Catalysts

11 pages, 1979 KiB

Open AccessFeature PaperArticle

In Situ Synthesis of Hierarchical Carbon-Encapsulated Pd Nanoparticles as an Efficient Semi-Hydrogenation Catalyst

by Weijie Kong, Wenhui Zhang, Yiming Wang, Xin Chen, Yongjian Ai, Zenan Hu and Hong-Bin Sun

Catalysts 2025, 15(3), 295; https://doi.org/10.3390/catal15030295 - 20 Mar 2025

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The process of directly using atmospheric H₂ for the catalytic semi-hydrogenation of alkynes to alkenes has significant applications in the polyolefin industry. Herein, we report a facile approach to synthesize a hierarchical carbon-encapsulated Pd catalyst for the highly selective semi-hydrogenation of nitrophenylacetylene. [...] Read more.

The process of directly using atmospheric H₂ for the catalytic semi-hydrogenation of alkynes to alkenes has significant applications in the polyolefin industry. Herein, we report a facile approach to synthesize a hierarchical carbon-encapsulated Pd catalyst for the highly selective semi-hydrogenation of nitrophenylacetylene. The catalyst featured a structure of (Pd@NG)/(Pd@C), which demonstrated that an oligo-layer of nitrogen-doped graphene (NG)-encapsulated Pd particles are supported on the carbon matrix, semi-embedded by another type of Pd particle. The catalyst, named Pd@NC, achieved 99% selectivity for nitrostyrene at 97% nitrophenylacetylene conversion and demonstrated an excellent stability. A good selectivity arose from the bridging effect of hierarchical porous carbon, where hydrogen activation and alkyne hemihydrogenation took place on palladium particles and NG, respectively. The NG layer provided excellent protection against the over-hydrogenation of the reaction. Full article

(This article belongs to the Special Issue Catalyst Immobilization)

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16 pages, 3412 KiB

Open AccessFeature PaperReview

The Application of Zeolites in the Selective Synthesis of Methylamine: A Review

by Keyan Jin, Yuxin Yan, Junyao Pan, Jing-Yao Liu and Wenfu Yan

Catalysts 2025, 15(3), 294; https://doi.org/10.3390/catal15030294 - 20 Mar 2025

Viewed by 367

Abstract

Methylamines, including monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA), are essential industrial intermediates. However, traditional catalysts suffer from poor product selectivity and are being phased out due to shifting market demands. Zeolites have emerged as promising alternatives due to their high activity and [...] Read more.

Methylamines, including monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA), are essential industrial intermediates. However, traditional catalysts suffer from poor product selectivity and are being phased out due to shifting market demands. Zeolites have emerged as promising alternatives due to their high activity and superior selectivity. Large- and medium-pore zeolites require modifications to enhance MMA- and DMA-selectivity by reducing pore size, whereas small-pore zeolites inherently exhibit high selectivity for MMA and DMA without modification. However, their high production costs have hindered large-scale commercialization. Research efforts are now focused on developing cost-effective catalysts to shift methylamine synthesis from equilibrium-driven (balancing) to selective (unbalancing) processes. This review explores the performance of zeolite-based catalysts in methylamine synthesis, highlighting key factors influencing selectivity. Additionally, it examines the challenges associated with small-pore zeolites and discusses strategies to enhance their application. Full article

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

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31 pages, 5746 KiB

Open AccessFeature PaperReview

Development of Electrochemical Water Splitting with Highly Active Nanostructured NiFe Layered Double Hydroxide Catalysts: A Comprehensive Review

by Aviraj M. Teli, Sagar M. Mane, Sonali A. Beknalkar, Rajneesh Kumar Mishra, Wookhee Jeon and Jae Cheol Shin

Catalysts 2025, 15(3), 293; https://doi.org/10.3390/catal15030293 - 20 Mar 2025

Viewed by 712

Abstract

Electrochemical water splitting is a feasible and effective method for attaining hydrogen, offering a mechanism for renewable energy solutions to combat the world’s energy crises due to the scarcity of fossil fuels. Evidently, the viability and stability of the electrocatalysts are fundamental to [...] Read more.

