stable activity in the production of syngas from the biogas. Methane was almost completely converted at 750–800 °C in the steam reforming of biogas. Stability tests over 80–100 h confirmed the catalyst’s stable operation. Syngas with a ratio of H₂/CO~0.9 is formed in dry reforming of biogas, while in steam reforming the ratio exceeds 1. It is believed that the addition of iridium to Co/Al₂O₃ causes improvement of catalyst performance due to a synergetic effect because of the interaction between Co and Ir. Full article

(This article belongs to the Special Issue 15th Anniversary of Catalysts—Advances in Catalysis for Sustainable Energy)

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20 pages, 2974 KB

Open AccessArticle

Solvent-Free Dehydrogenation of Decahydroquinoline over Palladium Nanoparticles Supported on Modified Ceria-Based Structures

by Olga Kirichenko, Elena Shuvalova, Elena Redina, Inna Ivanova, Gennady Kapustin and Leonid Kustov

Catalysts 2026, 16(9), 835; https://doi.org/10.3390/catal16090835 - 17 Sep 2026

Viewed by 379

Abstract

Hydrogen storage and transportation technologies based on liquid organic hydrogen carriers (LOHCs) are of high research interest. The next generation of LOHCs with a higher hydrogen capacity and lower dehydrogenation temperature is required, and the decahydroquinoline/quinoline (DHQ/Q) system is among promising LOHCs. The [...] Read more.

Hydrogen storage and transportation technologies based on liquid organic hydrogen carriers (LOHCs) are of high research interest. The next generation of LOHCs with a higher hydrogen capacity and lower dehydrogenation temperature is required, and the decahydroquinoline/quinoline (DHQ/Q) system is among promising LOHCs. The catalysts comprising palladium nanoparticles supported on the synthesized high-surface area materials (CeO₂, CeO₂-ZrO₂ mixed oxide, and Ce_0.75Zr_0.25O₂), as well as reverse CeO₂/Pd/oxide catalysts were tested in solvent-free dehydrogenation of DHQ at a high DHQ:Pd molar ratio, with DHQ being investigated as a hydrogen-storage source. The oxide-supported Pd nanoparticles were synthesized via the deposition–precipitation of Pd poly-hydroxo complexes, while a redox method was used to prepare the reverse catalysts. The highest hydrogen yields of 45% and 55% with the DHQ conversions of 61% and 76% at molar ratios DHQ:Pd of 1000 and 500, respectively, have been reached over the Pd/Ce_0.75Zr_0.25O₂ catalyst at 220 °C, which results in hydrogen production exceeding that of other known catalysts studied in solvent-free DHQ dehydrogenation. The challenges and prospects for further catalyst development are discussed. Full article

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

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27 pages, 9896 KB

Open AccessReview

ZSM-5 Zeolite for Catalytic Cracking of Non-Edible Oil: Strategies for Coke Suppression

by Yakun Li, Liuqi Xin, Junhao Zhi, Cong Liu, Xuzhao Yang, Liming Zhou, Miao Du and Qiaofei Zhang

Catalysts 2026, 16(9), 834; https://doi.org/10.3390/catal16090834 - 17 Sep 2026

Viewed by 426

Abstract

In the context of energy security strategies, advancing the green and low-carbon energy transition is critical for achieving the “dual carbon” goals. A key technology in this transition is the catalytic cracking of non-edible oil to produce clean biofuels, which plays a vital [...] Read more.

In the context of energy security strategies, advancing the green and low-carbon energy transition is critical for achieving the “dual carbon” goals. A key technology in this transition is the catalytic cracking of non-edible oil to produce clean biofuels, which plays a vital role in accelerating industrial restructuring and upgrading traditional energy systems. However, ZSM-5 zeolites, the most widely used catalysts in this process, commonly encounter challenges such as coke deposition and subsequent deactivation. With a focus on the underlying reaction mechanism, this review provides an in-depth analysis of the origins of coke formation and systematically explores the key influencing factors, namely the acidic properties, pore architecture, and Si/Al ratio of ZSM-5 zeolites. Furthermore, recent advances in ex situ characterization and real-time monitoring techniques for identifying coke origins, composition, and spatial distribution are summarized. Building on these insights, we detail various strategies to suppress coke deposition, including constructing hierarchical pore structures, metal doping, core–shell catalyst design, plasma catalysis, and microwave-assisted techniques. Finally, we propose perspectives and recommendations for enhancing the coking resistance of ZSM-5 zeolites. Full article

