Catalysts

16 pages, 4730 KB

Open AccessArticle

Carbon and Silica Supports Enhance the Durability and Catalytic Performance of Cobalt Oxides Derived from Cobalt Benzene-1,3,5-Tricarboxylate Complex

by Hassan H. Hammud, Waleed A. Aljamhi, Kawther AlAbdullah, Muhammad Humayun and Ihab Shawish

Catalysts 2025, 15(9), 881; https://doi.org/10.3390/catal15090881 (registering DOI) - 13 Sep 2025

Abstract

Addressing the urgent need for robust and sustainable catalysts to detoxify nitroaromatic pollutants, this study introduces a novel approach for synthesizing cobalt oxide nanocomposites via pyrolysis of cobalt benzene-1,3,5-tricarboxylate. By integrating porous carbon (PC) and nano silica (NS) supports with Co₃O [...] Read more.

Addressing the urgent need for robust and sustainable catalysts to detoxify nitroaromatic pollutants, this study introduces a novel approach for synthesizing cobalt oxide nanocomposites via pyrolysis of cobalt benzene-1,3,5-tricarboxylate. By integrating porous carbon (PC) and nano silica (NS) supports with Co₃O₄ to form (Co₃O₄/PC) and (Co₃O₄/NS), we achieved precise morphological control, as evidenced by SEM and TEM analysis. SEM revealed 80–500 nm Co₃O₄ microspheres, 300 nm Co₃O₄/PC microfibers, and 2–5 µm Co₃O₄/NS spheres composed of 100 nm nanospheres. TEM further confirmed the presence of ~15 nm nanoparticles. Additionally, FTIR spectra exhibited characteristic Co–O bands at 550 and 650 cm⁻¹, while UV–Vis absorption bands appeared in the range of 450–550 nm, confirming the formation of cobalt oxide structures. Catalytic assays toward p-nitrophenol reduction revealed exceptional kinetics (k = 0.459, 0.405, and 0.384 min⁻¹) and high turnover numbers (TON = 5.1, 6.7, and 6.3 mg 4-NP reduced per mg of catalyst), outperforming most of the recently reported systems. Notably, both supported catalysts retained over 95% activity after two regeneration cycles. These findings not only fill a gap in the development of efficient, regenerable cobalt-based catalysts, but also pave the way for practical applications in environmental remediation. Full article

(This article belongs to the Special Issue Environmental Catalysis and Nanomaterials for Water Pollution Control)

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11 pages, 1561 KB

Open AccessArticle

Enhanced Peroxydisulfate Activation by Co-Doping of Nitrogen, Chlorine, and Iron: Preparation, Synergistic Effects, and Application

by Zhipeng Li, Hao Zhang, Wanjiang Guo, Tan Meng, Hongru Cui and Chao Ma

Catalysts 2025, 15(9), 880; https://doi.org/10.3390/catal15090880 (registering DOI) - 13 Sep 2025

Abstract

The continuous increase in solid waste poses a significant environmental challenge. Pyrolysis represents a crucial technology for the valorization of solid waste. As the primary product, biochar has found applications in numerous fields and garnered significant scientific interest. This study investigated the potential [...] Read more.

The continuous increase in solid waste poses a significant environmental challenge. Pyrolysis represents a crucial technology for the valorization of solid waste. As the primary product, biochar has found applications in numerous fields and garnered significant scientific interest. This study investigated the potential of NH₄Cl and FeCl₃ for modifying biochar. The resultant modified biochar achieved over 70% sulfamethoxazole (SMX) degradation within 30 min. The incorporation of NH₄Cl and FeCl₃ facilitated the formation of pyridinic nitrogen (N), graphitic nitrogen (N), and Fe(II) 1/2p, while the concomitant increase in persistent free radicals facilitated enhanced electron transfer rates. Notably, NH₄Cl/FeCl₃-modified biochar demonstrated superior efficacy compared with alternative activation techniques for real wastewater treatment. This study presents a novel material for persulfate (PDS)-based advanced oxidation processes, while also offering a cost-effective strategy for solid waste disposal. Full article

(This article belongs to the Special Issue Catalytic Processes for Environmental Remediation and Resource Recycling)

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11 pages, 2280 KB

Open AccessArticle

Amorphous MoSx Nanosheets with Abundant Interlayer Dislocations for Enhanced Photolytic Hydrogen Evolution Reaction

by Xuyang Xu, Zefei Wu, Weifeng Hu, Ning Sun, Zijun Li, Zhe Feng, Yinuo Zhao and Longlu Wang

Catalysts 2025, 15(9), 879; https://doi.org/10.3390/catal15090879 (registering DOI) - 13 Sep 2025

Abstract

Transition metal dichalcogenides (TMSs), exemplified by molybdenum disulfide (MoS₂), exhibit significant potential as alternatives to noble metals (e.g., Pt) for the hydrogen evolution reaction (HER). However, conventional synthesis methods of MoSx often suffer from active site loss, harsh reaction conditions, or [...] Read more.

Transition metal dichalcogenides (TMSs), exemplified by molybdenum disulfide (MoS₂), exhibit significant potential as alternatives to noble metals (e.g., Pt) for the hydrogen evolution reaction (HER). However, conventional synthesis methods of MoSx often suffer from active site loss, harsh reaction conditions, or undesirable oxidation, limiting their practical applicability. The development of MoSx with high-density active sites remains a formidable challenge. Herein, we propose a novel strategy employing [Mo₃S₁₃]²⁻ clusters as precursors to construct three-dimensional amorphous MoSx nanosheets through optimized hydrothermal and solvent evaporation-induced self-assembly approaches. Comprehensive characterization confirms the material’s unique amorphous lamellar structure, featuring preserved [Mo₃S₁₃]²⁻ units and engineered interlayer dislocations that facilitate enhanced electron transfer and active site exposure. This work not only establishes [Mo₃S₁₃]²⁻ clusters as effective building blocks for high-performance MoSx catalysts, but also provides a scalable and environmentally benign synthesis route for the large-scale production of such nanostructured a-MoSx. Our findings facilitate the rational design of non-noble HER catalysts via structural engineering, with broad implications for energy conversion technologies. Full article

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15 pages, 5343 KB

Open AccessArticle

Superhydrophobic Cerium-Based Metal–Organic Frameworks/Polymer Nanofibers for Water Treatment

by Hani Nasser Abdelhamid and Samar A. Salim

Catalysts 2025, 15(9), 878; https://doi.org/10.3390/catal15090878 (registering DOI) - 12 Sep 2025

Abstract

In this study, cerium-based metal–organic frameworks (MOFs), cerium terephthalate (CeTPA), were synthesized and incorporated into nanofibers via electrospinning using poly(methyl methacrylate) (PMMA). The synthesized materials were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), diffuse reflectance spectroscopy [...] Read more.

