Recent Advances in Biocatalytic Dearomative Spirocyclization Reactions
Activity and Stability Enhancement of Carbonic Anhydrase Entrapped Within Biomimetic Silica by Methyl-Substituted Silanes
Faster Microwave-Assisted Synthesis of Microspherical Carbons from Commercial and Biomass-Derived Carbohydrates
A Novel Polymer-Derived Ni/SiOC Catalyst for the Dry Reforming of Methane
Enhanced Oxygen Reduction Reaction Activity of Carbon-Supported Pt-Co Catalysts Prepared by Electroless Deposition and Galvanic Replacement

Journal Description

Catalysts

Catalysts is a peer-reviewed open access journal of catalysts and catalyzed reactions published monthly online by MDPI. The Romanian Catalysis Society (RCS) are partners of Catalysts journal and its members receive a discount on the article processing charge.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, Ei Compendex, CAPlus / SciFinder, CAB Abstracts, and other databases.
Journal Rank: JCR - Q2 (Chemistry, Physical) / CiteScore - Q1 (General Environmental Science )
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.6 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the first half of 2025).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Journal Cluster of Chemical Reactions and Catalysis: Catalysts, Chemistry, Electrochem, Inorganics, Molecules, Organics, Oxygen, Photochem, Reactions, Sustainable Chemistry.

Impact Factor: 4.0 (2024); 5-Year Impact Factor: 4.0 (2024)

Imprint Information Journal Flyer Open Access ISSN: 2073-4344

Latest Articles

26 pages, 6955 KB

Open AccessArticle

Recycling of Waste PET into Terephthalic Acid in Neutral Media Catalyzed by the Cracking Zeolite/Alumina Binder Acidic Catalyst

by Shaddad S. Alhamedi, Waheed Al-Masry, Ahmed S Al-Fatesh, Sajjad Haider, Asif Mahmood, Lahssen El Blidi and Abdulrahman Bin Jumah

Catalysts 2025, 15(11), 1072; https://doi.org/10.3390/catal15111072 (registering DOI) - 12 Nov 2025

Abstract

This study addresses the critical issue of environmental pollution from plastic waste by investigating an effective chemical recycling method for polyethylene terephthalate (PET) via neutral catalytic hydrolysis. We utilized a recoverable and regenerable composite catalyst based on cracking zeolite and γ-Al₂O₃, which possesses both Brønsted and Lewis acidic sites that facilitate the depolymerization of PET into its constituent monomers, terephthalic acid (TPA) and ethylene glycol (EG). This investigation reveals that the catalytic performance is strongly dependent on the total acid site concentration and the specific nature of these sites. A key finding is that a balanced acidic profile with a high proportion of Brønsted acid sites is crucial for enhancing PET hydrolysis attributed to a significant decrease in the activation energy of the reaction. The experiments were conducted in a stirred stainless-steel autoclave reactor, where key parameters such as temperature (210–230 °C), the PET-to-water ratio (1:2 to 1:5), and reaction time were systematically varied. Under optimal conditions of 210 °C and a 6 h reaction time, the process achieved near-complete PET depolymerization (99.5%) and a high TPA yield (90.24%). The catalyst demonstrated remarkable recyclability, maintained its activity over multiple cycles and was easily regenerated. Furthermore, the recovered TPA was of high quality, with a purity of 98.74% as confirmed by HPLC, and exhibited a melt crystallization temperature 14 °C lower than that of the commercial standard. These results not only demonstrate the efficiency and sustainability of neutral catalytic hydrolysis using zeolite/alumina composites but also provide valuable insights for designing advanced catalysts with tunable acidic properties. By demonstrating the importance of tuning acidic properties, specifically the balance between Brønsted and Lewis sites, this work lays a foundation for developing more effective catalysts that can advance circular economy goals for PET recycling. Full article

(This article belongs to the Topic Advanced Materials in Chemical Engineering)

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12 pages, 4715 KB

Open AccessFeature PaperArticle

Nitrogen-Doped Carbon Coated Zn_0.17Co_0.83P as a Highly Active and Stable Electrocatalyst for Hydrogen Evolution

by Guo-Ping Shen, Xiao-Mei Men, Si-Jia Guo, Na Xu and Bin Dong

Catalysts 2025, 15(11), 1071; https://doi.org/10.3390/catal15111071 - 12 Nov 2025