(This article belongs to the Special Issue Zeolites as Catalysts: Applications in Chemical Engineering, Energy Sources and Environmental Protection, 3rd Edition)

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17 pages, 5239 KB

Open AccessArticle

Co-Producing Reducing Sugars, Furfural and Xylooligosaccharides from Phragmites australis Straw via Efficient Pretreatment by Deep Eutectic Solvent Lactic Acid: Cetyltrimethylammonium Bromide

by Peng Chen, Zhenyao Zhao and Yu-Cai He

Catalysts 2026, 16(9), 833; https://doi.org/10.3390/catal16090833 - 16 Sep 2026

Viewed by 241

Abstract

In this work, five monocarboxylic-acid/Cetyltrimethylammonium Bromide (CTAB) solvent formulations containing formic acid, acetic acid, propionic acid, butyric acid, or lactic acid were systematically compared under identical pretreatment conditions using Phragmites australis straw (PAS) as the feedstock. The lactic acid (LA):CTAB formulation was ultimately [...] Read more.

In this work, five monocarboxylic-acid/Cetyltrimethylammonium Bromide (CTAB) solvent formulations containing formic acid, acetic acid, propionic acid, butyric acid, or lactic acid were systematically compared under identical pretreatment conditions using Phragmites australis straw (PAS) as the feedstock. The lactic acid (LA):CTAB formulation was ultimately selected for further pretreatment of PAS, because it retained substantially more of the initial glucan than formic acid (FA):CTAB, while maintaining a statistically comparable saccharification efficiency. Under the selected conditions (LA:CTAB = 4:1 mol/mol, 170 °C, 60 min), the removal rates of xylan and lignin reached 74.3% and 71.4%, respectively, while an enzymatic hydrolysis efficiency of 72.8% was acquired. In the LA:CTAB-treated liquor, xylooligosaccharides (XOS) and furfural formed in the deep eutectic solvent (DES)-pretreatment liquor contained 4.1 g/L and 1.7 g/L, respectively. Linear fitting between component removal (e.g., xylan removal and delignification) and severity factor (LogR₀) were explored. Molecular analyses of the selected LA system qualitatively indicated attractive interactions around the polar regions of lignocellulosic model compounds and possible dispersive interactions involving the alkyl chain of CTAB. These results illustrate potential noncovalent interaction modes within LA but do not establish a comparative interaction ranking among the five solvent formulations. This study offers theoretical insights into the mechanism of CTAB-based acidic DESs in biomass pretreatment and valorization and suggests a potential direction for the development of efficient and tunable pretreatment solvents for valorization of biomass and co-producing valuable biobased chemicals. Full article

(This article belongs to the Special Issue Catalysts for Biomass Conversions and Hydrogen Productions)

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23 pages, 15990 KB

Open AccessReview

Recent Advances in Donor–Acceptor Covalent Organic Frameworks for Photocatalytic H₂O₂ Production

by Jing Liang, Yiqiang Bai, Zhengyin Yan, Shangrong Wu, Wenjuan Li, Yubing Liu, Naizhang Xu and Mengyin Chen

Catalysts 2026, 16(9), 832; https://doi.org/10.3390/catal16090832 - 15 Sep 2026

Viewed by 423

Abstract

Hydrogen peroxide (H₂O₂), as a green oxidant and an emerging energy carrier, has attracted considerable attention for its photocatalytic synthesis. Covalent organic frameworks (COFs) have emerged as ideal photocatalyst platforms owing to their structurally designable nature and tunable optoelectronic [...] Read more.