In this study, cerium-based metal–organic frameworks (MOFs), cerium terephthalate (CeTPA), were synthesized and incorporated into nanofibers via electrospinning using poly(methyl methacrylate) (PMMA). The synthesized materials were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and Tauc plot analysis. The electrospun CeTPA nanofibers exhibited superhydrophobic properties, with water contact angles exceeding 150°. The adsorption and catalytic performance of the nanofibers were assessed for dye removal using Congo red (CR) and methylene blue (MB) as model organic pollutants. Adsorption studies demonstrated negligible dye uptake due to the hydrophobicity of the fibers, while catalytic degradation experiments in the presence of hydrogen peroxide (H₂O₂) showed significant degradation of CR but limited effectiveness against MB, offering high selectivity toward anionic dyes. Structural and optical characterizations confirmed the stability and catalytic activity of CeTPA nanofibers, highlighting their potential for selective dye degradation in wastewater treatment applications. Full article

(This article belongs to the Special Issue Advanced Catalysis Technologies Using Metal-Organic Frameworks (MOFs))

16 pages, 5209 KB

Open AccessArticle

Elucidating the Synergism by Applying Ni-Cu/Cr₂O₃ Catalysts for Green Methanol Fuel Synthesis by CO₂ Hydrogenation

by Israf Ud Din, Abdulrahman I. Alharthi, Mshari A. Alotaibi, Md Afroz Bakht, Rida Ihsan, Tooba Saeed, Ho Soon Min and Abdul Naeem

Catalysts 2025, 15(9), 877; https://doi.org/10.3390/catal15090877 (registering DOI) - 12 Sep 2025

Abstract

The CO₂ hydrogenation process is thought to be one of the feasible methods for producing methanol fuel, which might be used to fulfill future energy demands. Improving the catalytic efficiency and understanding of the process are essential elements for the viability of [...] Read more.

The CO₂ hydrogenation process is thought to be one of the feasible methods for producing methanol fuel, which might be used to fulfill future energy demands. Improving the catalytic efficiency and understanding of the process are essential elements for the viability of CO₂ conversion routes. Here, a co-precipitation method was used to synthesize Ni-Cu bimetallic catalysts supported by chromium oxide (Cr₂O₃). To examine nickel (Ni)’s promoting role, the synthesized catalysts were incorporated with different concentrations of Ni. The N₂ adsorption–desorption isotherm exposed the mesoporous nature of Cr₂O₃-based Ni-Cu catalysts. A Fourier Transform Infrared (FTIR) spectroscopy investigation revealed the effective doping of Ni-Cu metal oxides on the surface of Cr₂O₃ by instigating an FTIR absorption band in the region associated with the FTIR absorption of metal oxides. The uniform morphology and homogenous, as well as highly dispersed, form of both Ni and Cu metal were recorded using a Field Emission Scanning Electron Microscope (FESEM) and X-ray Diffraction (XRD) techniques. The surface chemistry, metal–metal, and metal–support interactions of the Ni-Cu/Cr₂O₃ catalysts were disclosed via temperature program reduction (TPR) as well as X-ray photoelectron spectroscopy (XPS). The synergism between the Ni and Cu metals was revealed using both XPS and TPR techniques, which resulted in improving the catalytic profile of Ni-Cu/Cr₂O₃ catalysts. The activity data obtained by applying a slurry reactor demonstrated the active profile of Ni for CO₂ reduction to methanol in terms of the methanol synthesis rate. The promoting role of Ni was established by observing the progressing and linear increase in methanol selectivity by Ni enrichment to the Ni-Cu/Cr₂O₃ catalysts. Structure and activity studies recognized the promoting role of Ni by experiencing metal–metal and metal–support interactions with highly dispersed metal oxides over the Cr₂O₃ support in the current case. Full article

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

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11 pages, 1607 KB

Open AccessArticle

Iron-Doped NiSe₂ and Its Enhanced Oxygen Evolution Reaction Activity

by Lijie Sun, Yaqun Mi and Bo Li

Catalysts 2025, 15(9), 876; https://doi.org/10.3390/catal15090876 (registering DOI) - 12 Sep 2025

Abstract

Doping a third element or external functional components into binary alloy nanostructured catalysts typically significantly enhances their electrocatalytic performance. This study demonstrates that doping nickel selenide (NiSe₂) with approximately

10 a t %

iron (Fe) is an effective strategy for [...] Read more.

Doping a third element or external functional components into binary alloy nanostructured catalysts typically significantly enhances their electrocatalytic performance. This study demonstrates that doping nickel selenide (NiSe₂) with approximately

10 a t %

iron (Fe) is an effective strategy for improving its oxygen evolution reaction (OER) catalytic activity. The resulting Ni_0.9Fe_0.1Se₂ undergoes a structural transformation from its original nanodendritic morphology and exhibits outstanding OER catalytic performance in alkaline media. It achieves a low overpotential of

231 m V

at a current density of

10 m A {c m}^{- 2}

, which is approximately

30 %

lower than that of NiSe₂ (

301 m V

). The Tafel slope of Ni_0.9Fe_0.1Se₂ is

116 m V {d e c}^{- 1}

. However, degradation observed after 5 h of stability testing suggests that the doping process requires further optimization. Full article

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19 pages, 3413 KB

Open AccessFeature PaperArticle

Activated Carbon-Modified Porous Carbon Nitride Decorated with Molybdenum Disulfide for Enhanced Photocatalytic Degradation of Rhodamine B

by Kunyang Li, Di Wang, Ning Tang, Zhou Zhou, Wen Zhang, Bohan Liu and Yiying Yue

Catalysts 2025, 15(9), 875; https://doi.org/10.3390/catal15090875 - 12 Sep 2025

Viewed by 24

Abstract

Photocatalytic technology offers significant potential for pollutant remediation through efficient, cost-effective mineralization but faces inherent limitations, including catalyst agglomeration and rapid charge recombination. To address these challenges, we developed activated carbon-modified porous graphitic carbon nitride (APCN) synthesized through the co-polycondensation of dicyandiamide with [...] Read more.

Photocatalytic technology offers significant potential for pollutant remediation through efficient, cost-effective mineralization but faces inherent limitations, including catalyst agglomeration and rapid charge recombination. To address these challenges, we developed activated carbon-modified porous graphitic carbon nitride (APCN) synthesized through the co-polycondensation of dicyandiamide with NH₄Cl and fir-wood-derived activated carbon (AC). The incorporated AC effectively prevented the agglomeration of carbon nitride frameworks, thereby enhancing the specific surface area (S_BET) of APCN. This matrix was subsequently composited with hydrothermally prepared (1T/2H) mixed-phase MoS₂ through ultrasonication, forming a MoS₂/APCN heterostructure. Characterizations including Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and N₂ adsorption–desorption isotherms (BET) confirmed that MoS₂ was successfully loaded onto APCN via an ultrasonic synthesis method. The composite exhibited outstanding photocatalytic activity, degrading 95.5% RhB in 40 min (pH = 7) and 97.4% in 25 min (pH = 3.5), with 87.3% efficiency retention after four cycles (pH = 7). Crucially, AC enhanced visible-light absorption and functioned as an electron-mediating component. Photoelectrochemical analyses and radical-trapping experiments confirmed a direct Z-scheme charge transfer mechanism, wherein conductive AC accelerates electron transport and suppresses carrier recombination. This study establishes both an efficient RhB degradation photocatalyst and a sustainable strategy for valorizing agricultural waste in advanced material design. Full article

