Catalysts

16 pages, 3804 KB

Open AccessArticle

Design and Optimization of Trimetallic NiCoFe Catalysts for Efficient Dry Reforming of Methane

by Ghazaleh Khoshroo, Anastasiia Efremova, Haythem S. Basheer, Imre Szenti, Masoud Shirzadi Ahou Dashti, Ákos Szamosvölgyi, András Erdőhelyi, András Sápi, Ákos Kukovecz and Zoltán Kónya

Catalysts 2025, 15(8), 797; https://doi.org/10.3390/catal15080797 - 21 Aug 2025

Viewed by 526

Abstract

Dry reforming of methane is an advantageous technique to produce syngas by using greenhouse gases like CO₂ and CH₄. This study investigated the stability, catalytic effectiveness, and physicochemical characteristics of mono- and trimetallic catalysts based on Ni and supported on [...] Read more.

Dry reforming of methane is an advantageous technique to produce syngas by using greenhouse gases like CO₂ and CH₄. This study investigated the stability, catalytic effectiveness, and physicochemical characteristics of mono- and trimetallic catalysts based on Ni and supported on γ-Al₂O₃. Adding Co and Fe has been found to modify the structure and surface through the characterizations, including XRD, SEM, TEM, BET, H₂-TPR, and XPS methods. Compared to the monometallic Ni catalyst, the trimetallic catalysts exhibited improved alloy formation, reduced particle size, increased metal dispersion, and enhanced surface area and pore structures. The 10% Ni, 2.5% Co, and 2.5% Fe-Al₂O₃ catalyst exhibits higher CH₄ conversion, surpassing 75%, and also CO₂ conversion around 85% at 700 °C, compared to 15% Ni-Al₂O₃, which showed CH₄ conversion of about 65% and CO₂ conversion of 70%. It also showed comparatively good stability in 24 h testing performed at 700 °C. According to the findings of the research on trimetallic catalysts, their capacity to improve dry reforming of methane (DRM) performance may be attributed to increased stability, which is a crucial challenge in the production of sustainable syngas, as well as higher activity and lower deactivation. Full article

(This article belongs to the Section Catalysis for Sustainable Energy)

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12 pages, 2787 KB

Open AccessArticle

Rapid Biodecolorization of Azo Dyes by Shewanella oneidensis MR-1 Under Aerobic Conditions

by Yuelei Wang, Yuqi Liu, Xiaojun Zhang, Lu Cheng, Daizong Cui, Min Zhao and Xianchun Zong

Catalysts 2025, 15(8), 796; https://doi.org/10.3390/catal15080796 - 21 Aug 2025

Viewed by 540

Abstract

This study investigated the aerobic biodecolorization of azo dyes by Shewanella oneidensis MR-1. S. oneidensis MR-1 can rapidly degrade azo dyes under aerobic conditions, even at high concentrations of up to 270 mg/L, demonstrating remarkable dye decolorization capabilities. This decolorization efficiency persists even [...] Read more.

This study investigated the aerobic biodecolorization of azo dyes by Shewanella oneidensis MR-1. S. oneidensis MR-1 can rapidly degrade azo dyes under aerobic conditions, even at high concentrations of up to 270 mg/L, demonstrating remarkable dye decolorization capabilities. This decolorization efficiency persists even under high concentrations of oxygen. The introduction of different environmental metal ions led to either inhibitory or stimulatory effects on the decolorization of Methyl Orange and Amaranth. Furthermore, the addition of extracellular electron shuttles and electron scavengers confirmed that dyes were being reduced via electron transfer, and the decolorization capability of S. oneidensis MR-1 correlated with electron density. Our study unveils the rapid degradation ability of S. oneidensis MR-1 for dyes under aerobic conditions, which is closely linked to its electron transfer capacity. This research holds significant implications for a deeper understanding of the biodegradation mechanisms of azo dyes under aerobic conditions. Full article

(This article belongs to the Section Biocatalysis)

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21 pages, 4856 KB

Open AccessArticle

High-Pressure Catalytic Ethanol Reforming for Enhanced Hydrogen Production Using Efficient and Stable Nickel-Based Catalysts

by Feysal M. Ali, Pali Rosha, Karen Delfin, Dean Hoaglan, Robert Rapier, Mohammad Yusuf and Hussameldin Ibrahim

Catalysts 2025, 15(8), 795; https://doi.org/10.3390/catal15080795 - 21 Aug 2025

Viewed by 651

Abstract

The urgent need to address the climate crisis demands a swift transition from fossil fuels to renewable energy. Clean hydrogen, produced through ethanol steam reforming (ESR), offers a viable solution. Traditional ESR operates at atmospheric pressure, requiring costly separation and compression of hydrogen. [...] Read more.

The urgent need to address the climate crisis demands a swift transition from fossil fuels to renewable energy. Clean hydrogen, produced through ethanol steam reforming (ESR), offers a viable solution. Traditional ESR operates at atmospheric pressure, requiring costly separation and compression of hydrogen. High-pressure ESR, however, improves hydrogen purification, streamlines processes like pressure swing adsorption, and reduces operational costs while enhancing energy efficiency. High-pressure ESR also enables compact reactor designs, minimizing equipment size and land use by compressing reactants into smaller volumes. This study evaluates two nickel-based commercial catalysts, AR-401 and NGPR-2, under high-pressure ESR conditions. Key parameters, including reaction temperature, steam-to-ethanol ratio, and weight hourly space velocity, were optimized. At 30 bars, 700 °C, and a steam-to-ethanol ratio of 9, both catalysts demonstrated complete ethanol conversion, with hydrogen selectivity of 65–70% and yields of 4–4.5 moles of H₂ per mole of ethanol. Raising the temperature to 850 °C improved hydrogen selectivity to 74% and yielded 5.2 moles of H₂ per mole. High-pressure ESR using renewable ethanol provides a scalable, efficient pathway for hydrogen production, supporting sustainable energy solutions. Full article

(This article belongs to the Special Issue Catalytic Reforming and Hydrogen Production: From the Past to the Future, 2nd Edition)

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17 pages, 3298 KB

Open AccessFeature PaperArticle

Synthesis of Niacin from 3-Cyanopyridine with Recombinant Escherichia coli Carrying afnitA Nitrilase in a Deep Eutectic Solvent System

by Jingyi Zhou, Bo Fan, Wenyan Fan and Yucai He

Catalysts 2025, 15(8), 794; https://doi.org/10.3390/catal15080794 - 20 Aug 2025

Viewed by 570

Abstract

Niacin is a compound with a wide range of applications in pharmaceuticals, healthcare, food nutrition, animal breeding, cosmetics, etc. A recombinant Escherichia coli carrying the afnitA nitrilase gene was created to transform 3-cyanopyridine into niacin in this work. After analyzing the viscosity, surface [...] Read more.