Abstract

Zeolitic imidazolate frameworks (ZIFs) can provide fascinating stereo morphology and tunable metal active sites, which plays an important role in the synthesis of various catalytic materials. However, it is still a problem to make use of these advantages to design efficient hydrogen evolution reaction (HER) catalysts. Herein, we use covalent coordination strategy to synthesize bimetallic Co_xZn_1−x(2-MeIM)₂ precursors with regular dodecahedral structures for providing uniform active sites and stable carbon skeleton. Furthermore, the ratio of Co and Zn atoms was optimized to balance the electron density and give full play to the synergistic catalytic effect. And then, the subsequent high temperature annealing process is used to construct the amorphous carbon layer, which can improve the overall stability of the material. The gas phase phosphating process realizes the transformation from ZIF material to metal phosphide resulting in enhanced hydrogen evolution activity. Finally, the optimized amorphous nitrogen-doped carbon (NC)-coated Zinc-doped cobalt phosphide (Zn_0.17Co_0.83P@NC) requires only 237.60 mV to reach the current density of 10 mA cm⁻² in alkaline medium, which is 223.22 mV lower than that of CoP, and has a stability of up to 18 h. This work provides a reference for the rational design of efficient and stable compound electrocatalysts for alkaline hydrogen evolution based on the bimetallic ZIF as a precursor. Full article

(This article belongs to the Special Issue Non-Noble Metal Electrocatalytic Materials for Clean Energy)

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23 pages, 3517 KB

Open AccessFeature PaperReview

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

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

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

Abstract

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

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

11 pages, 1577 KB

Open AccessFeature PaperArticle

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

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

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

Abstract

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

(This article belongs to the Section Catalytic Materials)

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18 pages, 7034 KB

Open AccessArticle

Effect of a Grinding Method in the Preparation of CuO-ZnO-Al₂O₃@HZSM-5 Catalyst for CO₂ Hydrogenation

by He Jia, Tao Du, Yingnan Li, Peng Chen, Rui Xiang, Zhaoyi Sun, Bowen Yang and Yisong Wang

Catalysts 2025, 15(11), 1068; https://doi.org/10.3390/catal15111068 - 10 Nov 2025

Abstract

There are many obstacles to the industrial application of CO₂ hydrogenation reduction technology, the most important of which is the high economic cost. The purpose of this study is to explore the interaction mechanism between the active component CuO-ZnO-Al₂O₃(CZA) and the zeolite carrier Zeolite Socony Mobil-5(ZSM-5), screen the simplified preparation method of catalysts with high catalytic performance, and further promote the industrial application of CO₂ hydrogenation reduction technology. In this study, the effects of the gas velocity of the feedstock, the reaction temperature, the content of acidic sites in the carrier, the filling amount of active component, and the mixing mode of the active component and the carrier on catalytic CO₂ hydrogenation reduction were investigated. The structure of the catalysts was analyzed by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The catalyst surface properties were analyzed by X-ray photoelectron spectroscopy (XPS), ammonia temperature programmed desorption (NH₃-TPD), hydrogen temperature programed reduction (H₂-TPR) and other characterization methods. The research found that the grinding treatment led to the insertion of CZA between ZSM-5 zeolite particles in CZA@HZ5-20-GB, which was prepared via grinding both CZA and H-ZSM-5 with an Si/Al ratio of 20, inhibiting the action of strongly acidic sites in the zeolite, resulting in only CO and MeOH in the catalytic products, with no Dimethyl Ether (DME) generation. Full article

(This article belongs to the Special Issue Catalysis on Stable Molecules (CO₂, CO, CH₄, N₂, NH₃) Activation and Their Transformation, 3rd Edition)

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41 pages, 15950 KB

Open AccessFeature PaperReview

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

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

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

Abstract

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

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

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21 pages, 2517 KB

Open AccessFeature PaperArticle

Genetic and Process Engineering for the Simultaneous Saccharification and Biocatalytic Conversion of Lignocellulose for Itaconic Acid Production by Myceliophthora thermophila

by Renwei Zhang, Chenbiao Zhao, Yuchen Ning, Jianqi Deng, Fang Wang, Huan Liu and Li Deng