(This article belongs to the Section Photocatalysis)

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27 pages, 5687 KB

Open AccessArticle

Citrus aurantiifolia Peel-Facilitated Synthesis of Zinc Oxide, Interfaced with Biomass-Assisted Graphene Oxide for Enhanced Photocatalytic Degradation of Dye

by Hayfa Alajilani Abraheem Jamjoum, Khalid Umar, Saima Khan Afridi, Hilal Ahmad, Tabassum Parveen and Uzma Haseen

Catalysts 2025, 15(9), 874; https://doi.org/10.3390/catal15090874 - 12 Sep 2025

Viewed by 15

Abstract

This study synthesizes zinc oxide (ZnO) and graphene oxide (GO) nanomaterials using a green and sustainable method. ZnO nanoparticles were synthesized from lime peel extract, while GO was obtained utilizing oil palm empty fruit bunch (OPEFB) fibre. The resulting ZnO/GO nanocomposites were characterized [...] Read more.

This study synthesizes zinc oxide (ZnO) and graphene oxide (GO) nanomaterials using a green and sustainable method. ZnO nanoparticles were synthesized from lime peel extract, while GO was obtained utilizing oil palm empty fruit bunch (OPEFB) fibre. The resulting ZnO/GO nanocomposites were characterized using Fourier transform infrared (FTIR), photoluminescence (PL), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible diffuse reflectance spectroscopy (UVDRS), and Raman spectroscopy (RS), confirming their successful synthesis, reduced particle size, altered band gap, and enhanced charge separation properties. The photocatalytic activities of the ZnO/GO nanocomposites were evaluated for MB degradation under visible light. Notably, the ZnO/GO (7%) composite exhibited better degradation efficiency (87% in 90 min) compared to commercial and synthesized ZnO. The study also optimized key parameters including catalyst loading (1 g L⁻¹), initial dye concentration (0.03 mM), and pH (pH 12 showed highest efficiency). The kinetic studies confirmed a pseudo-first-order reaction, with ZnO/GO (7%) showing the highest rate constant (0.0208 min⁻¹). The scavenger tests identified hydroxyl radicals (^•OH) as the dominant reactive species. This research presents a sustainable and efficient approach for wastewater treatment, utilizing waste materials to produce high-performance photocatalysts for environmental remediation. Full article

(This article belongs to the Special Issue Novel Advancements Towards Nanocomposite Synthesis and Their Potential Application in Photocatalysis, 2nd Edition)

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20 pages, 3592 KB

Open AccessArticle

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

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

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

Viewed by 28

Abstract

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

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

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

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28 pages, 2387 KB

Open AccessFeature PaperArticle

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

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

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

Viewed by 186

Abstract

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

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

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

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36 pages, 5122 KB

Open AccessReview

Advanced Electrocatalyst Supports for High-Temperature Proton Exchange Membrane Fuel Cells: A Comprehensive Review of Materials, Degradation Mechanisms, and Performance Metrics

by Qingqing Liu, Huiyuan Liu, Weiqi Zhang, Qian Xu and Huaneng Su

Catalysts 2025, 15(9), 871; https://doi.org/10.3390/catal15090871 - 11 Sep 2025

Viewed by 216

Abstract

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) offer distinct advantages over their low-temperature counterparts. However, their commercial viability is significantly hampered by durability challenges stemming from electrocatalyst support degradation in the corrosive phosphoric acid environment. This review provides a comprehensive analysis of advanced [...] Read more.

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) offer distinct advantages over their low-temperature counterparts. However, their commercial viability is significantly hampered by durability challenges stemming from electrocatalyst support degradation in the corrosive phosphoric acid environment. This review provides a comprehensive analysis of advanced strategies to overcome this critical durability issue. Two main research directions are explored. The first involves engineering more robust carbon-based materials, including graphitized carbons, carbon nanostructures (nanotubes and graphene), and heteroatom-doped carbons, which enhance stability by modifying the carbon’s intrinsic structure and surface chemistry. The second direction focuses on replacing carbon entirely with intrinsically stable non-carbonaceous materials. These include metal oxides (e.g., TiO₂, SnO₂), transition metal carbides (e.g., WC, TiC), and nitrides (e.g., Nb₄N₅). For these non-carbon materials, a key focus is on overcoming their typically low electronic conductivity through strategies such as doping and the formation of multi-component composites. The analysis benchmarks the performance and durability of these advanced supports, concluding that rationally designed composite materials, which combine the strengths of different material classes, represent the most promising path toward developing next-generation, long-lasting catalysts for HT-PEMFCs. Full article

(This article belongs to the Special Issue Carbon-Based Materials Catalysts for Energy and Hydrogen Productions)

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22 pages, 2040 KB

Open AccessReview

Catalytic Carboxylation of Terminal Alkynes with CO₂: An Overview

by Valeria Myakota, Anna Strekalova, Anastasiya Shesterkina, Olga Kirichenko, Alexander Kustov and Leonid Kustov

Catalysts 2025, 15(9), 870; https://doi.org/10.3390/catal15090870 - 11 Sep 2025

Viewed by 203

Abstract

A large amount of CO₂ is released into the atmosphere by energy and industrial plants resulting in significant environment impacts. A considerable effort went into decreasing CO₂ emissions. The carboxylation reaction of converting CO₂ with aromatic alkynes to important chemicals [...] Read more.

A large amount of CO₂ is released into the atmosphere by energy and industrial plants resulting in significant environment impacts. A considerable effort went into decreasing CO₂ emissions. The carboxylation reaction of converting CO₂ with aromatic alkynes to important chemicals such as carboxylic acids is one of the promising CO₂ utilization methods, and it can be performed in the catalytic or non-catalytic pathway. Our review article provides an overview of recent publications on the use of catalytic systems with different compositions and structures for the carboxylation of terminal alkynes by involving CO₂, and the effect of a solvent and base. Relying on the research results, the use of heterogeneous catalysts is the most effective. The advantage of catalytic systems is a lower reaction temperature and pressure. Heterogeneous silver-containing catalysts exhibit good yields of products and high selectivity. Moreover, the catalysts may lose their efficiency when interacting with moisture. It has been found that the most effective catalysts for the carboxylation of phenylacetylene with carbon dioxide as a carboxylating agent are copper-based catalysts. These catalysts are characterized by high activity and stability. We highlight the challenges of developing novel catalyst systems tuning catalytic properties. The future outlook and perspectives are also discussed. Full article

(This article belongs to the Special Issue Catalysis and Technology for CO₂ Capture, Conversion and Utilization)

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13 pages, 3665 KB

Open AccessArticle

Insight into the Structure–Activity Relationship of Delafossite Catalysts for Enhanced Peroxymonosulfate Activation and Pollutant Degradation

by Liya Li and Jiang Deng

Catalysts 2025, 15(9), 869; https://doi.org/10.3390/catal15090869 - 10 Sep 2025

Viewed by 258

Abstract

Delafossite compounds (general formula ABO₂) have gained attention as promising catalysts for advanced oxidation processes (AOPs) due to their excellent substrate compatibility. However, the specific role of redox-active B-site metal centers in their catalytic mechanisms remains insufficiently elucidated. In this work, [...] Read more.