Hydrogen peroxide (H₂O₂), as a green oxidant and an emerging energy carrier, has attracted considerable attention for its photocatalytic synthesis. Covalent organic frameworks (COFs) have emerged as ideal photocatalyst platforms owing to their structurally designable nature and tunable optoelectronic properties. In particular, the construction of donor–acceptor (D-A) structures has proven to be a key strategy for enhancing the photocatalytic H₂O₂ production efficiency of COFs. This review systematically summarizes the recent advances in D-A-type COFs for photocatalytic H₂O₂ production. We first elucidate the intrinsic mechanism by which D-A structures enhance photocatalytic performance, namely the promotion of exciton dissociation and charge separation via intramolecular charge transfer effects. Subsequently, we provide a comprehensive assessment of strategies for optimizing the photocatalytic performance of D-A COFs, including D-A architecture design (encompassing D-A, D-π-A, A-D-A variants, and others), linkage engineering, functional group modification, dimensionality and topology modulation, and heterojunction construction. Finally, we critically analyze the current shortcomings in stability, mechanistic understanding, scalable synthesis, and practical applications, and offer perspectives on future research directions. This review aims to provide a systematic reference for the rational design of high-performance D-A-type COF photocatalysts. Full article

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

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28 pages, 12620 KB

Open AccessReview

Covalent Triazine Frameworks for Lithium–Sulfur Batteries: Confinement, Catalysis, and Redox Mediation

by Wanyu Ye, Yicheng Qian, Wen Luo, Yifan Zhang and Yang Wu

Catalysts 2026, 16(9), 831; https://doi.org/10.3390/catal16090831 - 15 Sep 2026

Viewed by 338

Abstract

Lithium–sulfur (Li–S) batteries offer high theoretical specific energy and low-cost sulfur chemistry, but their practical application is limited by polysulfide shuttle, the electronic insulation of sulfur and Li₂S, and sluggish liquid–solid and solid–liquid conversion. Covalent triazine frameworks (CTFs) combine nitrogen-rich pore [...] Read more.

Lithium–sulfur (Li–S) batteries offer high theoretical specific energy and low-cost sulfur chemistry, but their practical application is limited by polysulfide shuttle, the electronic insulation of sulfur and Li₂S, and sluggish liquid–solid and solid–liquid conversion. Covalent triazine frameworks (CTFs) combine nitrogen-rich pore walls, tunable porosity, chemical robustness, and molecular designability, making them promising platforms for regulating sulfur species. This review focuses on strictly defined CTFs and closely related CTF-derived systems used in Li–S batteries. Rather than treating polysulfide adsorption or improved cycling as evidence of catalysis, the functional roles of CTFs are separated into confinement, catalysis, and redox mediation, while the strength of mechanistic evidence is evaluated independently. Representative sulfur hosts, conductive hybrids, functional separators, and redox-active CTFs are compared with emphasis on Li₂S nucleation and growth, deposition morphology, sulfur-conversion kinetics, direct Li₂S precipitation/decomposition tests, and practical cell parameters. The analysis identifies balanced polysulfide affinity, electronic connectivity, wet-state pore accessibility, active-site attribution, and framework stability as key structure–activity descriptors. Future progress requires rigorous mechanistic controls, scalable and sustainable synthesis, and testing under high-sulfur-loading and lean-electrolyte conditions. CTFs are therefore best regarded as molecularly tunable platforms for verifiable sulfur-redox regulation rather than universal catalysts. Full article

(This article belongs to the Special Issue Nanostructured Materials: Advancing Photocatalysis and Electrocatalysis for Future Technologies)

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21 pages, 10857 KB

Open AccessArticle

Investigating the Combined Effect of Ultrasound and an Iron Oxide Catalyst for the Degradation of Congo Red Dye

by Khursheed B. Ansari

Catalysts 2026, 16(9), 830; https://doi.org/10.3390/catal16090830 - 15 Sep 2026

Viewed by 328

Abstract

Industrial dyes remain a major source of water pollution and pose environmental and human health risks because of their carcinogenic and mutagenic properties. Of these, Congo Red dye shows high toxicity and stability in aquatic environments; therefore, removing it from water bodies is [...] Read more.