Niacin is a compound with a wide range of applications in pharmaceuticals, healthcare, food nutrition, animal breeding, cosmetics, etc. A recombinant Escherichia coli carrying the afnitA nitrilase gene was created to transform 3-cyanopyridine into niacin in this work. After analyzing the viscosity, surface tension, and Kamlet-Taft (K-T) parameters (π*, α, and β values) of certain deep eutectic solvents (DESs), Betaine:Acetic Acid (Betaine:AA) (1:2, mol/mol) was chosen as the bioreaction medium. Using response surface methodology (RSM), systematic biocatalytic optimization was performed. The optimum medium pH, cell loading, temperature, and DES (Betaine:AA) (1:2, mol/mol) dose were determined to be 7.75, 195 g/L, 44.24 °C, and 18.04 wt%. Under the optimized conditions, whole-cell catalysis facilitated the conversion of 3-cyanopyridine to niacin, achieving a high yield of 98.6% within 40 min. These results demonstrated that recombinant E. coli carrying the afnitA nitrilase gene may have practical value as a biocatalyst for the production of niacin, with promising prospects for future applications. Full article

(This article belongs to the Special Issue Catalytic Procedures for the Synthesis of Pharmaceutical Active Compounds in Deep Eutectic Solvents)

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48 pages, 2448 KB

Open AccessReview

ZnO-Based Photocatalysts: Synergistic Effects of Material Modifications and Machine Learning Optimization

by Sanja J. Armaković, Stevan Armaković, Andrijana Bilić and Maria M. Savanović

Catalysts 2025, 15(8), 793; https://doi.org/10.3390/catal15080793 - 20 Aug 2025

Viewed by 889

Abstract

ZnO-based photocatalysts have attracted significant attention for their potential use in advanced oxidation processes for environmental remediation. However, critical challenges, such as rapid charge carrier recombination and narrow light absorption, and poor long-term stability necessitate material modifications to enhance performance. This review provides [...] Read more.

ZnO-based photocatalysts have attracted significant attention for their potential use in advanced oxidation processes for environmental remediation. However, critical challenges, such as rapid charge carrier recombination and narrow light absorption, and poor long-term stability necessitate material modifications to enhance performance. This review provides a comprehensive and critical analysis of recent developments in ZnO-based photocatalysts, including heterojunctions with metal oxides, carbon-based hybrids, metal/non-metal doping, and metal–organic framework materials. Furthermore, emerging trends, such as the integration of atomistic calculations and machine learning (ML) techniques in material design, property prediction, and the optimization of photocatalytic performance, are critically examined. These modern computationally driven approaches provide new insights into band gap engineering, charge transport mechanisms, and the optimization of synthesis parameters, thereby accelerating the discovery of high-performance ZnO-based photocatalysts. However, their practical integration remains limited due to the availability of high-quality datasets and the lack of interdisciplinary methodologies. The review also discusses key research gaps, including emerging environmental applications, as well as stability and scalability challenges, providing a roadmap for future research in data-driven photocatalysis. By evaluating current research, this review aims to provide a foundation for the modification of next-generation ZnO-based photocatalysts for environmental applications. Full article

(This article belongs to the Special Issue Advances in Sustainable Remediation Technologies: Advanced Oxidation, Catalytic Nanomaterials, and Computational Modeling)

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19 pages, 6279 KB

Open AccessArticle

Enhancing the Production of Thermostable Mangrovibacter plantisponsor Xylanase for Application in Breadmaking

by Wafa A. Alshehri, Ebtihal M. Alharbi, Bilel Hadrich, Ashjan F. Khalel, Fatimah S. Alqahtani, Yaaser Q. Almulaiky and Adel Sayari

Catalysts 2025, 15(8), 792; https://doi.org/10.3390/catal15080792 - 20 Aug 2025

Viewed by 595

Abstract

Xylanase was isolated from a newly isolated Mangrovibacter plantisponsor UMTKB-3 strain. The response surface methodology was employed to optimize extracellular xylanase production; the best experimental value (25 ± 0.12 U/mL) was obtained when using 16 g/L of tryptone, 15 g/L of yeast extract, [...] Read more.

Xylanase was isolated from a newly isolated Mangrovibacter plantisponsor UMTKB-3 strain. The response surface methodology was employed to optimize extracellular xylanase production; the best experimental value (25 ± 0.12 U/mL) was obtained when using 16 g/L of tryptone, 15 g/L of yeast extract, 15 g/L of NaCl, and an initial optical density of 0.2 at 600 nm. The optimized xylanase production was enhanced by five-fold compared to the pre-optimized conditions. Maximum xylanase activity was measured at 50 °C and pH 6, using xylan as the substrate. The enzyme maintained more than 98.9% of its initial activity at temperatures ranging from 45 to 60 °C. Xylanase exhibited a higher stability in the presence of metal ions: residual activities of 190%, 97.1%, and 81.1% were measured in the presence of MnCl₂, FeSO₄, and NiCl₂, respectively. Moreover, the application of M. plantisponsor xylanase to improve bread quality was investigated. The rate of increase in firmness during storage was lower in xylanase-supplemented bread compared with control bread. Supplementing the bread with xylanase resulted in increased elasticity and extensibility, as well as an increase in volume and a decrease in density. These findings suggest that our enzyme is a promising candidate for food industry applications, particularly in the baking industry, for promoting human health. Full article

(This article belongs to the Special Issue New Trends in Industrial Biocatalysis, 2nd Edition)

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26 pages, 3695 KB

Open AccessFeature PaperReview

Metal-Modified Zeolites for Catalytic Dehydration of Bioethanol to Ethylene: Mechanisms, Preparation, and Performance

by Hailong Ma, Shiwen Zhang, Hui Gao and Dongsheng Wen

Catalysts 2025, 15(8), 791; https://doi.org/10.3390/catal15080791 - 20 Aug 2025

Viewed by 687

Abstract

With increasing demands for sustainable chemical production, bioethanol-derived ethylene offers a promising alternative to petroleum-based routes. This review examines recent advances in metal-modified zeolites for the catalytic conversion of bioethanol to ethylene. The fundamental reaction mechanisms and preparation methodologies are systematically analysed. Various [...] Read more.

With increasing demands for sustainable chemical production, bioethanol-derived ethylene offers a promising alternative to petroleum-based routes. This review examines recent advances in metal-modified zeolites for the catalytic conversion of bioethanol to ethylene. The fundamental reaction mechanisms and preparation methodologies are systematically analysed. Various metal modification strategies are discussed alongside their effects on catalyst properties. The influence of zeolite framework characteristics, metal species selection, and reaction parameters on catalytic performance are evaluated. Detailed attention is given to deactivation mechanisms and strategies for catalyst regeneration and lifetime extension. The analysis provides insights into rational catalyst design for sustainable ethylene production, highlighting opportunities for future research in enhancing catalyst stability and efficiency. Full article

(This article belongs to the Special Issue Sustainable Catalysis for Green Chemistry and Energy Transition, 2nd Edition)

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13 pages, 3611 KB

Open AccessArticle

Surfactant-Assisted Catalyst Ink Dispersion for Enhanced Cell Performance of Proton Exchange Membrane Fuel Cells

by Jaeyoung Kim, Dong-Hyun Lee, Hyun-Soo Kim, Gyungse Park, In-Tae Kim, Md. Masud Rana, Hyoung-Juhn Kim, Ho-Jung Sun and Joongpyo Shim

Catalysts 2025, 15(8), 790; https://doi.org/10.3390/catal15080790 - 19 Aug 2025

Viewed by 630

Abstract

This study examines the effects of several commercial surfactants on the dispersion of catalyst inks for proton exchange membrane fuel cells (PEMFCs). Catalyst inks containing Pt/C were spray-coated and assembled into membrane electrode assemblies (MEAs) by hot pressing. The structural and electrochemical properties [...] Read more.