Electrochemical water splitting is a feasible and effective method for attaining hydrogen, offering a mechanism for renewable energy solutions to combat the world’s energy crises due to the scarcity of fossil fuels. Evidently, the viability and stability of the electrocatalysts are fundamental to the electrochemical water-splitting process. However, the net efficiency of this process is noticeably hindered by the kinetic drawbacks related to the OER. Hence, NiFe LDH has been widely used as a highly efficient OER and HER catalyst material due to its unique nanostructure, tunable composition, and favorable electronic structure. This review offers a systematic analysis of the latest progress in the fabrication of functional NiFe LDH catalysts and associated fabrication strategies, structure optimizations, and performance improvements. Special emphasis is given to understanding the role of nanostructure engineering in increasing active site accessibility, enhancing the effectiveness of subsequent electron transfer, and boosting the intrinsic catalytic activity for HER and OER. Moreover, we discuss the influence of doping, defects, and the formation of heterostructures with other materials on the OER and HER activities of NiFe LDHs. Additional accounts of basic structures and the OER and HER catalytic activities are provided, along with an enhanced theoretical understanding based on DFT studies on the NiFe LDH. Moreover, the limitations and potential developments of the work focus on the need for existing synthesis approaches, the stability of the NiFe LDH catalysts, and their insertion into working electrochemical processes. This review is a comprehensive analysis of the current state of research and developments in the use of NiFe LDH catalysts for the electrochemical water-splitting process to foster improved development of sustainable hydrogen sources in the future. Full article

(This article belongs to the Special Issue Nanostructured Materials for Electrocatalytic Applications)

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22 pages, 8771 KiB

Open AccessArticle

Controlled Synthesis of Nickel Phosphides in Hollow N, P Co-Doped Carbon: In Situ Transition to (Oxy)hydroxide Phases During Oxygen Evolution Reaction

by David Ríos-Ruiz, Pablo Arévalo-Cid, Jesús Cebollada, Verónica Celorrio, Miran Čeh, Sandra Drev and María Victoria Martínez-Huerta

Catalysts 2025, 15(3), 292; https://doi.org/10.3390/catal15030292 - 20 Mar 2025

Viewed by 573

Abstract

Developing sustainable and efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing energy storage technologies. This study explored the dual role of phosphorus as a dopant in carbon matrices and a key component in nickel phosphides (Ni₂P and [...] Read more.

Developing sustainable and efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing energy storage technologies. This study explored the dual role of phosphorus as a dopant in carbon matrices and a key component in nickel phosphides (Ni₂P and Ni₁₂P₅), synthesized using dopamine (PDA) and ammonium phosphate as eco-friendly precursors. The phase formation of nickel phosphides was found to be highly dependent on the P/PDA ratio (0.15, 0.3, 0.6, and 0.9), allowing for the selective synthesis of Ni₂P or Ni₁₂P₅. Operando Raman spectroscopy revealed that both phases undergo surface transformation into nickel (oxy)hydroxide species under OER conditions, yet Ni₂P-based catalysts demonstrated superior activity and long-term stability. This enhancement is attributed to efficient electron transfer at the dynamic Ni₂P/NiOOH interface. Additionally, hollow nanostructures formed at intermediate P/PDA ratios (≤0.3) via the Kirkendall effect and Ostwald ripening contributed to an increased specific surface area and micropore volume, further improving the catalytic performance. Electrochemical impedance spectroscopy confirmed reduced interfacial resistance and enhanced charge transport. These findings offer new insights into the rational design of high-performance electrocatalysts and propose a green, tunable synthesis approach for advanced energy conversion applications. Full article

(This article belongs to the Special Issue Recent Advances in Electrocatalysis and Future Perspective)