Delafossite compounds (general formula ABO₂) have gained attention as promising catalysts for advanced oxidation processes (AOPs) due to their excellent substrate compatibility. However, the specific role of redox-active B-site metal centers in their catalytic mechanisms remains insufficiently elucidated. In this work, delafossite-type CuFeO₂ and CuMnO₂ catalysts were successfully synthesized via a one-step hydrothermal method and applied to peroxymonosulfate (PMS) activation to degrade ofloxacin (OFX) and methylene blue (MB). Catalytic performance assessments demonstrated that Mn substitution at the B site markedly enhanced the removal efficiency of OFX. Mechanistic studies involving structural characterization (XRD, BET, XPS) and quenching tests revealed that the enhanced activity originates from the promoted self-decomposition of PMS facilitated by the incorporated Mn, which boosts the formation of radical species (^•OH and SO₄^•−) due to the improved electrical conductivity resulting from manganese’s multivalent nature. By clarifying the influence of the B-site metal electronic structure, this study provides fundamental insights into PMS activation mechanisms and informs the rational design of highly efficient and stable delafossite-based catalysts. Full article

(This article belongs to the Special Issue Advanced Catalysis in Water Purification: Organics and Heavy Metals Removal)

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20 pages, 1377 KB

Open AccessArticle

Microwave-Assisted Synthesis of BiOI for Solar-Driven Environmental Remediation

by Adriana C. Mera, Juan Matos, Claudia Araya Vera and Alexander Alfonso Alvarez

Catalysts 2025, 15(9), 868; https://doi.org/10.3390/catal15090868 - 9 Sep 2025

Viewed by 452

Abstract

Bismuth oxyiodide (BiOI) microspheres were synthesized by a microwave-assisted solvothermal method at 126 °C in only 4 min, a significantly shorter reaction time than in previously reported works. The structural, surface, morphological, and optical properties of BiOI were analyzed and correlated with the [...] Read more.

Bismuth oxyiodide (BiOI) microspheres were synthesized by a microwave-assisted solvothermal method at 126 °C in only 4 min, a significantly shorter reaction time than in previously reported works. The structural, surface, morphological, and optical properties of BiOI were analyzed and correlated with the photocatalytic activity during the degradation of gallic acid (GA) and the photo-oxidation of nitric oxide (NO) in the aqueous and gas phases, respectively. The BiOI microspheres exhibited higher first-order apparent rate constants for GA and NO (0.188 min⁻¹ and 0.230 min⁻¹) than the benchmark TiO₂ P25 (0.101 min⁻¹ and 0.066 min⁻¹). In addition, in steady-state reaction conditions (after 10 min), BiOI achieved 86% degradation of GA instead of the 63% degradation observed with TiO₂ P25. Furthermore, at the same point in the reaction, the BiOI microspheres showed up to 65% NO conversion, while TiO₂ P25 only achieved 15%. Accordingly, the results suggest that the microwave-assisted solvothermal method provides significant advantages for rapid, low-cost, and eco-friendly synthesis of BiOI microspheres for photocatalytic remediation of polluted water and air. Full article

(This article belongs to the Section Photocatalysis)

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13 pages, 2388 KB

Open AccessArticle

DFT Study on the Addition Reaction Mechanism of Phenylacetylene and NHC–Borane Catalyzed by DTBP

by Han-Wei-Xuan Wang, Xiao-Mei Luo, Lu-Jia Zhong, Tian-Tian Feng and Da-Gang Zhou

Catalysts 2025, 15(9), 867; https://doi.org/10.3390/catal15090867 - 9 Sep 2025

Viewed by 288

Abstract

The mechanism of the electrophilic addition between phenylacetylene and N-heterocyclic carbene borane (NHC–borane), initiated by di-tert-butyl peroxide (DTBP), was elucidated at the M06-2X-D3/ma-def2-TZVP level to yield the Z-configured product. The computational results show that DTBP undergoes homolysis to generate two t-BuO· radicals; [...] Read more.

The mechanism of the electrophilic addition between phenylacetylene and N-heterocyclic carbene borane (NHC–borane), initiated by di-tert-butyl peroxide (DTBP), was elucidated at the M06-2X-D3/ma-def2-TZVP level to yield the Z-configured product. The computational results show that DTBP undergoes homolysis to generate two t-BuO· radicals; subsequently, it undergoes an H-shift reaction with N-heterocyclic carbene borane to form the N-heterocyclic carbene boron radical. Then, it is added to phenylacetylene to obtain the product radical intermediate. Finally, the product is yielded via an H-shift reaction. Meanwhile, this paper also explores the formation pathways of relevant byproducts. Structural analysis of the reaction reveals that weak interactions have a significant impact on the selectivity of the Z-configuration of the product. In addition, electron spin density contour maps are used to explain the electron distribution and reaction sites during the reaction process. This paper will provide relevant theoretical support for this type of addition reaction. Full article

(This article belongs to the Section Computational Catalysis)

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18 pages, 946 KB

Open AccessFeature PaperArticle

Dual-Function Bare Copper Oxide (Photo)Catalysts for Selective Phenol Production via Benzene Hydroxylation and Low-Temperature Hydrogen Generation from Formic Acid

by Antonietta Mancuso, Matteo Diglio, Salvatore Impemba, Vincenzo Venditto, Vincenzo Vaiano, Antonio Buonerba and Olga Sacco

Catalysts 2025, 15(9), 866; https://doi.org/10.3390/catal15090866 - 9 Sep 2025

Viewed by 367

Abstract

In this work, bare copper oxide-based catalysts were synthesized and evaluated for their dual (photo)catalytic activity in two model reactions: hydrogen generation via formic acid decomposition (FAD) and the photocatalytic hydroxylation of benzene to phenol. Catalysts were prepared from copper nitrate and copper [...] Read more.