Industrial dyes remain a major source of water pollution and pose environmental and human health risks because of their carcinogenic and mutagenic properties. Of these, Congo Red dye shows high toxicity and stability in aquatic environments; therefore, removing it from water bodies is desirable. Among numerous methods, ultrasound-assisted catalysis for dye degradation remains promising. This work investigates the combined effect of ultrasound and an iron oxide (Fe₂O₃) catalyst for degrading Congo Red (CR) dye (a model industrial dye). The characterization of Fe₂O₃ particles was performed through SEM, XRD, and FTIR analyses. CR degradation was performed at 100–600 W ultrasound power, 0–120 min, and with 5–20% (w/v) Fe₂O₃. The ultrasound-driven CR degradation was compared with and without the Fe₂O₃ catalyst. Using ultrasound alone, maximum CR degradation reached 39.30%, while adding Fe₂O₃ (20% w/v) during ultrasonication enabled 93.20% CR degradation in 120 min. The optimized conditions for maximum CR degradation (93.21%) were 600 W, 30 °C, 120 min, and 20% w/v Fe₂O₃. The enhancement was attributed to acoustic cavitation, heterogeneous bubble nucleation on Fe₂O₃ surfaces, improved mass transfer, Fe³⁺/Fe²⁺ redox cycling, and reactive oxygen species generation. Further, the kinetic analysis indicated that the CR degradation followed a pseudo-second-order kinetic model, showing strong agreement with experimental data (R² = 0.96). A detailed mechanism was proposed involving CR adsorption, azo-bond cleavage, aromatic ring hydroxylation, fragmentation, ring opening, and progressive oxidation into smaller intermediates. Overall, the present study demonstrates that ultrasound combined with Fe₂O₃ effectively enhanced Congo Red removal/decolorization under the investigated laboratory-scale conditions. Full article

(This article belongs to the Special Issue Design and Application of Combined Catalysis, 2nd Edition)

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17 pages, 13389 KB

Open AccessArticle

Influence of Nitrogen Donor Type on Electrocatalytic Performance of Copper Complexes: A Detailed Theoretical Analysis of Experimental Results

by Alan Mendieta, J. Raúl Álvarez-Idaboy, Víctor M. Ugalde-Saldívar and Laura Gasque

Catalysts 2026, 16(9), 829; https://doi.org/10.3390/catal16090829 - 14 Sep 2026

Viewed by 276

Abstract

In this work, the electroreduction of molecular oxygen was studied using Cu(II) complexes with two slightly different ligands: one pyridine-based (dpba) and the other imidazole-based (dipa). Cyclic voltammetry in MeOH/H₂O at pH = 9 showed that Cu [...] Read more.

In this work, the electroreduction of molecular oxygen was studied using Cu(II) complexes with two slightly different ligands: one pyridine-based (dpba) and the other imidazole-based (dipa). Cyclic voltammetry in MeOH/H₂O at pH = 9 showed that Cu^IIdpba exhibits higher redox reversibility and better-defined oxidation peaks than Cu^IIdipa, indicating faster electron-transfer kinetics and more efficient regeneration of the reduced species. In the presence of atmospheric O₂, Cu^IIdpba produced higher cathodic currents, indicating superior electrocatalytic activity. Scan-rate-dependent studies revealed the formation of a Cu(II)–O₂ intermediate, whose accumulation depends on the ligand type and timescale. Foot-of-the-Wave Analysis (FOWA) yielded a k_obs of 33.43 s⁻¹ for Cu^IIdpba, compared to 0.10 s⁻¹ for Cu^IIdipa, confirming the pyridine-based system’s higher kinetic efficiency. DFT calculations indicated that Cu^IIdpba maintains a stable geometry upon reduction, facilitating O₂ interaction, while Cu^IIdipa undergoes distortions, forming less reactive Cu(II)–O₂ adducts. Frontier orbital and electrostatic potential analyses revealed that the stronger π-acceptor character of dpba enhances Cu(I) polarization and long-range electron transfer, unlike dipa. These results demonstrate that ligand electronics critically control the electrocatalytic oxygen reduction activity, thereby explaining the superior performance of the pyridine-based Cu(II) complex. Full article

(This article belongs to the Special Issue Young Researchers in Electrocatalysis)

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37 pages, 11531 KB

Open AccessReview

Intelligent Hierarchical Micro–Mesoporous Nanoarchitectures: Engineering Pore Connectivity and Active-Site Cooperativity for Multifunctional Catalytic Systems

by Shuayl Alotaibi, Awad M. Bakry, Lamiaa S. El-Sherif and Safwat Hassaballa

Catalysts 2026, 16(9), 828; https://doi.org/10.3390/catal16090828 - 13 Sep 2026

Viewed by 262

Abstract

Hierarchical porous catalysts now benefit from intentional co-design of transport pathways and catalytic functionality. This review critically examines intelligent micro–mesoporous nanoarchitectures, emphasizing pore connectivity and active-site cooperativity as inseparable design principles. We first outline limitations of purely microporous systems (diffusion constraints, site inaccessibility, [...] Read more.