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17 pages, 4600 KiB

Open AccessArticle

Catalytic Reduction of SO₂ with CO over LaCoO₃ Perovskites Catalysts: Effect of Fe Doping and Pre-Sulfurization

by Liang Yao, Hao Wang, Shuangde Li and Yunfa Chen

Catalysts 2025, 15(3), 291; https://doi.org/10.3390/catal15030291 - 19 Mar 2025

Viewed by 315

Abstract

SO₂ emissions are a major source of air pollution, and the catalytic reduction of SO₂ to elemental sulfur by CO represents a promising solution. This study investigates the effects of Fe doping and pre-sulfurization on the catalytic performance of LaCoO₃ perovskite [...] Read more.

SO₂ emissions are a major source of air pollution, and the catalytic reduction of SO₂ to elemental sulfur by CO represents a promising solution. This study investigates the effects of Fe doping and pre-sulfurization on the catalytic performance of LaCoO₃ perovskite catalysts. A series of Fe-doped LaCoO₃ perovskites were synthesized via the sol–gel method and evaluated for the catalytic reduction of SO₂ by CO. The results showed that LaCo_0.8Fe_0.2O₃ exhibited the highest catalytic performance, achieving 84.0% SO₂ conversion at 500 °C. The oxygen-free sulfurization (OFS) treatment compared with oxygen-assisted sulfurization (OAS) treatment significantly enhanced the activity, reaching a SO₂ conversion of 95.9% from 80.0% at 450 °C with the lower byproduct generation. Characterization analyses demonstrated that the OFS treatment facilitated the formation of active sulfur species and oxygen vacancies on the catalyst surface while also enhancing the adsorption capacity of the catalyst for the reactant gases. These factors were identified as key contributors to the improved catalytic performance, driven by the combination of redox and carbonyl sulfide (COS) intermediate mechanism. The findings suggest that the OFS treatment is an effective strategy to improve the catalytic reduction of SO₂ by CO, offering a more environmentally friendly solution for SO₂ emission control through resource utilization. Full article

(This article belongs to the Special Issue Advances in Catalysis for a Sustainable Future)

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17 pages, 4424 KiB

Open AccessArticle

Synthesis of MnO₂ with Different Crystal Phases via Adjusting pH for Ozone Decomposition Under Various Humidity Conditions and Monolithic Catalyst Development

by Haoran Bian, Zukun Xie and Qi Zhang

Catalysts 2025, 15(3), 290; https://doi.org/10.3390/catal15030290 - 19 Mar 2025

Viewed by 311

Abstract

MnO₂ catalysts are recognized as highly efficient materials for ozone decomposition at room temperature. However, the conventional preparation methods, such as the hydrothermal method, typically require critical conditions (100–200 °C for 6–48 h). Moreover, the prepared catalysts are almost powders, which makes [...] Read more.

MnO₂ catalysts are recognized as highly efficient materials for ozone decomposition at room temperature. However, the conventional preparation methods, such as the hydrothermal method, typically require critical conditions (100–200 °C for 6–48 h). Moreover, the prepared catalysts are almost powders, which makes them difficult to apply as monolithic catalysts. In this work, a simple pH-adjusted method was developed to in situ prepare MnO₂ with different crystal phases (α, amorphous, and δ) under ambient conditions. XRD analysis revealed that decreasing the pH from 13 to 3 induced a gradual phase transformation from δ-MnO₂ to amorphous MnO₂, while the α-phase appeared at pH = 1.5. The combination of XPS and O₂-TPD results shows that amorphous MnO₂ exhibited the lowest average oxidation state (AOS) and highest oxygen vacancy concentration. The optimized amorphous MnO₂ catalyst (Cat. 2) achieved the highest ozone removal efficiency of 98% with a high relative humidity of 90%. Furthermore, in situ DRIFTS experiments further demonstrated that the prepared Cat. 2 maintained minimal OH accumulation under humid conditions, confirming its excellent water resistance. Finally, the preparation method of amorphous MnO₂ was effectively applied to cordierite honeycomb carrier (CHC). The a(amorphous)-MnO₂/CHC catalyst module (100 mm × 100 mm × 20 mm) showed stable ozone removal efficiency of 60% during a 60 h evaluation in an air duct (O₃: 400 ± 30 ppb, T: 25 ± 5 °C, gas velocity: 1 m s⁻¹). This study innovatively developed a simple pH-adjusted method to prepare MnO₂ with different crystal phases under ambient conditions and successfully applied it to the cordierite honeycomb carrier for monolithic catalyst development. Full article