This study examines the effects of several commercial surfactants on the dispersion of catalyst inks for proton exchange membrane fuel cells (PEMFCs). Catalyst inks containing Pt/C were spray-coated and assembled into membrane electrode assemblies (MEAs) by hot pressing. The structural and electrochemical properties of the resulting catalyst layers were characterized through particle size analysis, zeta potential measurements, contact angle determinations, and single-cell performance tests. Among the formulations evaluated, the ink with non-ionic surfactant Triton X-100 (TX) delivered the best performance, achieving a current density of 1134 mA/cm² at 0.3 V—substantially higher than that of the surfactant-free control. These findings provide practical guidance for selecting appropriate surfactants to optimize catalyst-ink preparation and enhance PEMFC performance. Full article

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

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12 pages, 4939 KB

Open AccessArticle

Engineering Malic Enzyme CO₂ Fixation Activity via a Structure–Sequence–SCANNER (3S) Co-Evolution Strategy

by Jianping Shi, Mingdong Wang, Ting Feng, Xianglong Li, Yanbin Feng and Song Xue

Catalysts 2025, 15(8), 789; https://doi.org/10.3390/catal15080789 - 18 Aug 2025

Viewed by 581

Abstract

Enzymatic CO₂ fixation offers great potential for the sustainable synthesis of value-added compounds. Malic enzyme (ME) catalyzes the reverse carboxylation of pyruvate to malate, enabling direct CO₂ conversion into C₄ compounds with broad biosynthetic applications. However, the reverse carboxylation activity [...] Read more.

Enzymatic CO₂ fixation offers great potential for the sustainable synthesis of value-added compounds. Malic enzyme (ME) catalyzes the reverse carboxylation of pyruvate to malate, enabling direct CO₂ conversion into C₄ compounds with broad biosynthetic applications. However, the reverse carboxylation activity of wild-type ME is insufficient, and conventional enzyme engineering strategies remain limited by the complexity of identifying distal functional sites. Here, we present a Structure–Sequence–SCANNER (3S) co-evolution strategy that integrates protein structural analysis, sequence conservation profiling, and co-evolutionary network analysis to enable systematic identification of functionally relevant hotspot residues. Using this approach, we engineered Escherichia coli ME (EcME) variants with enhanced CO₂ fixation activities. In total, 106 single-point variants were constructed and screened. Among these, variants A464S and D97E exhibited significantly improved reverse carboxylation activities, with 1.7-fold and 1.6-fold increases in catalytic activity and 1.5-fold and 1.8-fold improvements in catalytic efficiency (k_cat/K_m), respectively, compared to wild-type EcME. Their catalytic efficiencies (k_cat/K_m) improved by 1.5-fold and 1.8-fold, increasing from 80 mM⁻¹·min⁻¹ for the wild-type enzyme to 120 and 130 mM⁻¹·min⁻¹, respectively. Mechanistic analyses revealed that A464S introduces a stabilizing hydrogen bond with N462, enhancing NADPH binding, while D97E forms a new salt bridge network with K513, resulting in contraction of the substrate pocket entrance and increased pyruvate affinity. These findings demonstrate the effectiveness of the 3S strategy in reprogramming enzyme functions and highlight its potential for constructing efficient artificial CO₂ fixation systems. Full article

(This article belongs to the Section Biocatalysis)

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12 pages, 2284 KB

Open AccessArticle

Metal-Free Cellulose Carbon Nanofiber Supported Graphitic Carbon Nitride for High-Efficient BPA Degradation by Photcatalytic Peroxymonosulfate Activation

by Jingjing Liu, Guilong Gao and Lu Gan

Catalysts 2025, 15(8), 788; https://doi.org/10.3390/catal15080788 - 18 Aug 2025

Viewed by 562

Abstract

Herein, carbon nanofiber (CNF) was prepared by pyrolyzing electrospun cellulose nanofiber, which was further used to incorporate with graphitic carbon nitride (g-C₃N₄) to prepare metal-free photocatalyst (CNF/g-C₃N₄). CNF/g-C₃N₄ was then used to [...] Read more.

Herein, carbon nanofiber (CNF) was prepared by pyrolyzing electrospun cellulose nanofiber, which was further used to incorporate with graphitic carbon nitride (g-C₃N₄) to prepare metal-free photocatalyst (CNF/g-C₃N₄). CNF/g-C₃N₄ was then used to degrade bisphenol A (BPA) under visible light with the assistance of peroxymonosulfate (PMS). It was illustrated from the results that CNF with conjugated aromatic structure could significantly enhance the light absorption range and capability. At the existence of PMS, 0.5 g/L of CNF/g-C₃N₄ could efficiently degrade 0.05 mM of BPA within 45 min with a high total organic carbon removal rate of >70% under visible light. It was found that the reaction system could generate various reactive oxygen species (ROSs) including hydroxyl radical, superoxide radical and singlet oxygen for BPA degradation. Due to the existence of these species, the reaction system exhibited high performance adaptability towards abundant water matrices and high stability under consecutive runs. This work prospects a new strategy to develop a high-performance advanced oxidation system for quick organic pollutant degradation and mineralization. Full article

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

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14 pages, 7852 KB

Open AccessFeature PaperArticle

Silicalite-1 Zeolite-Supported Cu Nanoparticles for Ethanol Dehydrogenation: Influence of Silanols

by Chaofan He, Chao Tian, Yinghong Yue, Gangfeng Tang, Weiming Hua and Zi Gao

Catalysts 2025, 15(8), 787; https://doi.org/10.3390/catal15080787 - 18 Aug 2025

Viewed by 635

Abstract

The selective dehydrogenation of ethanol to acetaldehyde is an efficient alternative to biomass valorization. Herein, a series of Cu catalysts supported on Silicalite-1 zeolites with tunable contents of surface silanols and the same Cu loading of 3 wt% were synthesized by an impregnation [...] Read more.

The selective dehydrogenation of ethanol to acetaldehyde is an efficient alternative to biomass valorization. Herein, a series of Cu catalysts supported on Silicalite-1 zeolites with tunable contents of surface silanols and the same Cu loading of 3 wt% were synthesized by an impregnation method. The parent Silicalite-1 supports and as-synthesized Cu/S-1 catalysts were characterized by N₂ adsorption, XRD, SEM, TEM, TGA, DRIFT, ²⁹Si MAS NMR, XPS, and TPR. The Cu dispersion and Cu species distribution of Cu/S-1 catalysts can be modulated by engineering the amount of silanol groups on the support. More silanols present on the surfaces of parent Silicalite-1 supports can promote the Cu dispersion, and lead to a higher Cu⁺/Cu⁰ molar ratio arising from strong interfacial interaction between Cu species and silanols on the Silicalite-1 support via the formation of Si-O-Cu bonds. Thus, higher catalytic activity is achieved. Full article

(This article belongs to the Special Issue Back to the Future: Advances in Porous and Nanoscale Catalysts for Biomass Conversion to Value-Added Products)

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16 pages, 2126 KB

Open AccessArticle

Characteristic Influence of Cerium Ratio on PrMn Perovskite-Based Cathodes for Solid Oxide Fuel Cells

by Esra Balkanlı Ünlü, Meltem Karaismailoğlu Elibol and Halit Eren Figen

Catalysts 2025, 15(8), 786; https://doi.org/10.3390/catal15080786 - 18 Aug 2025

Viewed by 566

Abstract

In this study, cerium with different ratios (x = 0 (zero), 0.1, 0.15, 0.5) was added to the PrMn structure as an A-site material to evaluate characteristic behavior as a potential cathode material for solid oxide fuel cells. The Pr_xCe_1−x [...] Read more.