In this work, bare copper oxide-based catalysts were synthesized and evaluated for their dual (photo)catalytic activity in two model reactions: hydrogen generation via formic acid decomposition (FAD) and the photocatalytic hydroxylation of benzene to phenol. Catalysts were prepared from copper nitrate and copper acetate precursors and calcined for either 10 min or 2 h. Their structural and surface properties were characterized by wide-angle X-ray diffraction (WAXD), Raman spectroscopy, and BET surface area analysis. FAD was conducted under mild thermal conditions and monitored via ¹H NMR spectroscopy. At the same time, benzene hydroxylation was performed under UV irradiation and analyzed by gas chromatography (GC) and high-performance liquid chromatography (HPLC). All synthesized catalysts outperformed commercial CuO in the selective oxidation of benzene. The nitrate-derived sample calcined for 10 min (NCuO 10 min) achieved the best performance, with a phenol yield of ~10% and a selectivity of up to 19%, attributed to improved surface properties and the presence of Cu(I) domains, as indicated by Raman spectroscopy. For FAD, complete conversion of formic acid was achieved at low temperatures, with selective H₂ and CO₂ evolution and complete suppression of CO, even under short reaction times and low catalyst loadings. These results demonstrate the potential of nitrate-derived CuO catalysts as versatile, dual-function materials for sustainable applications in selective aromatic oxidation and low-temperature hydrogen generation, without the need for noble metals or harsh conditions. Full article

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

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18 pages, 3074 KB

Open AccessArticle

Dual-Function Fe₃O₄-Cu₂O-Ag/GO Nanocomposites: Efficient Photocatalytic Degradation and Ultrasensitive SERS Detection of Methylene Blue and Malachite Green Dyes

by Boya Ma, Yu Wu, Wenshi Zhao, Shengyi Wang, Yuqing Xiao, Yongdan Wang, Jihui Lang, Chongya Ma and Yang Liu

Catalysts 2025, 15(9), 865; https://doi.org/10.3390/catal15090865 - 7 Sep 2025

Viewed by 412

Abstract

The wastewater discharged from the aquaculture and textile industries often contains toxic organic dyes, such as methylene blue (MB) and malachite green (MG), which pose significant risk to public health and ecosystem stability due to their high chemical stability, bioaccumulation potential and resistance [...] Read more.

The wastewater discharged from the aquaculture and textile industries often contains toxic organic dyes, such as methylene blue (MB) and malachite green (MG), which pose significant risk to public health and ecosystem stability due to their high chemical stability, bioaccumulation potential and resistance to degradation. To address these challenges, the development of an integrated system capable of both efficient degradation and highly sensitive detection of organic dyes is essential for ecological restoration and early pollution monitoring. Herein, bifunctional Fe₃O₄-Cu₂O-Ag-GO (FCA 2-GO) nanocomposites (NCs) were developed by depositing Cu₂O, Ag nanocrystals and graphene oxide (GO) onto the surfaces of Fe₃O₄ nanocrystals. This multifunctional material acted as both a photocatalyst and a surface-enhanced Raman scattering (SERS) platform, enabling simultaneous degradation and ultrasensitive detection of organic dyes. Under simulated sunlight irradiation, FCA 2-GO NCs achieved over 98% degradation of both MB and MG within 60 min, driven by the synergistic action of reactive oxygen species (·O₂⁻ and ·OH). The degradation kinetics followed pseudo-first-order behavior, with rate constants of 0.0381 min⁻¹ (MB) and 0.0310 min⁻¹ (MG). Additionally, the FCA 2-GO NCs exhibited exceptional SERS performance, achieving detection limits as low as 10⁻¹² M for both dyes, attributed to electromagnetic–chemical dual-enhancement mechanisms. Practical applicability was demonstrated in soil matrices, showcasing robust linear correlations (R² > 0.95) between SERS signal intensity and dye concentration. This work provides a dual-functional platform that combines efficient environmental remediation with trace-level pollutant monitoring, offering a promising strategy for sustainable wastewater treatment and environmental safety. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Environmental Purification, 2nd Edition)

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16 pages, 2365 KB

Open AccessArticle

Preparation of Pt/xMnO₂-CNTs Catalyst and Its Electrooxidation Performance in Methanol

by Guang Chen, Zhijun Teng, Hanqiao Xu and Hongwei Li

Catalysts 2025, 15(9), 864; https://doi.org/10.3390/catal15090864 - 7 Sep 2025

Viewed by 317

Abstract

In this study, MnO₂-CNTs composite support was prepared by citric acid reduction method, and then, Pt nanoparticles were loaded on the surface by ethylene glycol reduction method to obtain a series of Pt/xMnO₂-CNTs catalysts. Structural characterization (TEM, XRD, HRTEM) [...] Read more.

In this study, MnO₂-CNTs composite support was prepared by citric acid reduction method, and then, Pt nanoparticles were loaded on the surface by ethylene glycol reduction method to obtain a series of Pt/xMnO₂-CNTs catalysts. Structural characterization (TEM, XRD, HRTEM) showed that Pt nanoparticles were uniformly dispersed on the surface of the catalyst with an average particle size of 3.6 nm. Electrochemical tests show that when the content of MnO₂ is 20 wt.%, the Pt/_20wt.%MnO₂-CNTs catalyst has the best methanol oxidation performance, and its mass activity and long-term stability are 4.0 times and 5.41 times that of commercial Pt/C, respectively. The in situ FTIR results showed that MnO₂ promoted the dissociation of water through synergistic effect, generated abundant OH species, accelerated the oxidation of CO intermediates, and inhibited the poisoning of Pt sites. In this study, it is clear that the excellent performance of Pt/xMnO₂-CNTs is due to multiple synergistic effects. Modified carbon nanotubes facilitate proton conduction, Pt nanoparticles effectively activate methanol, and MnO₂ modulates reaction intermediates via its bifunctional mechanism. This comprehensive mechanism understanding provides a theoretical basis for the design of high-performance catalysts for direct methanol fuel cells. Full article

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33 pages, 2728 KB

Open AccessFeature PaperReview

Advances in Chitosanase Research: From Structure and Function to Green Biocatalytic Production of Chitooligosaccharides

by Oanh Thi Kim Nguyen, Parushi Nargotra, Po-Ting Chen, Chwen-Jen Shieh, Yung-Chuan Liu and Chia-Hung Kuo

Catalysts 2025, 15(9), 863; https://doi.org/10.3390/catal15090863 - 6 Sep 2025

Viewed by 369

Abstract

Chitosanases are glycoside hydrolases (GHs) that catalyze the endo- or exo-type cleavage of β-1,4-glycosidic linkages in chitosan, enabling the selective production of chitooligosaccharides (COSs) with well-defined structures and diverse bioactivities. Owing to their substrate specificity and environmentally friendly catalytic action, chitosanases have garnered [...] Read more.

Chitosanases are glycoside hydrolases (GHs) that catalyze the endo- or exo-type cleavage of β-1,4-glycosidic linkages in chitosan, enabling the selective production of chitooligosaccharides (COSs) with well-defined structures and diverse bioactivities. Owing to their substrate specificity and environmentally friendly catalytic action, chitosanases have garnered increasing attention as sustainable biocatalysts for COS production, with broad application potential in agriculture, food, medicine, and cosmetics. This review provides a comprehensive overview of recent advances in chitosanase research, focusing on the catalytic mechanisms and structure–function relationships that govern substrate selectivity and functional divergence across different GH families. Microbial diversity and heterologous expression systems for chitosanase production are discussed in parallel with biochemical characterization to support the rational selection of enzymes for specific biotechnological applications. Advances in protein engineering and computational approaches are highlighted as strategies to improve catalytic efficiency, substrate range, and stability. In addition, bioprocess optimization is addressed, with emphasis on fermentation using low-cost substrates and the application of immobilized enzymes and nano-biocatalyst systems for green and efficient COS production. Summarizing and discussing previous findings are essential to support future research and facilitate the development of next-generation chitosanases for sustainable industrial use. Full article

(This article belongs to the Special Issue Exclusive Papers of the Editorial Board Members (EBMs) in the Section "Biocatalysis")

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27 pages, 7542 KB

Open AccessFeature PaperArticle

Coke Characterization and Re-Activation Energy Dynamics of Spent FCC Catalyst in the Catalytic Pyrolysis of Polyolefins

by Hussam A. Bahlouli, Rasha Alghamdi and George Manos

Catalysts 2025, 15(9), 862; https://doi.org/10.3390/catal15090862 - 6 Sep 2025

Viewed by 474

Abstract

Chemical recycling via catalytic pyrolysis is constrained by coke deposition and costly catalyst make-up. We investigate polypropylene (PP) and low-density polyethylene (LDPE) conversion over a spent FCC equilibrium catalyst (AXL) and, critically, quantify the re-activation energy landscape of the resulting coke. Using a [...] Read more.