Hierarchical porous catalysts now benefit from intentional co-design of transport pathways and catalytic functionality. This review critically examines intelligent micro–mesoporous nanoarchitectures, emphasizing pore connectivity and active-site cooperativity as inseparable design principles. We first outline limitations of purely microporous systems (diffusion constraints, site inaccessibility, deactivation) and then show how multi-scale networks overcome these issues. Engineering strategies for pore connectivity involving bottom-up templating, post-synthetic reconstruction, top-down desilication/dealumination are systematically reviewed alongside metrics (tortuosity, connectivity, accessibility). Active-site cooperativity is examined via acid-based bifunctionality, metal-acid coupling, single-atom catalysis and compartmentalized architectures for cascade reactions. The central thesis is that optimal performance emerges when transport and catalytic site engineering are coupled, supported by evidence from zeolites, metal–organic frameworks, silica nanoreactors, heteroatom-doped carbons and advanced electrocatalysts. Applications include biomass upgrading, selective oxidation, and energy conversion. The review also covers stability, deactivation, and regeneration, suggests standardized reporting criteria, and highlights future challenges such as using AI for catalyst design, operando transport mapping, scalable catalyst synthesis, and programmable catalytic nanoarchitectures. This review offers a predictive design strategy for next-generation multifunctional catalytic materials by focusing on the integrated transport-reaction system instead of only focusing on the structure. Full article

(This article belongs to the Special Issue Microporous and Mesoporous Materials for Catalytic Applications, 2nd Edition)

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8 pages, 209 KB

Open AccessEditorial

Enzyme and Biocatalysis Application

by Chia-Hung Kuo, Chwen-Jen Shieh and Yung-Chuan Liu

Catalysts 2026, 16(9), 827; https://doi.org/10.3390/catal16090827 - 12 Sep 2026

Viewed by 218

Abstract

Enzymes have emerged as powerful biocatalysts for addressing the growing demand for efficient, selective, and sustainable chemical and biochemical processes [...] Full article

(This article belongs to the Special Issue Enzyme and Biocatalysis Application)

16 pages, 1384 KB

Open AccessArticle

Display of Linoleic Acid Isomerase on Bacillus subtilis Spores for Bioconversion of Linoleic Acid to t10,c12-Conjugated Linoleic Acid

by Saranya Nallapareddy, Adriana Botes, Ivan Mijakovic and Carsten Jers

Catalysts 2026, 16(9), 826; https://doi.org/10.3390/catal16090826 - 12 Sep 2026

Viewed by 354

Abstract

Conjugated linoleic acid (CLA) comprises positional and geometric isomers of linoleic acid (LA) that have attracted interest due to their reported biological activities. In particular, trans-10,cis-12-CLA (t10,c12-CLA) has been associated with distinct metabolic effects, but its selective production remains challenging because conventional chemical [...] Read more.

Conjugated linoleic acid (CLA) comprises positional and geometric isomers of linoleic acid (LA) that have attracted interest due to their reported biological activities. In particular, trans-10,cis-12-CLA (t10,c12-CLA) has been associated with distinct metabolic effects, but its selective production remains challenging because conventional chemical synthesis generates mixtures of CLA isomers. In this study, the linoleic acid isomerase from Propionibacterium acnes (PAI) was displayed on Bacillus subtilis spores by fusion to spore crust proteins to develop a biocatalyst for t10,c12-CLA production. Twenty-four recombinant B. subtilis strains were constructed by fusing PAI to six spore crust proteins with different linker architectures. All constructs produced detectable t10,c12-CLA from 5 mg/mL LA, demonstrating that spore-displayed PAI remained catalytically active and accessible to extracellular substrate. The CgeA-L2 construct showed the highest mean CLA production, approximately 1.33 mg/mL CLA under the tested conditions. Time-course experiments revealed that product formation increased during the initial phase of the reaction before reaching a plateau, while recovered spores retained catalytic activity after one reuse cycle. Finally, spore-displayed PAI converted LA released from safflower oil by soluble lipase. Together, these results establish B. subtilis spores as a functional display format for PAI and provide a basis for further development of a recoverable catalyst for CLA production. Full article