In this study, cerium with different ratios (x = 0 (zero), 0.1, 0.15, 0.5) was added to the PrMn structure as an A-site material to evaluate characteristic behavior as a potential cathode material for solid oxide fuel cells. The Pr_xCe_1−xMnO_3−δ electrocatalysts were synthesized using the sol–gel combustion method and were assessed for their electrochemical, phase, and structural properties, as well as desorption and reducibility capabilities. Phase changes, from orthorhombic to cubic structures observed upon cerium additions, were evaluated via the X-Ray diffraction method. X-Ray photoelectron spectroscopy (XPS) showed the valence states of the surface between the Ce⁴⁺/Ce³⁺ and Pr⁴⁺/Pr³⁺ redox pairs, while oxygen temperature programmed desorption (O₂-TPD) analysis was used to evaluate the oxygen adsorption and desorption behavior of the electrocatalysts. Redox characterization, evaluated via hydrogen atmosphere temperature-programmed reduction (H₂-TPR), revealed that a higher cerium ratio in the structure lowered the reduction temperature, suggesting a better dynamic oxygen exchange capability at a lower temperature for the Pr_0.5Ce_0.5MnO_3−δ catalyst compared to the electrochemical behavior analysis by the electrochemical impedance spectroscopy method. Moreover, the symmetrical cell tests with Pr_0.5Ce_0.5MnO_3−δ electrodes showed that, when combined with scandia-stabilized zirconia (ScSZ) electrolyte, the overall polarization resistance was reduced by approximately 28% at 800 °C compared to cells with yttria-stabilized zirconia (YSZ) electrolyte. Full article

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15 pages, 4908 KB

Open AccessFeature PaperArticle

Boosting the Bifunctional Catalytic Activity of La_0.85Y_0.15Ni_0.7Fe_0.3O₃ Perovskite Air Electrode with Facile Hybrid Strategy of Metallic Oxide for Rechargeable Zn–Air Batteries

by Xiankai Yi, Guangwei Zhuang, Junhua Bai, Jiaxing Yan and Yifeng Zheng

Catalysts 2025, 15(8), 785; https://doi.org/10.3390/catal15080785 - 17 Aug 2025

Viewed by 635

Abstract

Developing cost-effective, sustainable, and high-performance air electrode catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a significant challenge in the advancement of rechargeable zinc–air batteries (ZABs). Herein, we successfully construct a vacancy-rich heterogeneous perovskite La_0.85Y_0.15 [...] Read more.

Developing cost-effective, sustainable, and high-performance air electrode catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a significant challenge in the advancement of rechargeable zinc–air batteries (ZABs). Herein, we successfully construct a vacancy-rich heterogeneous perovskite La_0.85Y_0.15Ni_0.7Fe_0.3O₃ (LYNF) hybridized with Co₃O₄ spinel nanoparticles using a simple chemical bath-assisted method. The Co₃O₄ composite LYNF material is systematically evaluated as the bifunctional catalyst for ZABs in the proportion of 25 wt%, 50w t%, and 75 wt% (denoted as LYNF-xCo₃O₄, x = 0.25, 0.5, 0.75). The results confirm an intimate coupling between the perovskite and spinel phases, along with a significant increase in oxygen vacancy concentration. Among the composites, LYNF-0.5Co₃O₄ exhibits the best performance, achieving an ORR onset potential of 0.813 V vs. RHE at −0.1 mA cm⁻² and a lower OER overpotential of 441 mV at 10 mA cm⁻². When applied as the air electrode catalyst in ZABs, LYNF-0.5Co₃O₄ displays the highest discharge voltage and a peak power density of 115 mW cm⁻², representing a 20% improvement over pristine LYNF. The enhanced performance of the LYNF-0.5Co₃O₄ composite is attributed to the accumulation of Co₃O₄ nanoparticles within the LYNF matrix, which introduces numerous electrochemically active sites and facilitates the charge and mass transport during the catalytic process in ZABs. Full article

(This article belongs to the Special Issue Metal Oxide-Supported Catalysts)

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21 pages, 1307 KB

Open AccessReview

Synergistic Catalysis for Algae Control: Integrating Sonocavitation and Chemical Catalysis

by Yunxi Zhang, Xiaoge Wu and Muthupandian Ashokkumar

Catalysts 2025, 15(8), 784; https://doi.org/10.3390/catal15080784 - 17 Aug 2025

Viewed by 734

Abstract

This review systematically summarizes recent advances in ultrasound–chemical catalytic synergistic technology for controlling harmful algae blooms, focusing on the multi-mechanism cooperation of catalysts, oxidants, and nanomaterials within sonocavitation systems. The technology enhances coupling efficiency between cavitation effects and radical oxidation while leveraging interfacial [...] Read more.

This review systematically summarizes recent advances in ultrasound–chemical catalytic synergistic technology for controlling harmful algae blooms, focusing on the multi-mechanism cooperation of catalysts, oxidants, and nanomaterials within sonocavitation systems. The technology enhances coupling efficiency between cavitation effects and radical oxidation while leveraging interfacial regulation capabilities of catalysts (e.g., charge adsorption, carrier migration) to selectively disrupt algae cell structures and efficiently degrade extracellular organic matter. Three key innovations are highlighted: (1) development of a multi-mechanism synergistic system that overcomes traditional technical limitations through moderate pre-oxidation strategies for precise algae control; (2) first systematic elucidation of the bridging role of sonoporation in ultrasound–chemical synergy; (3) decipherment of interface-targeted regulation mechanisms that enhance oxidation efficiency. Collectively, these advances establish an engineerable new paradigm characterized by high efficiency, operational stability, and minimized ecological risks. Full article

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18 pages, 5597 KB

Open AccessFeature PaperArticle

Loading Eu₂O₃ Enhances the CO Oxidation Activity and SO₂ Resistance of the Pt/TiO₂ Catalyst

by Zehui Yu, Jianyu Cai, Yudong Meng, Jian Li, Wenjun Liang and Xing Fan

Catalysts 2025, 15(8), 783; https://doi.org/10.3390/catal15080783 - 16 Aug 2025

Viewed by 629

Abstract

Pt/TiO₂ and Pt-Eu₂O₃/TiO₂ catalysts were prepared via the impregnation method for catalytic oxidation of CO. The Pt-2Eu₂O₃/TiO₂ catalyst exhibited better CO oxidation activity as well as greater SO₂ resistance than the [...] Read more.

Pt/TiO₂ and Pt-Eu₂O₃/TiO₂ catalysts were prepared via the impregnation method for catalytic oxidation of CO. The Pt-2Eu₂O₃/TiO₂ catalyst exhibited better CO oxidation activity as well as greater SO₂ resistance than the Pt/TiO₂ catalyst. For the inlet gas consisting of 0.8% CO, 5% O₂, and balanced N₂, the lowest complete conversion temperatures (T₁₀₀) of CO were 120 °C and 140 °C for the Pt-2Eu₂O₃/TiO₂ and Pt/TiO₂ catalysts, respectively. During the 72 h SO₂-resistance test at 200 °C under an inlet gas composition of 0.8% CO, 5% O₂, 15% H₂O, 50 ppm SO₂, and balanced N₂, the CO conversion on the Pt-2Eu₂O₃/TiO₂ catalyst remained >99%, while that on the Pt/TiO₂ catalyst gradually decreased to 77.8%. Pre-loading 2 wt% Eu₂O₃ on TiO₂ enhanced the dispersion of Pt, increased the proportion of Pt⁰, and facilitated the adsorption and dissociation of H₂O, all of which promoted CO oxidation. SO₂ preferentially occupied the Eu₂O₃ sites by forming stable sulfates on the Pt-2Eu₂O₃/TiO₂ catalyst, which protected the Pt active sites from poisoning. The OH* species produced from the dissociation of H₂O played a significant role in promoting CO oxidation through the formation of COOH* as the key reaction intermediate. The developed Pt-2Eu₂O₃/TiO₂ catalyst has great application potential in terms of the removal of CO from industrial flue gases. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis in Air Pollution Control)

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31 pages, 4081 KB

Open AccessFeature PaperReview

Sulfur Vacancy Engineering in Photocatalysts for CO₂ Reduction: Mechanistic Insights and Material Design

by Bingqing Chang, Xin Liu, Xianghai Song, Yangyang Yang, Jisheng Zhang, Weiqiang Zhou and Pengwei Huo

Catalysts 2025, 15(8), 782; https://doi.org/10.3390/catal15080782 - 16 Aug 2025

Viewed by 797

Abstract

Against the backdrop of increasing global warming, exploring sustainable pathways to mitigate the greenhouse effect has become a central issue for the ecological and energy future. Photocatalytic reduction of CO₂ technology shows a broad application prospect due to its ability to directly [...] Read more.