Catalysts 2025, 15(11), 1066; https://doi.org/10.3390/catal15111066 - 9 Nov 2025

Abstract

Itaconic acid (IA), one of the top twelve renewable platform chemicals, is a key precursor for polymer synthesis. Here, we engineered Myceliophthora thermophila for efficient consolidated biocatalytic IA production from lignocellulose by introducing the heterologous IA pathway (cis-aconitic acid decarboxylase (CAD), mitochondrial tricarboxylic transporter (MTT), major facilitator superfamily transporter (MFS) from Aspergillus terreus), and boosting CAD expression and precursor supply. A critical issue was temperature mismatch: optimal fungal growth vs. CAD activity. Transcriptomics analysis identified reduced expression of glycolytic rate-limiting enzymes (fructose-bisphosphate aldolase, FBA; phosphofructokinase, PFK) at 40 °C. Overexpressing these enzymes in strain IA32 generated strain IA41 (with 3.1-fold and 2.8-fold higher expression of pfk and fba, respectively), which accelerated glucose consumption by 53.2% and increased IA yield by 55.1% A two-stage temperature-shift strategy (45 °C for growth/saccharification, 40 °C for CAD activity) was developed. The engineered strain achieved 3.93 g/L IA in shake flasks and 10.51 g/L in corncob fed-batch fermentation—the highest reported titer for consolidated lignocellulose-to-IA processes. This establishes M. thermophila as a robust platform for cost-effective IA production from lignocellulose. Full article

(This article belongs to the Section Biocatalysis)

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17 pages, 2675 KB

Open AccessArticle

Biochar-Modified TiO₂ Composites: Enhanced Optical and Photocatalytic Properties for Sustainable Energy and Environmental Applications

by Fatma. F. Alharbi, Taymour A. Hamdalla, Hanan Al-Ghamdi, Badriah Albarzan and Ahmed. A. Darwish

Catalysts 2025, 15(11), 1065; https://doi.org/10.3390/catal15111065 - 9 Nov 2025

Abstract

Enhancing TiO₂ performance is essential for advancing photocatalysis, environmental remediation, and energy conversion technologies. In this work, nanosized TiO₂ was modified with biochar (BC) derived from red sea algae at different loadings (0, 5, 10, and 15 wt%). Structural analysis confirmed that TiO₂ maintained its crystalline framework while biochar introduced additional amorphous features and modified surface morphology. Optical measurements revealed a redshift in the absorption edge and tunable bandgap values (3.28–3.72 eV), accompanied by increases in refractive index and extinction coefficient, indicating enhanced light–matter interactions. Electrochemical studies demonstrated that the TiO₂/5 wt% BC composite exhibited the lowest charge-transfer resistance and highest peak current, reflecting superior conductivity. Photocatalytic tests showed that TiO₂/5 wt% BC achieved nearly 84% degradation of methylene blue within 150 min under visible-light irradiation, with stable reusability over multiple cycles. These findings demonstrate that moderate biochar incorporation (5 wt%) optimally enhances the physicochemical, electrochemical, and photocatalytic properties of TiO₂, making it a promising candidate for wastewater treatment, solar-driven catalysis, and sustainable energy applications. Full article

(This article belongs to the Special Issue Advances in Catalysis for Sustainable Energy and Environmental Remediation, 2nd Edition)

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14 pages, 3279 KB

Open AccessArticle

Additive Manufacturing of CaO-Pt/Al₂O₃ Structured Catalysts for Cyclohexane Dehydrogenation

by Panfeng Wang, Zhaoyang Lu, Xiang Qi, Wenting Xing, Yubo Shi and Jiapo Yan

Catalysts 2025, 15(11), 1064; https://doi.org/10.3390/catal15111064 - 8 Nov 2025

Abstract

The dehydrogenation of cyclohexane is of vital importance for the production of Nylon-6 and Nylon-66, as it enhances atom utilization efficiency. Ca-doped platinum catalysts have been employed in alkane dehydrogenation due to their ability to selectively activate C–H bonds while minimizing C–C bond cleavage. However, owing to their limited selectivity toward cyclohexene, Pt-Ca/Al₂O₃ catalysts have not been widely adopted in the field of partial dehydrogenation to alkenes. In this work, Al₂O₃ supports are fabricated using the direct ink writing (DIW) 3D printing technique, incorporating designed channels. After impregnation and calcination at 550 °C, the distribution of active species, surface acidity, and basicity are optimized, resulting in a cyclohexene yield of 8.9%. The cyclohexene yield and stability of the 3D-printed catalysts are significantly higher than those of the granular catalyst, attributed to enhanced heat and mass transfer performance facilitated by the internal channels. Full article