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

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40 pages, 18508 KB

Open AccessReview

Mechanistic Insights and Design Principles for Catalytic Interface Engineering in Water Electrolysis

by Minsu Kim, Rakchan Kim, Jinkyu Park and Seonggyu Lee

Catalysts 2026, 16(9), 825; https://doi.org/10.3390/catal16090825 - 12 Sep 2026

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Abstract

Water electrolysis is a key technology for renewable hydrogen production, yet its efficiency and durability remain constrained by the multistep kinetics of the hydrogen and oxygen evolution reactions and by catalyst degradation under operating conditions. Interface engineering has emerged as a powerful strategy [...] Read more.

Water electrolysis is a key technology for renewable hydrogen production, yet its efficiency and durability remain constrained by the multistep kinetics of the hydrogen and oxygen evolution reactions and by catalyst degradation under operating conditions. Interface engineering has emerged as a powerful strategy for addressing these limitations by regulating local electronic structures, adsorption energetics, intermediate transport, and structural evolution at heterointerfaces. This review presents a mechanistic perspective on interface-engineered electrocatalysts by organizing recent advances according to the elementary steps and reaction pathways regulated by catalytic interfaces, rather than by catalyst composition or material class. Particular emphasis is placed on how interfacial charge redistribution, complementary active sites, intermediate migration, and dynamic structural evolution collectively govern catalytic activity and stability. Across these studies, effective interfaces must coordinate multiple kinetic and thermodynamic functions while preserving structural integrity and accessibility under relevant operating conditions. Key challenges arise from the dynamic and heterogeneous nature of working interfaces and the persistent gap between intrinsic catalyst activity and device-level performance. This review establishes mechanistic design principles for developing efficient, durable, and practically relevant interface-engineered electrocatalysts for water electrolysis. Full article

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

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40 pages, 21840 KB

Open AccessReview

Catalytic Annulations of Itaconimides: Mechanistic Diversity and Opportunities for More Sustainable Organic Synthesis

by Mohammad Aslam, Priyanka Raju Thombal, Seho Sun and Muhammad Saeed Akhtar

Catalysts 2026, 16(9), 824; https://doi.org/10.3390/catal16090824 - 12 Sep 2026

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Abstract

Itaconimides combine an electron-deficient terminal methylene group with a succinimide framework, creating a reactive topology that differs from those of maleimides, citraconimides, and substituted α-alkylidene succinimides. This review critically examines annulation reactions of terminal-methylene itaconimides, defined here as 3-methylenepyrrolidine-2,5-diones bearing an unsubstituted =CH [...] Read more.

Itaconimides combine an electron-deficient terminal methylene group with a succinimide framework, creating a reactive topology that differs from those of maleimides, citraconimides, and substituted α-alkylidene succinimides. This review critically examines annulation reactions of terminal-methylene itaconimides, defined here as 3-methylenepyrrolidine-2,5-diones bearing an unsubstituted =CH₂ group. Catalyst-free and reagent-promoted transformations are first considered as benchmarks for intrinsic reactivity, followed by organocatalytic, nucleophilic phosphine-catalysed, transition-metal-catalysed, and visible-light photoredox processes. Across these reaction classes, the exocyclic alkene functions as a dipolarophile, electrophilic addition site, radical acceptor, or migratory-insertion partner, while catalyst structure and reaction environment govern the subsequent fate of the resulting intermediates. A recurring feature is therefore that catalysis often controls reaction pathway and selectivity, rather than merely enabling alkene activation, allowing divergent access to spirocyclic, fused, and polycyclic products and, in selected cases, high regio-, diastereo-, or enantioselectivity. At the same time, substrate generality remains uneven, with several studies examining only limited variation of the itaconimide component or isolated terminal-methylene examples within broader α-alkylidene succinimide series. Quantitative information on catalyst efficiency, material demand, energy input, and preparative performance is also scarce. These gaps define opportunities for broader substrate validation, stronger mechanistic interrogation, and more rigorous process evaluation in the future development of selective and sustainable itaconimide annulations. Full article