Against the backdrop of increasing global warming, exploring sustainable pathways to mitigate the greenhouse effect has become a central issue for the ecological and energy future. Photocatalytic reduction of CO₂ technology shows a broad application prospect due to its ability to directly convert CO₂ into high-value-added hydrocarbon fuels and to use solar energy, a clean energy source, to drive the reaction. However, traditional semiconductor catalysts generally suffer from insufficient activity and poor product selectivity in the actual reaction, which cannot meet the requirements of practical applications. In recent years, sulfur vacancy, as an effective material modulation strategy, has demonstrated a remarkable role in enhancing photocatalytic performance. This paper reviews a series of research reports on sulfur vacancies in recent years, introduces the methods of preparing sulfur vacancies, and summarizes the commonly used characterization methods of sulfur vacancies. Finally, the mechanism of introducing sulfur vacancies to promote CO₂ reduction is discussed, which improves the photocatalytic activity and selectivity by enhancing light absorption, facilitating carrier separation, improving CO₂ adsorption and activation, and promoting the stability of reaction intermediates. This review aims to provide theoretical support for an in-depth understanding of the role of sulfur vacancies in photocatalytic systems and to provide a view on the future direction and potential challenges of sulfur vacancies. Full article

(This article belongs to the Special Issue Catalytic Carbon Emission Reduction and Conversion in the Environment)

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19 pages, 3683 KB

Open AccessArticle

Electrophoretic Deposition of Gold Nanoparticles on Highly Ordered Titanium Dioxide Nanotubes for Photocatalytic Application

by Halima Benghanoum, Lotfi Khezami, Rabia Benabderrahmane Zaghouani, Syrine Sassi, Ahlem Guesmi, Amal Bouich, Bernabé Mari Soucase and Anouar Hajjaji

Catalysts 2025, 15(8), 781; https://doi.org/10.3390/catal15080781 - 16 Aug 2025

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Abstract

This work focused on the photocatalytic performance enhancement of titanium dioxide (TiO₂) nanotubes decorated by gold nanoparticles. The surface of the nanotubes synthesized using the anodization technique was modified with subsequent deposition of gold nanoparticles (Au-NPs) via electrophoretic deposition. The impact [...] Read more.

This work focused on the photocatalytic performance enhancement of titanium dioxide (TiO₂) nanotubes decorated by gold nanoparticles. The surface of the nanotubes synthesized using the anodization technique was modified with subsequent deposition of gold nanoparticles (Au-NPs) via electrophoretic deposition. The impact of electrophoretically deposited gold nanoparticles (Au-NPs) on TiO₂ nanotubes, with varying deposition times (5 min, 8 min and 12 min), was investigated in the degradation of amido black (AB) dye. The morphological analysis using scanning electron microscopy (SEM, TESCAN VEGA3, TESCAN Orsay Holding, Brno, Czech Republic) and transmission electron microscopy (TEM, JEM—100CX2, JEOL Japan). revealed a well-organized nanotubular structure of TiO₂, with a wall thickness of 25 nm and an internal diameter of 75 nm. Optical study, including photoluminescence and diffuse reflectance spectroscopy, provided evidence of charge transfer between the Au-NPs and the TiO₂-NTs. Furthermore, the photocatalytic measurements showed that the enhanced photocatalytic activity of the TiO₂-NTs resulted from successful Au deposition onto their surface, surpassing that of the pure sample. This improvement is attributed to the higher work function of gold nanoparticles, which effectively promoted the separation of photogenerated electron–hole pairs. The sample Au-NPs/TiO₂-NTs with a deposition time of 5 min exhibited the best photocatalytic efficiency, achieving an 85% degradation rate after 270 min under UV irradiation. Moreover, the enhancement obtained was also attributed to the plasmonic effect induced by Au-NPs. Kinetic investigations revealed that the photocatalytic reaction followed apparent first-order kinetics, highlighting the efficiency of Au-NPs/TiO₂-NTs as a photocatalyst for dye degradation. Full article

(This article belongs to the Special Issue Photocatalysis towards a Sustainable Future)

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23 pages, 6240 KB

Open AccessFeature PaperReview

Piancatelli–Margarita Oxidation and Its Recent Applications in Organic Synthesis

by Marco Bella

Catalysts 2025, 15(8), 780; https://doi.org/10.3390/catal15080780 - 15 Aug 2025

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Abstract

Piancatelli–Margarita oxidation is a reaction where primary and secondary alcohols are converted to aldehydes and ketones, respectively. It utilizes TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl), a stable aminoxy radical, as the catalyst and BAIB (bis(acetoxy)iodobenzene), a hypervalent iodine compound, as the stoichiometric oxidant. The reaction proceeds [...] Read more.

Piancatelli–Margarita oxidation is a reaction where primary and secondary alcohols are converted to aldehydes and ketones, respectively. It utilizes TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl), a stable aminoxy radical, as the catalyst and BAIB (bis(acetoxy)iodobenzene), a hypervalent iodine compound, as the stoichiometric oxidant. The reaction proceeds at room temperature, without the need for strong acids, bases, or anhydrous conditions. Mild reaction conditions allow for the chemoselective oxidation of complex and sensitive substrates and the selective oxidation of primary alcohols in the presence of secondary alcohols. The reaction conditions can be controlled to favor the oxidation of primary alcohols to aldehydes or promote the overoxidation of aldehydes to carboxylic acids. This review highlights some recent applications (2020–2025), especially in total synthesis, with special emphasis on large-scale reactions. This review aims to honor the memory of Prof. Piancatelli (1936–2025) and Dr. Roberto Margarita (1970–2016), who developed this reaction. Full article

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

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29 pages, 1441 KB

Open AccessReview

Titanocene Complexes Applied in Organic Transformations

by Mingming Yang, Deying Leng, Zhenhua Wang, Xiu Wang and Ziwei Gao

Catalysts 2025, 15(8), 779; https://doi.org/10.3390/catal15080779 - 15 Aug 2025

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Abstract

Titanium, the second most abundant and one of the cheapest, non-toxic transition metals in the Earth’s crust, is highly favorable for catalytic applications due to its widespread availability, low cost, low toxicity, and well-documented biocompatibility. However, because of its high affinity for oxygen [...] Read more.