(This article belongs to the Section Catalytic Materials)

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4 pages, 144 KB

Open AccessEditorial

Recent Advances in Photocatalysis for Environmental Applications

by Vesna Lojpur

Catalysts 2025, 15(11), 1063; https://doi.org/10.3390/catal15111063 - 7 Nov 2025

Abstract

The most important resource for the survival of all living beings is water [...] Full article

(This article belongs to the Special Issue Recent Advances in Photocatalysis for Environmental Applications)

38 pages, 4591 KB

Open AccessFeature PaperReview

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

by Zhihua Wu, Jing Gao and Yongbo Kuang

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

Abstract

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

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

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27 pages, 8744 KB

Open AccessFeature PaperReview

Recent Progress in WO₃-Based Photo(electro)-Catalysis Systems for Green Organic Synthesis and Wastewater Remediation: A Review

by Linghua Bu, Lingxiao Tan, Sai Zhang, Kun Xu and Chengchu Zeng

Catalysts 2025, 15(11), 1061; https://doi.org/10.3390/catal15111061 - 6 Nov 2025

Abstract

Photo(electro)-catalysis has increasingly attracted attention from researchers due to its wide applications in green chemical transformation, including organic synthesis and environmental remediation. As a promising candidate, the n-type semiconductor WO₃ possesses a suitable bandgap (~2.6 eV), good visible-light response, high chemical stability, and multi-electron transfer capability, thus endowing it with enormous potential in heterogeneous photocatalysis (PC) and photoelectrocatalysis (PEC) to address environment and energy issues. In this review, the recent research progress of WO₃-based photo(electro)-catalysts is examined and systematically summarized with regard to construction strategies and various application scenarios. To start with, the research background, functionalization methods and possible reaction mechanisms for WO₃ are introduced in depth. Key influencing factors, including light absorption capacity, charge carrier separation, and reusability, are also analyzed. Then, diverse applications of WO₃ for the elimination of organic pollutants (e.g., persistent organic pollutants and polymeric wastes) and green organic synthesis (i.e., oxidation, reduction, and other reactions) are intentionally discussed to underscore their vast potential in photo(electro)-catalytic performance. Finally, future challenges and insightful perspectives are proposed to explore effective WO₃-based materials. This comprehensive review aims to offer profound insights into innovative exploration of high-performance WO₃ semiconductor catalysts and guide new researchers in this field to better understand their vital roles in green organic synthesis and hazardous pollutants removal. Full article

(This article belongs to the Special Issue Advanced Photo/Electrocatalysts for Environmental Purification)

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39 pages, 6345 KB

Open AccessReview

Research Progress on Zeolite-Type High-Temperature NH₃-SCR Catalysts

by Xuewen Mu, Xue Bian, Yuting Bai, Meng Zha, Yu Huang and Jing Wei

Catalysts 2025, 15(11), 1060; https://doi.org/10.3390/catal15111060 - 6 Nov 2025

Abstract

Gas turbines operate at exhaust gas temperatures exceeding 500 °C. Vanadium-based catalysts encounter challenges in NH₃-SCR denitrification due to vanadium volatilization and titanium dioxide support phase transition at high temperatures. This restricts the effective denitrification temperature range to 300~400 °C, falling short of gas turbine denitrification requirements. Zeolite-supported catalysts, known for their high specific surface area, abundant acid sites, and stable framework structure, demonstrate superior catalytic activity and hydrothermal stability at high temperatures. This review synthesizes recent advancements in high-temperature catalysts utilizing ZSM-5, Beta, SSZ-13, and SAPO-34 zeolites as supports. It elucidates the interaction mechanisms between active components (e.g., transition metals Fe, Cu, W, rare earth elements) and zeolite supports. Furthermore, it examines variations in denitrification performance through the lens of the high-temperature NH₃-SCR reaction mechanism, offering valuable insights for high-temperature denitrification catalyst development. Full article

(This article belongs to the Section Industrial Catalysis)