Chemical recycling via catalytic pyrolysis is constrained by coke deposition and costly catalyst make-up. We investigate polypropylene (PP) and low-density polyethylene (LDPE) conversion over a spent FCC equilibrium catalyst (AXL) and, critically, quantify the re-activation energy landscape of the resulting coke. Using a semi-batch reactor (350 °C) and thermogravimetric analysis to 1100 °C combined with the Ozawa–Flynn–Wall method, we distinguish soft and hard coke under inert, oxidative, and sequential N₂ to air regimes. LDPE yields mainly gas (70.7 wt%) with 5.5 wt% coke, whereas PP favors liquids (47.1 wt%) with 3.4 wt% coke. LDPE-derived coke is softer (71% of total; E_A = 170 kJ mol⁻¹ soft) than PP coke (60% soft; E_A = 166 kJ mol⁻¹), evidencing a more refractory PP residue. Oxygen lowers E_A to ~155 kJ mol⁻¹ for both polymers. We introduce a simple TGA-based “softness ratio” to guide regeneration severity and show that a refinery-waste FCC catalyst delivers selective plastic-to-fuel conversion while enabling energy-aware regeneration protocols. The framework directly supports scale-up by linking polymer structure, coke quality, and atmosphere-dependent re-activation energetics. Full article

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

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17 pages, 3449 KB

Open AccessFeature PaperArticle

Structure of Cu, Ni, and CuNi Bimetallic Small Clusters Incorporated in g-C₃N₄: A DFT Study

by Agnieszka Drzewiecka-Matuszek, Priti Sharma and Dorota Rutkowska-Zbik

Catalysts 2025, 15(9), 861; https://doi.org/10.3390/catal15090861 - 6 Sep 2025

Viewed by 447

Abstract

Graphitic carbon nitride is recognized as a very promising support structure to anchor single atoms and small, sub-nanometric metal clusters, with vast applications in catalysis. In the current manuscript, we aim to study the geometry and electronic structures of the small, sub-nanometric monometallic [...] Read more.

Graphitic carbon nitride is recognized as a very promising support structure to anchor single atoms and small, sub-nanometric metal clusters, with vast applications in catalysis. In the current manuscript, we aim to study the geometry and electronic structures of the small, sub-nanometric monometallic (copper or nickel) and bimetallic (copper–nickel) clusters anchored to the graphitic carbon nitride. Our Density Functional Theory (DFT) study reveals that Cu and Ni, when in the form of isolated single atoms, lie in the plane of the support. Once the atoms agglomerate and form small clusters, they tend to bind above the carbon nitride (C₃N₄) plane. The nickel atoms form shorter bonds with the support than the copper atoms do, which is reflected by the binding energies. Atoms directly bound to the support become oxidized, forming electrophilic sites at the surface. The computed negative metal–support binding energies mean that the investigated Cu/Ni-C₃N₄ composites are stable, and the metal species will not easily leach from the support. Full article

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

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31 pages, 2847 KB

Open AccessArticle

Effects of Crystallinity and Pore Architecture of Titanium Silicalites on α-Pinene Oxidation

by Jadwiga Grzeszczak, Agnieszka Wróblewska and Beata Michalkiewicz

Catalysts 2025, 15(9), 860; https://doi.org/10.3390/catal15090860 - 5 Sep 2025

Viewed by 463

Abstract

Titanium silicalite-1 (TS-1) is an effective catalyst, but its limited pore size restricts the access of bulky substrates such as α-pinene. In our previous studies, a TS-1 catalyst with a Si/Ti molar ratio of 20:1 demonstrated high activity in α-pinene oxidation but suffered [...] Read more.

Titanium silicalite-1 (TS-1) is an effective catalyst, but its limited pore size restricts the access of bulky substrates such as α-pinene. In our previous studies, a TS-1 catalyst with a Si/Ti molar ratio of 20:1 demonstrated high activity in α-pinene oxidation but suffered from diffusion limitations. To overcome this drawback, four new titanium silicate catalysts were synthesized using the reference TS-1 as the parent material (TS-1 catalyst with the Si/Ti molar ratio of 20:1). MTS-1_1 and MTS-1_2 were prepared via a co-templating method, while HTS-1_1 and HTS-1_2 were obtained through post-synthetic recrystallization using triethylamine (method I) or sulfuric acid followed by triethylamine (method II). All catalysts were characterized by UV–Vis, FTIR, XRD, SEM, EDXRF, and nitrogen sorption, and their activity was tested in solvent-free oxidation of α-pinene using molecular oxygen. The influence of temperature, catalyst content, and reaction time on the conversion of α-pinene and the selectivities of the main products was investigated. All modified materials exhibited higher catalytic activity than the reference TS-1 material. HTS-1_2 showed the best results, achieving the conversion of α-pinene of 21 mol% and the selectivity of transformation to α-pinene oxide of 35 mol%. Verbenol and verbenone were also formed as valuable oxygenated products. The developed catalysts enable a green and efficient transformation of renewable α-pinene into high-value derivatives. Full article

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

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15 pages, 3221 KB

Open AccessFeature PaperArticle

Investigation on Pt-WO₃ Catalytic Interface for the Hydrodeoxygenation of Anisole

by Wanru Yan, Jiating Li, Nan Ma, Zemin An, Yuanjie Xu, Lizhi Wu, Li Tan and Yu Tang

Catalysts 2025, 15(9), 859; https://doi.org/10.3390/catal15090859 - 5 Sep 2025

Viewed by 453

Abstract

As a model compound for lignin derivatives, anisole and its conversion are crucial for the upgrading of biomass resources. Anisole molecule contains a characteristic aryl ether bond (C_aryl-O-CH₃); therefore, the selective cleavage of the C-O bond to efficiently produce [...] Read more.