Titanium, the second most abundant and one of the cheapest, non-toxic transition metals in the Earth’s crust, is highly favorable for catalytic applications due to its widespread availability, low cost, low toxicity, and well-documented biocompatibility. However, because of its high affinity for oxygen and inherent Lewis acidity, titanium complexes generally exhibit lower tolerance toward various functional groups compared with complexes of later transition metals. The incorporation of cyclopentadienyl ligands significantly enhances the structural tunability of these complexes in their 3D configuration. By modifying the ligand framework, it is possible to fine-tune the Lewis acidity of the central titanium atom as well as the lability and binding characteristics of the ligands. This strategy enables precise control over the catalytic performance of titanocene complexes. The main body of this review provides an overview of recent advances in titanocene catalysis within the field of chemical synthesis since 2019. It includes illustrative examples that demonstrate the substrate scope and practical applications of titanocene catalysts in the synthesis of complex organic molecules and natural products. Finally, the review outlines current research opportunities and strategic directions for future developments in titanocene-based catalysis. Full article

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

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16 pages, 1706 KB

Open AccessFeature PaperArticle

An Improved Flow-Through Photodegradation Device for the Removal of Emerging Contaminants

by Ron Schweitzer, Soliman Khatib, Lior Levy and Giora Rytwo

Catalysts 2025, 15(8), 778; https://doi.org/10.3390/catal15080778 - 15 Aug 2025

Viewed by 620

Abstract

Cost-effective procedures usually cannot achieve complete removal of priority contaminants present in water at very low concentrations (as pesticides or pharmaceuticals). Advanced oxidation processes (AOPs) represent promising technologies for removing priority contaminants from water at trace concentrations, yet practical implementation remains limited due [...] Read more.

Cost-effective procedures usually cannot achieve complete removal of priority contaminants present in water at very low concentrations (as pesticides or pharmaceuticals). Advanced oxidation processes (AOPs) represent promising technologies for removing priority contaminants from water at trace concentrations, yet practical implementation remains limited due to technical and economic constraints. This study presents an innovative flow-through photodegradation device designed to overcome current limitations while achieving efficient contaminant removal at industrial scale. The device integrates a UVC 254 nm lamp-equipped flow chamber with automated dosing pumps for hydrogen peroxide and/or solid catalyst suspensions, coupled with a 30 nm porous membrane filtration system for catalyst recirculation. This configuration optimizes light–catalyst–pollutant contact while enabling combined catalytic processes. Performance evaluation using acesulfame (ACE) and iohexol (IHX) as model contaminants demonstrated rapid and effective removal. IHX degradation with UVC and 75 μM H₂O₂ achieved complete removal with t₉₅% = 7.23 ± 1.21 min (pseudo-order 0.25, t₁/₂ = 3.27 ± 0.39 min), while ACE photolysis (with UVC only) required t₉₅% = 14.88 ± 2.02 min (pseudo-order 1.27, t₁/₂ = 2.35 ± 0.84 min). The introduction of t₉₅% as a performance metric provides practical insights for near-complete contaminant removal requirements. Real-world efficacy was confirmed using tertiary wastewater treatment plant effluents containing 14 μg/L IHX, achieving complete removal within 8 min. However, carbamazepine degradation proved slower (t₉₅% > 74 h), highlighting the need for combined catalytic approaches for recalcitrant compounds. Spiking experiments (1000 μg/L) revealed concentration-dependent kinetics and synergistic effects between co-present contaminants. Analysis identified degradation byproducts consistent with previous studies, including tri-deiodinated iohexol (474.17 Da) intermediates. This scalable system, constructed from commercially available components, demonstrates potential for cost-effective industrial implementation. The modular design allows adaptation to various contaminants through adjustable AOP combinations (UV/H₂O₂, photocatalysts, ozone), representing a practical advancement toward addressing the gap between laboratory-scale photocatalytic research and full-scale water treatment applications. Full article

(This article belongs to the Special Issue Advances in Photocatalytic Degradation)

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10 pages, 4385 KB

Open AccessArticle

Interfacial Electron Transfer in Strategically Engineered Pt₃Rh/C Ultrafine Alloy Nanoparticle Catalysts Facilitates Exceptional Performance in Li-O₂ Batteries

by Xing Xu, Yinkun Gao and Xudong Li

Catalysts 2025, 15(8), 777; https://doi.org/10.3390/catal15080777 - 15 Aug 2025

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Abstract

A major challenge for Li-O₂ batteries is the slow kinetics of oxygen reduction (ORR) and evolution (OER) reactions. This work presents a high-performance Pt₃Rh/C composite cathode where Pt-Rh nanoalloys are uniformly dispersed on 3D nanoporous carbon. The bimetallic architecture demonstrates [...] Read more.

A major challenge for Li-O₂ batteries is the slow kinetics of oxygen reduction (ORR) and evolution (OER) reactions. This work presents a high-performance Pt₃Rh/C composite cathode where Pt-Rh nanoalloys are uniformly dispersed on 3D nanoporous carbon. The bimetallic architecture demonstrates significantly enhanced ORR/OER activity compared to conventional catalysts. Super P, with a large specific surface area and omnipresent pores with diverse size distribution, provided sufficient storage space for Li₂O₂ and facilitated transport channels for Li⁺ and O₂, while the highly conductive Pt₃Rh NPs optimized catalytic efficiency. XPS reveals a prominent electron transfer process between Pt and Rh; the Rh sites in Pt₃Rh/C alloy can effectively act as electron donors to improve the oxygen/lithium peroxide (O₂/Li₂O₂) redox chemistry in LOB. Therefore, the Pt₃Rh/C electrode shows the minimum overpotential (0.60 V) for efficient oxygen reduction and evolution under an upper-limit capacity of 2000 mAh g⁻¹. This work introduces a Pt₃Rh/C nanoalloy synthesis method that boosts Li-O₂ battery efficiency by accelerating oxygen reaction kinetics. Full article

(This article belongs to the Section Electrocatalysis)

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14 pages, 2664 KB

Open AccessFeature PaperArticle

Synergistic Effects of UV Radiation and H₂O₂ on Chloramphenicol Degradation by REE-Based Catalysts

by Alice Cardito, Mariateresa Lettieri, Lorenzo Saviano, Olga Sacco, Giusy Lofrano, Vincenzo Vaiano, Giovanni Libralato, Marco Guida and Maurizio Carotenuto

Catalysts 2025, 15(8), 776; https://doi.org/10.3390/catal15080776 - 14 Aug 2025

Viewed by 497

Abstract

The persistent occurrence of antibiotics like chloramphenicol (CAP) in aquatic systems poses serious environmental and public health risks. This study investigates the photocatalytic degradation of CAP using cerium oxide (CeO₂), lanthanum oxide (La₂O₃), and lanthanum-doped cerium oxide [...] Read more.

The persistent occurrence of antibiotics like chloramphenicol (CAP) in aquatic systems poses serious environmental and public health risks. This study investigates the photocatalytic degradation of CAP using cerium oxide (CeO₂), lanthanum oxide (La₂O₃), and lanthanum-doped cerium oxide (Ce_xLa_yO₂₋_δ), synthesized via co-precipitation. The catalysts were tested under a solar simulator, UV-A, and UV-C radiation, both with and without hydrogen peroxide (H₂O₂). Structural characterization confirmed successful synthesis of nanometric catalysts, with La doping causing lattice expansion in CeO₂ and a reduction in crystallite size (from 27 nm in CeO₂ to ~20 nm in doped samples). Photolysis alone achieved limited CAP removal (~34–35%), while photocatalysis with La₂O₃ under UV-A and UV-C improved removal up to 58% and 55%, respectively. Complete degradation was obtained with La₂O₃ under UV-C in the presence of H₂O₂ within 15 min. Pareto analysis highlighted the dominant effect of the interaction between radiation and H₂O₂ (43%), while the catalyst type contributed minimally (0.23%). These findings confirm the potential of REE oxides, especially La₂O₃, in advanced oxidation processes and underscore the importance of light source and radical generation over catalyst selection alone. Full article

(This article belongs to the Special Issue Innovative Catalytic and Photocatalytic Systems for Environmental Remediation, 2nd Edition)

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31 pages, 8890 KB

Open AccessReview

Advancements in Non-Precious Metal Catalysts for High-Temperature Proton-Exchange Membrane Fuel Cells: A Comprehensive Review

by Naresh Narayanan, Balamurali Ravichandran, Indubala Emayavaramban, Huiyuan Liu and Huaneng Su

Catalysts 2025, 15(8), 775; https://doi.org/10.3390/catal15080775 - 14 Aug 2025

Viewed by 883

Abstract

High-Temperature Proton-Exchange Membrane Fuel Cells (HT-PEMFCs) represent a promising clean energy technology and are valued for their fuel flexibility and simplified balance of plant. Their commercialization, however, is critically hindered by the prohibitive cost and resource scarcity of platinum-group metal (PGM) catalysts. The [...] Read more.