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18 pages, 1902 KB

Open AccessArticle

Genomic Identification of the Levansucrase Operon in Novel Bacillus velezensis HL25 in Sucrose Utilizing Pathway and Functional Characterization of Its Levansucrase

by Hataikarn Lekakarn, Jiruchaya Chaisuriyaphun, Ruethaikan Junsuk, Putanat Kornpitak, Teeranart Komonmusik, Wuttichai Mhuantong and Benjarat Bunterngsook

Catalysts 2025, 15(11), 1059; https://doi.org/10.3390/catal15111059 - 6 Nov 2025

Abstract

Levan and levan-type fructooligosaccharides (L-FOSs) are non-digestible fructans with prebiotic properties that promote gut microbiota growth. This study presents the first genomic analysis of a Bacillus velezensis HL25 strain with high fructan-producing efficiency, revealing genes involved in sucrose utilization and fructan biosynthesis. A putative levansucrase operon was identified in the HL25 genome, consisting of the sacB levansucrase gene classified in GH68 subfamily 1 and the following three GH32 genes: endo-levanase (lev), β-fructofuranosidase (ffase), and sucrose-6-phosphate hydrolase (scrB). Remarkably, sugars involved in levan biosynthesis are proposed to be transported through three distinct systems: a multiple-component ABC sugar transporter, a glucose/H⁺ symporter, and glucose- and fructose-specific phosphotransferase systems (PTS). Subsequently, recombinant HL25SacB levansucrase exhibited optimal activity at 40 °C and pH 5.0 in 50 mM sodium acetate buffer. The enzyme demonstrates high specificity in converting sucrose into a mixture of short-chain FOSs (DP 2–4) and levan, achieving a 62.5% conversion rate at 30 °C with 200 g/L sucrose over 24 h. These findings demonstrate the potential of this B. velezensis HL25 strain as an efficient whole-cell biocatalyst and highlight the applicability of the recombinant HL25SacB enzyme as a promising tool for sustainable production of FOSs and levan. Full article

(This article belongs to the Section Biocatalysis)

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1 pages, 126 KB

Open AccessCorrection

Correction: Ji et al. The Impact of Bilirubin on 7α- and 7β-Hydroxysteroid Dehydrogenases: Spectra and Docking Analysis. Catalysts 2023, 13, 965

by Qingzhi Ji, Jiamin Chen, Luping Zhu, Ruiyao Wang and Bochu Wang

Catalysts 2025, 15(11), 1058; https://doi.org/10.3390/catal15111058 - 6 Nov 2025

Abstract

Following publication, concerns were raised regarding the peer-review process related to the publication of this article [...] Full article

19 pages, 13019 KB

Open AccessArticle

Advanced Ozone Oxidation Systems for Organic Pollutant Degradation: Performance Evaluation and Mechanism Insights

by Liangrui Xiang, Shuang Yang and He Guo

Catalysts 2025, 15(11), 1057; https://doi.org/10.3390/catal15111057 - 6 Nov 2025

Abstract

Textile dyeing wastewater, rich in recalcitrant organic compounds such as azo and anthraquinone dyes, poses significant environmental concerns. This study investigates the degradation of methyl orange (MO) using two ozone (O₃) oxidation systems—O₃/H₂O₂ and O₃/K₂S₂O₈—and analyzes the degradation products and toxicity via ESR characterization. The O₃/K₂S₂O₈ system shows a higher removal rate in the initial stage (<4 min) due to rapid ·SO₄^- radical generation. However, O₃/H₂O₂ produces more ·OH radicals, leading to better overall degradation performance. The O₃/K₂S₂O₈ system is more effective for pollutants with electron-rich groups, such as Congo red and sulfamethoxazole, while O₃/H₂O₂ performs better in natural lake water. Mechanistic studies reveal that ·O₂^- is the dominant oxidizing species in O₃/H₂O₂, while ·SO₄^- and ·O₂^- dominate in O₃/K₂S₂O₈. The toxicity of degradation products is assessed, showing lower bioaccumulation and developmental toxicity in most intermediate products compared to MO. This research provides valuable insights into the use of combined ozonation-peroxidation coupling technology for effective wastewater treatment. Full article

(This article belongs to the Special Issue Cutting-Edge Catalytic Strategies for Organic Pollutant Mitigation)