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

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31 pages, 9173 KB

Open AccessReview

Recent Advances in MOF-Derived PGM-Free ORR Catalysts: From Active-Site Engineering to Working Cathodes

by Quoc Hao Nguyen, Huyen Thi Dao and Jinsoo Kim

Catalysts 2026, 16(9), 823; https://doi.org/10.3390/catal16090823 - 11 Sep 2026

Viewed by 446

Abstract

The oxygen reduction reaction (ORR) remains a major bottleneck in terms of kinetics and durability in fuel cells and zinc–air batteries (ZABs). Metal–organic frameworks (MOFs) are versatile precursors for platinum-group metal (PGM)-free ORR electrocatalysts because their metal distribution, ligand chemistry, guest confinement, morphology, [...] Read more.

The oxygen reduction reaction (ORR) remains a major bottleneck in terms of kinetics and durability in fuel cells and zinc–air batteries (ZABs). Metal–organic frameworks (MOFs) are versatile precursors for platinum-group metal (PGM)-free ORR electrocatalysts because their metal distribution, ligand chemistry, guest confinement, morphology, and porosity can be controlled before pyrolysis. This review examines how these precursor characteristics and subsequent thermal conversion govern metal migration; heteroatom retention; carbon ordering; pore evolution; and, ultimately, the nuclearity, coordination environment, and accessibility of the resulting active sites. Recent advances in conventional and asymmetric M–N_x single-atom sites, dual- and multi-atom sites, and single-atom–cluster or nanophase interfaces are critically evaluated, with particular attention to the evidence supporting structural assignments, activity, selectivity, and durability. Half-cell performance is further related to practical fuel-cell and ZAB operation by considering catalyst loading, ionomer or electrolyte contact, gas and water transport, and catalyst-layer degradation. Further progress will require simultaneous optimization of active-site structure, accessible-site density, hierarchical porosity, carbon stability, and electrode architecture, together with standardized testing protocols for reliable translation from rotating disk electrode measurements to working cathodes. Full article

(This article belongs to the Special Issue Feature Review Papers in Electrocatalysis, 2nd Edition)

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23 pages, 20098 KB

Open AccessArticle

S-CoAl-LDH/Fe-C₃N₅ Heterojunction for the Efficient Photocatalytic Reduction of Cr(VI) and Degradation of Tetracycline Complex Pollutants

by Meilan Li, Wei Gong, Jiayi Dong, Chenghui Pei, Liangliang Chang and Shan Xu

Catalysts 2026, 16(9), 822; https://doi.org/10.3390/catal16090822 - 11 Sep 2026

Viewed by 341

Abstract

Heterojunction construction is a key strategy for enhancing the photocatalytic efficiency of semiconductors. In this study, a composite of sulfur-doped CoAl layered double hydroxide and Fe-doped C₃N₅(S-CoAl-LDH/Fe-C₃N₅) was developed via a hydrothermal method for the [...] Read more.

Heterojunction construction is a key strategy for enhancing the photocatalytic efficiency of semiconductors. In this study, a composite of sulfur-doped CoAl layered double hydroxide and Fe-doped C₃N₅(S-CoAl-LDH/Fe-C₃N₅) was developed via a hydrothermal method for the synergistic oxidation-reduction degradation of the organic pollutant tetracycline (TC) and the detoxification of heavy-metal ions (Cr(VI)) in wastewater. After optimization, the CAF-4 heterojunction (the composite with 20 wt% Fe-C₃N₅ loading) exhibited TC degradation rates 5.51 and 3.97 times higher than those of pristine Fe-C₃N₅ and S-CoAl-LDH, respectively; under simulated sunlight, the Cr(VI) reduction rates were 11.75 and 4.22 times higher, respectively. The as-prepared catalyst demonstrated good stability across a wide pH range, in the presence of various cations and anions, and in different water matrices. Under coexisting pollutant conditions, the composite still achieved removal efficiencies of 82.1% for Cr(VI) and 64.7% for TC. After five cycling runs, the adsorption-photocatalytic efficiency of the composite for the removal of Cr(VI) and TC composite pollutants remained above 80%. Overall, CAF-4 shows great promise for application in the adsorption-photocatalytic treatment of wastewater containing combined Cr(VI) and TC pollution. Full article

(This article belongs to the Section Photocatalysis)

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