High-Temperature Proton-Exchange Membrane Fuel Cells (HT-PEMFCs) represent a promising clean energy technology and are valued for their fuel flexibility and simplified balance of plant. Their commercialization, however, is critically hindered by the prohibitive cost and resource scarcity of platinum-group metal (PGM) catalysts. The challenge is amplified in the phosphoric acid (PA) electrolyte of HT-PEMFCs, where the severe anion poisoning of PGM active sites necessitates impractically high catalyst loadings. This review addresses the urgent need for cost-effective alternatives by providing a comprehensive assessment of recent advancements in non-precious metal (NPM) catalysts for the oxygen reduction reaction (ORR) in HT-PEMFCs. It systematically explores synthesis strategies and structure–performance relationships for emerging catalyst classes, including transition metal compounds, metal–nitrogen–carbon (M-N-C) materials, and metal-free heteroatom-doped carbons. A significant focus is placed on M-N-C catalysts, particularly those with atomically dispersed Fe-Nx active sites, which have emerged as the most viable replacements for platinum due to their high intrinsic activity and notable tolerance to phosphate poisoning. This review critically analyzes key challenges that impede practical application, such as the trade-off between catalyst activity and stability, mass transport limitations in thick electrodes, and long-term degradation in the harsh PA environment. Finally, it outlines future research directions, emphasizing the need for a synergistic approach that integrates computational modeling with advanced operando characterization to guide the rational design of durable, high-performance catalysts and electrode architectures, thereby accelerating the path to commercial viability for HT-PEMFC technology. Full article

(This article belongs to the Section Electrocatalysis)

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22 pages, 11315 KB

Open AccessArticle

Improvement of Cleaner Composting Production by Manganese Dioxide Nanozyme with Streptomyces rochei ZY-2: From the Humus Formation to Greenhouse Gas Emissions

by Guoxiang Liu, Lili Lin, Jing Zhang, Enhui Sun, Cheng Yong, Ling Chen, Hongying Huang, Hongmei Jin and Ping Qu

Catalysts 2025, 15(8), 774; https://doi.org/10.3390/catal15080774 - 14 Aug 2025

Viewed by 534

Abstract

This study innovatively integrates ball-milled manganese dioxide nanozyme (MDMP) with the Streptomyces rochei ZY-2 inoculant in aerobic rice straw composting. The ZY-2 inoculant efficiently degrades the three major components to generate humus precursors such as phenols and quinones, while the MnO₂ nanozyme [...] Read more.

This study innovatively integrates ball-milled manganese dioxide nanozyme (MDMP) with the Streptomyces rochei ZY-2 inoculant in aerobic rice straw composting. The ZY-2 inoculant efficiently degrades the three major components to generate humus precursors such as phenols and quinones, while the MnO₂ nanozyme accelerates precursor polymerization into stable humic acid (HA) via oxygen vacancy-mediated catalytic activity. Simultaneously, this combination regulates microbial communities to reduce greenhouse gas emissions. The results show that the co-treatment group (ZY-2+ MnO₂ nanozyme) had an increased HA content by 30.8%, raised HA/FA ratio by 31.6%, and degradation rates of 30.75%, 31.39%, and 16.74% for cellulose, hemicellulose, and lignin, respectively. Additionally, cumulative emissions of CH₄, N₂O, and NH₃ were significantly reduced by 35.22%, 28.23%, and 25.67% compared to the control, attributed to the MnO₂ nanozyme’s inhibition of methanogens, enhanced nitrogen fixation, and ZY-2-driven microbial metabolic optimization. This study proposes a dual-effect strategy of “enhanced humification-synergistic greenhouse gas mitigation” for agricultural waste recycling, demonstrating significant practical value. Full article

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4 pages, 163 KB

Open AccessEditorial

Sustainable Catalysis for Green Chemistry and Energy Transition

by Muhammad Saeed Akhtar and Wajid Zaman

Catalysts 2025, 15(8), 773; https://doi.org/10.3390/catal15080773 - 14 Aug 2025

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Abstract

Catalysis sits at the heart of sustainable development, and plays an instrumental role in addressing modern environmental challenges [...] Full article

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

19 pages, 4405 KB

Open AccessArticle

Photodegradation of Pyridine in a Fluidized Bed Photocatalytic Reactor Using Pt-ZnO Supported on Al₂O₃ as a Catalyst

by Ruby Gines, Carlos Montalvo, Guadalupe Luna, Daniel Montalvo, Rosa M. Cerón, Julia G. Cerón, Sinuhe Ginés, Aracely García and Claudia A. Aguilar

Catalysts 2025, 15(8), 772; https://doi.org/10.3390/catal15080772 - 13 Aug 2025

Viewed by 616

Abstract

Pyridine is a recalcitrant organic compound present in industrial wastewater that causes severe effects on the environment and the health of living beings, as it is considered a toxic, mutagenic, teratogenic, and carcinogenic agent. Therefore, this research explored the efficacy of a zinc [...] Read more.

Pyridine is a recalcitrant organic compound present in industrial wastewater that causes severe effects on the environment and the health of living beings, as it is considered a toxic, mutagenic, teratogenic, and carcinogenic agent. Therefore, this research explored the efficacy of a zinc oxide catalyst, doped with platinum nanoparticles and supported alumina through the precipitation method, for the photocatalytic degradation of pyridine using a fluidized bed reactor. A Box–Behnken experimental design was used to analyze the effect of the pH (4–10), the pyridine concentration (20–300 ppm), and the amount of catalyst (20–100 g). The X-ray diffraction (XRD) characterization results confirmed the hexagonal structure of the zinc oxide and the successful incorporation of platinum. Scanning electron microscopy (SEM) revealed a nano-bar morphology upon catalyst doping, favoring the photocatalytic activity. Pyridine removal of 57.7% was achieved under the following conditions: a pH of 4, 160 ppm of pyridine, and 100 g of catalyst. The process followed a pseudo-first-order model, obtaining the reaction constant k₁ = 1.943 × 10⁻³ min⁻¹ and the adsorption constant k₂ = 1.527 × 10⁻³ L/mg. The results showed high efficiency and stability of the catalyst in the fluidized bed reactor for pyridine degradation, especially under acidic conditions, representing a promising technological alternative for treating industrial wastewater contaminated with N-heterocycles such as pyridine. Full article

(This article belongs to the Special Issue Advances in Photocatalytic Degradation)

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14 pages, 3138 KB

Open AccessFeature PaperArticle

Construction of BiOBr/BNQDs Heterostructure Photocatalyst and Performance Studies of Photocatalytic Degradation of RhB

by Yufeng Qin, Xinyu Peng, Tong Wu, Yi Zhong, Hong Xu, Zhiping Mao and Linping Zhang

Catalysts 2025, 15(8), 771; https://doi.org/10.3390/catal15080771 - 13 Aug 2025

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Abstract

As a common semiconductor material, BiOBr has a unique layered structure and a suitable bandgap. However, the slow electron–hole separation efficiency leads to poor photocatalytic performance. To solve this problem, BiOBr/BNQDs heterojunctions were constructed. BiOBr/BNQDs composite photocatalysts were prepared by the solvothermal method, [...] Read more.