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14 pages, 2711 KB

Open AccessArticle

Mechanistic Insights into Radical-Mediated Moxifloxacin Degradation Using Ultrasound-Assisted Persulfate Activation by Iron-Rich Soil

by Mahamadou Kamagate, Fekri Abdulraqeb Ahmed Ali, Traore Lancine, Coulibaly Gnougon Nina, Amine Aymen Assadi, Coulibaly Lacina, Goné Droh Lanciné and Oussama Baaloudj

Catalysts 2025, 15(11), 1056; https://doi.org/10.3390/catal15111056 - 5 Nov 2025

Abstract

Fluoroquinolones are a major issue in aquatic ecosystems due to their persistence, potential to induce antibiotic resistance, and inability to be effectively removed using conventional treatment methods. Several advanced oxidation processes have been studied for their degradation; however, there is still a lack of knowledge about their degradation mechanisms and the precise roles played by reactive species. In this context, the study investigated the heterogeneous activation of persulfate (PS) to degrade fluoroquinolones (FQs), such as moxifloxacin (MFX), in iron-rich soil (Cat) under ultrasound irradiation (US). The analysis of the soil catalyst revealed the presence of quartz (35%), iron oxides (33%), and alumina (26%) as the predominant constituents of the sample. The mineral phase analysis indicated the presence of magnetite, hematite, and alumina. Then, the outcomes of the specific surface area, micropore volume, and total pore volume were determined to be 19 m² g⁻¹, 6 m³ g⁻¹ and 9.10 m³ g⁻¹, respectively. The MFX/PS/US/Cat system demonstrated 89% degradation and 56% mineralization after 300 min. However, the optimized concentrations of i-PrOH, t-BuOH, and CHCl₃ were 50, 100, and 50 mM, respectively, in order to trap the radicals SO₄^•−, OH^•, and O₂^•−. The study examined the individual contributions of SO₄^•−, OH^•, and O₂^•− radicals to the overall process of MFX degradation. The results indicated that SO₄^•− was the primary radical, with a contribution of 52%, followed by OH^• with 43%, and O₂^•− with 5%. Finally, the investigation revealed that laterite exhibited both good catalytic activity and reusability over several cycles. The development of this new process could stimulate the creation of cost-effective technology for water remediation through the effective removal of fluoroquinolones. Full article

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

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14 pages, 1314 KB

Open AccessFeature PaperArticle

Degradation of Atrazine to Cyanuric Acid by an Encapsulated Enzyme Cascade

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

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

Abstract

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

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

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18 pages, 2496 KB

Open AccessFeature PaperArticle

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

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

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

Abstract

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

(This article belongs to the Section Nanostructured Catalysts)

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Open AccessFeature PaperArticle

Insight into the Au/CoAlO_x Catalyst with Spinel Structure for Efficient Oxidation of Benzyl Alcohol

by Meihui Bao, Sen Zhang, Wenhao Yang, Hao Liu, Shaojie Li, Jingjie Luo and Changhai Liang

Catalysts 2025, 15(11), 1053; https://doi.org/10.3390/catal15111053 - 4 Nov 2025

Abstract

Selective oxidation of benzyl alcohol to benzaldehyde is crucial for sustainable chemical synthesis, which provides the atom-economical and environmentally benign pathways. In this work, we used the in situ reduction immobilization to synthesize a series of Au nanoparticles supported by CoAlO_x support with spinel structure for alkali-free oxidation of benzyl alcohol. The synthesis methodology was preliminarily optimized and the influence of Co/Al molar ratio in Au/CoAlO_x on the catalytic performances was subsequently revealed based on characterizations. Results suggested that the electronic interaction between Au and CoAlO_x can be regulated and maximized under the Co/Al ratio of 3. It became a main factor to modulate the dispersion of Au nanoparticles, surface chemical composition, as well as the oxygen adsorption/activation ability. Benefiting from such synergistic interaction, the optimized Au/Co₃AlO_x catalyst achieved 86.1% BnOH conversion under 99.9% benzaldehyde selectivity with well-maintained structural stability under recycle tests. This work provides a rational design strategy for developing highly efficient gold catalysts with well-constructed Au-support interfaces for the alkali-free oxidation of alcohol. Full article

(This article belongs to the Special Issue Catalysis in C−H and C−C Bond Activation)

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