As a model compound for lignin derivatives, anisole and its conversion are crucial for the upgrading of biomass resources. Anisole molecule contains a characteristic aryl ether bond (C_aryl-O-CH₃); therefore, the selective cleavage of the C-O bond to efficiently produce high-value chemicals poses a significant challenge. Constructing bimetallic synergistic active sites through tuning the metal-support interface is considered an effective strategy. In this work, the WO₃-promoted Pt/SiO₂ catalysts were investigated to enhance the performance of anisole hydrodeoxygenation (HDO) to hydrocarbons. Experimental results demonstrate that WO₃ significantly promotes HDO selectivity, increasing from 37.8% to 86.8% at 250 °C. Moreover, moderate doping improves low-temperature (<250 °C) HDO activity, confirming the presence of synergistic effects. In contrast, excessive WO₃ suppresses anisole conversion. Characterization results reveal that WO₃ stabilizes metallic Pt and facilitates H₂ dissociation. Concurrently, strong hydrogen spillover between Pt and WO₃ promotes oxygen vacancy formation on WO₃. This transforms disordered adsorption of anisole on SiO₂ into directed adsorption of the anisole’s oxygen species onto WO₃. This work achieves high anisole HDO selectivity through the Pt-WO₃ interface tuning, offering novel insights for efficient lignin conversion. 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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15 pages, 1737 KB

Open AccessArticle

Comparative Thermal and Supramolecular Hydrothermal Synthesis of g-C₃N₄ Toward Efficient Photocatalytic Degradation of Gallic Acid

by Fernando Cantor Pérez, Julia Liliana Rodríguez Santillán, Ricardo Santillán Peréz, Iliana Fuentes Camargo, Issis C. Romero Ibarra, Jesús I. Guzmán Castañeda, Jorge L. Vazquez-Arce, Hugo Tiznado and Hugo Martínez Gutiérrez

Catalysts 2025, 15(9), 858; https://doi.org/10.3390/catal15090858 - 5 Sep 2025

Viewed by 504

Abstract

Gallic acid (GA), a polyphenol extensively used in the food, wine, and pharmaceutical industries, is known for its inhibitory effects on soil microbial activity. Photocatalytic degradation offers an environmentally friendly solution for GA removal from water. In this work, graphitic carbon nitride (g-C [...] Read more.

Gallic acid (GA), a polyphenol extensively used in the food, wine, and pharmaceutical industries, is known for its inhibitory effects on soil microbial activity. Photocatalytic degradation offers an environmentally friendly solution for GA removal from water. In this work, graphitic carbon nitride (g-C₃N₄) photocatalysts were synthesized by two methods: thermal exfoliation (CN-E) and supramolecular assembly via hydrothermal processing (HCN-II). Structural analyses by XRD, FTIR, and XPS confirmed the formation of the g-C₃N₄ framework, while SEM revealed that CN-E consisted of folded and curled nanosheets, whereas HCN-II displayed a polyhedral–nanosheet hybrid architecture with internal channels. Both materials achieved approximately 80% GA degradation within 180 min under visible-light irradiation, yet HCN-II exhibited a superior apparent rate constant (k = 0.01156 min⁻¹) compared with CN-E. Radical trapping experiments demonstrated that O₂•⁻ and h⁺ were the primary reactive oxygen species involved, with OH• making a minor contribution. The enhanced performance of HCN-II is attributed to its higher surface area, improved light harvesting, and efficient charge separation derived from supramolecular assembly. These findings highlight the potential of engineered g-C₃N₄ nanostructures as efficient, metal-free photocatalysts for the degradation of recalcitrant organic pollutants in water treatment applications. Full article

(This article belongs to the Special Issue Environmentally Friendly Catalytic Nanomaterials for Advanced Oxidation and Reduction Technology)

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11 pages, 2644 KB

Open AccessArticle

Density Functional Theory Study in Photocatalytic Water Splitting via Covalent Triazine Frameworks Functioned by Benzothiophene Sulfone

by Li Chen, Shouxi Yu, Xin Wang and Zhongliao Wang

Catalysts 2025, 15(9), 857; https://doi.org/10.3390/catal15090857 - 4 Sep 2025

Viewed by 510

Abstract

Photocatalytic overall water splitting (PWS) offers a green, economical, and sustainable pathway for hydrogen production. However, the efficiency is still hindered by severe charge recombination in catalysts, high energy barriers for water oxidation, and sluggish reaction kinetics. Therefore, it is crucial to address [...] Read more.

Photocatalytic overall water splitting (PWS) offers a green, economical, and sustainable pathway for hydrogen production. However, the efficiency is still hindered by severe charge recombination in catalysts, high energy barriers for water oxidation, and sluggish reaction kinetics. Therefore, it is crucial to address these challenges by enhancing charge separation efficiency, accelerating reaction kinetics, and lowering PWS energy barriers. In this work, we constructed donor–acceptor covalent triazine-based organic frameworks (CTFs), such as CTF-BP, CTF-DBT, and CTF-DBTS, using biphenyl (BP), benzothiophene (DBT), and benzothiophene sulfone (DBTS) as basic units, respectively. DFT calculations revealed that all three CTFs exhibit comparable bandgaps with strong visible-light absorption. Notably, strong dipole moments between donor and acceptor units were observed within these frameworks, effectively promoting in-plane charge separation. DBT and DBTS derivatives generated stronger dipole moments compared to biphenyl. Furthermore, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) pathway analyses demonstrated that CTF-DBTS substantially reduces energy barriers for both half-reactions relative to CTF-DBT and CTF-BP, exhibiting the most promising potential for PWS. This work provides a reference for the application of DBTS-incorporated COFs in PWS systems. Full article

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

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20 pages, 5034 KB

Open AccessReview

Copper Active Sites in Metal–Organic Frameworks Advance CO₂ Adsorption and Photocatalytic Conversion

by Enhui Jiang, Yan Yan and Yongsheng Yan

Catalysts 2025, 15(9), 856; https://doi.org/10.3390/catal15090856 - 4 Sep 2025

Viewed by 621

Abstract

The photocatalytic reduction of CO₂ into high-value chemicals utilizing solar energy represents a sustainable approach to mitigating greenhouse gas emissions and advancing renewable chemical production. Recently, copper-based metal–organic frameworks (Cu-MOFs) have been extensively researched for their potential in photocatalytic CO₂ reduction, [...] Read more.

The photocatalytic reduction of CO₂ into high-value chemicals utilizing solar energy represents a sustainable approach to mitigating greenhouse gas emissions and advancing renewable chemical production. Recently, copper-based metal–organic frameworks (Cu-MOFs) have been extensively researched for their potential in photocatalytic CO₂ reduction, due to their high affinity for capturing CO₂, the presence of unsaturated Cu sites, and their advantageous photochemical properties. In this review, we first provide an overview of Cu active sites in the secondary building units (SBUs) of MOFs, focusing on their selective adsorption of CO₂ gas and analyzing the mechanisms of the multi-electron transfer processes involved in Cu-based photocatalytic reduction of CO₂. Ultimately, this article outlines the existing obstacles and suggests potential avenues for future research. Full article

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

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3 pages, 132 KB

Open AccessEditorial

Advanced Catalytic Processes for Wastewater Treatment

by Dionissios Mantzavinos, Athanasia Petala and Olga S. Arvaniti

Catalysts 2025, 15(9), 855; https://doi.org/10.3390/catal15090855 - 4 Sep 2025

Viewed by 369

Abstract

The increasing demand for clean water, along with the persistent release of organic pollutants such as pharmaceuticals, pesticides, and dyes into aquatic environments, underscores the urgent need for efficient wastewater treatment technologies [...] Full article

(This article belongs to the Special Issue Advanced Catalytic Processes for Wastewater Treatment)

13 pages, 4544 KB

Open AccessArticle

Anodic Catalytic Oxidation of Sulfamethoxazole: Efficiency and Mechanism on Co₃O₄ Nanowire Self-Assembled CoFe₂O₄ Nanosheet Heterojunction

by Han Cui, Qiwei Zhang and Shan Qiu

Catalysts 2025, 15(9), 854; https://doi.org/10.3390/catal15090854 - 4 Sep 2025

Viewed by 465

Abstract

By modulating the mass ratio of hydrothermal agents to cobalt/iron precursors, Co₃O₄ nanowires were successfully integrated into spinel-type Co/Fe@NF, forming a heterojunction anode for alkaline water electrolysis (AWE) hydrogen production. This Co₃O₄ nanowire-assembled CoFe₂O₄ [...] Read more.