As a common semiconductor material, BiOBr has a unique layered structure and a suitable bandgap. However, the slow electron–hole separation efficiency leads to poor photocatalytic performance. To solve this problem, BiOBr/BNQDs heterojunctions were constructed. BiOBr/BNQDs composite photocatalysts were prepared by the solvothermal method, and the cocatalyst BNQDs were loaded onto BiOBr via electrostatic adsorption to enhance the photocatalytic degradation activity towards Rhodamine B (RhB). The photocatalysts were characterized by FT-IR, XRD, XPS, SEM-EDS, UV-Vis, PL, EIS, etc. Compared with pure BiOBr, the construction of heterojunctions BiOBr/BNQDs realized the rapid elimination of weak carriers and the effective separation and enrichment of high-energy carriers, which improved the efficiency of photocatalytic degradation of RhB. Among them, BiOBr/BNQDs-8.3% demonstrated the highest photocatalytic activity. The degradation rate of RhB under visible light irradiation for 60 min was up to 98.56%, and the reaction rate constant was 0.0696 min⁻¹, which was 2.80 times that of pure BiOBr. Moreover, after five photocatalytic cycles, the degradation rate was still 87.58%, demonstrating good cycling stability. Full article

(This article belongs to the Special Issue Advances in Photocatalytic Degradation of Pollutants in Wastewater)

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13 pages, 5037 KB

Open AccessFeature PaperArticle

First-Principles Study of Sn-Doped RuO₂ as Efficient Electrocatalysts for Enhanced Oxygen Evolution

by Caiyan Zheng, Qian Gao and Zhenpeng Hu

Catalysts 2025, 15(8), 770; https://doi.org/10.3390/catal15080770 - 13 Aug 2025

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Abstract

Improving the catalytic performance of the oxygen evolution reaction (OER) for water splitting in acidic media is crucial for the production of clean and renewable hydrogen energy. Herein, we study the OER electrocatalytic properties of various active sites on four exposed (110) and [...] Read more.

Improving the catalytic performance of the oxygen evolution reaction (OER) for water splitting in acidic media is crucial for the production of clean and renewable hydrogen energy. Herein, we study the OER electrocatalytic properties of various active sites on four exposed (110) and (

\bar{1}

10) surfaces of Sn-doped RuO₂ (Sn/RuO₂) with antiferromagnetic arrangements in acidic environments. The Sn/RuO₂ bulk structure with the Cm space group exhibits favorable thermodynamic stability. The coordinatively unsaturated metal (M_cus) sites distributed on the right branch of the volcano plot are generally more active than the bridge-bonded lattice oxygen (O_br) sites located on the left. Different from the conventional knowledge that the most active site is located in the nearest neighbor of the doped atom, it has a lower OER overpotential when the active site is 3.6 Å away from the doped Sn atom. Among the sites studied, the 46-Ru_cus site exhibits the optimal OER catalytic performance. The inherent factors affecting the OER activity of each site on the Sn/RuO₂ surface are further analyzed, including the center of the d/p band at the active sites, the average electrostatic potential of the ions, and the number of transferred electrons. This work provides a reminder for the selection of active sites used to evaluate catalytic performance, which will benefit the development of efficient OER electrocatalysts. Full article

(This article belongs to the Topic Water Splitting and CO₂ Reduction via Electrocatalysis and Photocatalysis)

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13 pages, 6309 KB

Open AccessArticle

Reusable Three-Dimensional TiO₂@MoS₂ Core–Shell Photoreduction Material: Designed for High-Performance Seawater Uranium Extraction

by Chen Xie, Tianyi Zhao, Feng Zhou and Bohao Zhao

Catalysts 2025, 15(8), 769; https://doi.org/10.3390/catal15080769 - 13 Aug 2025

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Abstract

Photocatalysis offers a cost-effective and eco-friendly approach for environmental remediation, yet traditional powdered photocatalysts suffer from poor recyclability and separation challenges. To address these limitations, we developed a recyclable carbon fiber-supported composite photocatalyst (CC/TiO₂ NRs@MoS₂ NPs) featuring a three-dimensional hierarchical core–shell [...] Read more.

Photocatalysis offers a cost-effective and eco-friendly approach for environmental remediation, yet traditional powdered photocatalysts suffer from poor recyclability and separation challenges. To address these limitations, we developed a recyclable carbon fiber-supported composite photocatalyst (CC/TiO₂ NRs@MoS₂ NPs) featuring a three-dimensional hierarchical core–shell architecture. This structure comprises a TiO₂ seed layer, vertically aligned TiO₂ nanorod arrays as the core, and a MoS₂ nanoparticle shell, fabricated via sequential deposition. Under simulated solar irradiation, the TiO₂@MoS₂ heterojunction exhibited significantly enhanced uranium adsorption capacity, achieving a remarkable 97.3% photocatalytic removal efficiency within 2 h. At an initial uranium concentration of 200 ppm, the material demonstrated an exceptional extraction capacity of 976.7 mg g⁻¹, outperforming most reported photocatalysts. These findings highlight the potential of this 3D core–shell design for efficient uranium recovery and environmental purification applications. Full article

(This article belongs to the Special Issue Synthesis and Catalytic Applications of Advanced Porous Materials)

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24 pages, 5693 KB

Open AccessFeature PaperArticle

Relationship Between Number and Strength of Acid–Base Catalytic Sites and Their Performances in Isopropanol Dehydration Reaction

by Georgeta Postole, Sandra Segondy, Tristan Cabanis, Tien-Hoang Nguyen, Aline Auroux and Jean-Luc Dubois

Catalysts 2025, 15(8), 768; https://doi.org/10.3390/catal15080768 - 12 Aug 2025

Viewed by 689

Abstract

Commercial alumina and silica–alumina catalysts were investigated for propylene (PEN) production via an isopropanol (IPA) dehydration reaction between 200 and 300 °C at an atmospheric pressure and IPA partial pressure of 5136 Pa. The reaction conditions were chosen to fit with the further [...] Read more.

Commercial alumina and silica–alumina catalysts were investigated for propylene (PEN) production via an isopropanol (IPA) dehydration reaction between 200 and 300 °C at an atmospheric pressure and IPA partial pressure of 5136 Pa. The reaction conditions were chosen to fit with the further conversion of PEN into value-added compounds with minimal capital cost, and the conceptual process design was discussed. The textural properties, structure and chemical composition of as-received and hydrothermally treated catalysts were characterised by the adsorption–desorption of N₂, X-ray fluorescence, X-ray diffraction and Nuclear Magnetic Resonance spectroscopy. The adsorption microcalorimetry of NH₃ and SO₂ was used to determine the amount, strength and strength distribution of acid–base sites, while the nature of the acid sites was investigated by Fourier Transform Infraed spectroscopy. Surface area, pore-size distribution and pore volume were not determining factors for the catalytic performances of studied solids in the conditions used here. The best-performing catalyst combined stable textural properties and a high number of high-strength acid sites (Q_diff > 150 kJ/mol NH₃) under hydrothermal conditions. The importance of determining the number and strength of acid sites of water-aged catalysts, when considering reactions where water is present as reactive or product, is underlined. Full article

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