By modulating the mass ratio of hydrothermal agents to cobalt/iron precursors, Co₃O₄ nanowires were successfully integrated into spinel-type Co/Fe@NF, forming a heterojunction anode for alkaline water electrolysis (AWE) hydrogen production. This Co₃O₄ nanowire-assembled CoFe₂O₄ nanosheet anode (Co/Fe(5:1)@NF) exhibits exceptional electrochemical oxygen evolution reaction (OER) performance, requiring only 221 mV overpotential to achieve 10 mA cm⁻². Sulfamethoxazole (SMX) was employed as a model pollutant to investigate the anode sacrificial material; it achieved approximately 95% SMX degradation efficiency, reducing the OER potential of 50 mV/10 mA cm⁻². SMX oxidation coupled with Co/Fe heterojunction structure partially substitutes the OER. Co/Fe heterojunction generates an internal magnetic field, which induces the formation of novel active species within the system. ·O₂⁻ is the newly formed active oxygen species, which enhanced the proportion of indirect SMX oxidation. Quantitative analysis reveals that superoxide radical-mediated indirect oxidation of SMX accounts for approximately 38.5%, Fe(VI) for 9.4%, other active species for 6.1%, and direct oxidation for 46.0%. The nanowire–nanosheet assembly stabilizes a high-spin configuration on the catalyst surface, redirecting oxygen intermediate pathways toward triplet oxygen (³O₂) generation. Subsequent electron transfer from nanowire tips facilitates rapid ³O₂ reduction, forming superoxide radicals (·O₂⁻). This study effectively driven by indirect oxidation, with cathodic hydrogen production, providing a novel strategy for utilizing renewable electricity and reducing OER while offering insights into the design of Co/Fe-based catalyst. Full article

(This article belongs to the Section Electrocatalysis)

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19 pages, 11323 KB

Open AccessArticle

Hydrogen Production via Dry Reforming of Methane Using a Strontium Promoter over MgO-Supported Ni Catalyst: A Cost-Effective Catalyst System

by Abdulaziz S. Bentalib, Amal BaQais, Fekri Abdulraqeb Ahmed Ali, Kirankumar Jivabhai Chaudhary, Abdulaziz A. M. Abahussain, Abdulrahman Bin Jumah, Mohammed O. Bayazed, Alaaddin M. M. Saeed, Rawesh Kumar and Ahmed S. Al-Fatesh

Catalysts 2025, 15(9), 853; https://doi.org/10.3390/catal15090853 - 4 Sep 2025

Viewed by 534

Abstract

In the race for industrialization and urbanization, the concentration of greenhouse gases like CO₂ and CH₄ is growing rapidly and ultimately resulting in global warming. An Ni-based catalyst over MgO support (Ni/MgO) offers a catalytic method for the conversion of these [...] Read more.

In the race for industrialization and urbanization, the concentration of greenhouse gases like CO₂ and CH₄ is growing rapidly and ultimately resulting in global warming. An Ni-based catalyst over MgO support (Ni/MgO) offers a catalytic method for the conversion of these gases into hydrogen and carbon monoxide through the dry reforming of methane (DRM) reaction. In the current research work, 1–4 wt% strontium is investigated as a cheap promoter over a 5Ni/MgO catalyst to modify the reducibility and basicity for the goal of excelling the H₂ yield and H₂/CO ratio through the DRM reaction. The fine catalytic activities’ correlations with characterization results (like X-ray diffraction, surface area porosity, photoelectron–Raman–infrared spectroscopy, and temperature-programmed reduction/desorption (TPR/TPD)) are established. The 5Ni/MgO catalyst with a 3 wt.% Sr loading attained the highest concentration of stable active sites and the maximum population of very strong basic sites. 5Ni3Sr/MgO surpassed 53% H₂ yield (H₂/CO ~0.8) at 700 °C and 85% H₂ yield (H₂/CO ratio ~0.9) at 800 °C. These outcomes demonstrate the catalyst’s effectiveness and affordability. Higher Sr loading (>3 wt%) resulted in a weaker metal–support contact, the production of free NiO, and a lower level of catalytic activity for the DRM reaction. The practical and cheap 5Ni3Sr/MgO catalyst is scalable in industries to achieve hydrogen energy goals while mitigating greenhouse gas concentrations. 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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13 pages, 1743 KB

Open AccessArticle

Pd Nanoparticles Confined by Nitrogen-Doped Carbon Architecture Derived from Zeolitic Imidazolate Frameworks for Remarkable Hydrogen Evolution from Formic Acid Dehydrogenation

by Jun Wang, Haotian Qin, Mingquan Liu, Siyuang Tang, Linlin Xu, Xiang Ding and Fuzhan Song

Catalysts 2025, 15(9), 852; https://doi.org/10.3390/catal15090852 - 4 Sep 2025

Viewed by 511

Abstract

The development of heterogeneous nanocatalysts with high performance is essential for improving hydrogen production through formic acid dehydrogenation, but challenging. Herein, highly dispersed Pd nanoparticles (NPs) were successfully immobilized on porous nitrogen-doped carbon cages (PNCCs) derived from zeolitic imidazole frameworks. By virtue of [...] Read more.

The development of heterogeneous nanocatalysts with high performance is essential for improving hydrogen production through formic acid dehydrogenation, but challenging. Herein, highly dispersed Pd nanoparticles (NPs) were successfully immobilized on porous nitrogen-doped carbon cages (PNCCs) derived from zeolitic imidazole frameworks. By virtue of the synergistic effect, the optimized Pd/PNCC nanocatalytic systems exhibit an excellent catalytic kinetics toward catalyzing FA dehydrogenation with a turnover frequency (TOF) value as high as 3174 h⁻¹ at 323 K, which is 59 times relative to that of Pd nanoparticles. The exceptional activity may be ascribed to the PNCC solid support may induce a strong electronic metal–support interaction to optimize the electron configuration of Pd active sites and accelerate the kinetics of O-H bond cleavage, resulting in an enhanced catalytic performance toward FA dehydrogenation. This work will supply a novel strategy for the development of supported nanocatalysts with high performance for tremendous catalytic applications in the future. 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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