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13 pages, 4956 KiB

Open AccessArticle

Investigating the Photocatalytic Properties of Reduced Graphene Oxide-Coated Zirconium Dioxide and Their Impact on Structural and Morphological Features

by Norhan Farghly, M. Abu El-Oyoun, A. Abousehly, Fatemah H. Alkallas, Amira Ben Gouider Trabelsi, E. R. Shaaban and Abdelaziz Mohamed Aboraia

Catalysts 2025, 15(3), 289; https://doi.org/10.3390/catal15030289 - 19 Mar 2025

Viewed by 354

Abstract

Semiconductor photocatalytic technology demonstrates strong potential as a solution to defend environmental systems while converting energy. The photocatalytic behavior of traditional ZrO₂ catalysts suffers a major disadvantage because their activity remains low in visible light applications. XRD together with SEM, as well [...] Read more.

Semiconductor photocatalytic technology demonstrates strong potential as a solution to defend environmental systems while converting energy. The photocatalytic behavior of traditional ZrO₂ catalysts suffers a major disadvantage because their activity remains low in visible light applications. XRD together with SEM, as well as EDX and EIS techniques, were utilized to evaluate the synthetic materials. This study demonstrated that the development of RGO-modified ZrO₂ heterostructures delivered substantial increases in photocatalytic functionality through effective photogenerated charge separation mechanisms. Tests showed the RGO/ZrO₂ heterostructures exhibited outstanding photocatalytic behavior that led to an 80% MB solution breakdown in 120 min while exceeding electrocatalytic parameters in multiple tests. The experimental data from UV–vis spectroscopy combined with electrochemical analysis and radical trapping methods demonstrated that heterostructure improvement resulted from higher light absorption rates and effective active site exposure while providing better electron/hole pair separation. This research establishes S-scheme heterostructures to enable advancements in environmental protection alongside energy conversion technologies. Full article

(This article belongs to the Special Issue Design and Application of Combined Catalysis)

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16 pages, 6061 KiB

Open AccessArticle

Modified Resazurin Ink Testing and the Fluorescence Probe Method for Simple and Rapid Photocatalytic Performance Evaluation

by Kengo Hamada, Daichi Minami, Misa Nishino and Tsuyoshi Ochiai

Catalysts 2025, 15(3), 288; https://doi.org/10.3390/catal15030288 - 19 Mar 2025

Viewed by 432

Abstract

Evaluating the air purification performance of photocatalytic materials typically requires complex gas decomposition tests involving expensive analytical equipment and lengthy testing periods. In this study, photocatalytic performance evaluation methods involving resazurin (Rz) ink and fluorescence probe techniques were investigated as alternatives to conventional [...] Read more.

Evaluating the air purification performance of photocatalytic materials typically requires complex gas decomposition tests involving expensive analytical equipment and lengthy testing periods. In this study, photocatalytic performance evaluation methods involving resazurin (Rz) ink and fluorescence probe techniques were investigated as alternatives to conventional gas decomposition tests. TiO₂ films with varying performance levels were fabricated by controlling TiO₂ slurry concentration and the amount of photocatalyst deposited through spin coating. Photocatalytic performances of the synthesised films were then evaluated using the acetaldehyde decomposition method, Rz ink test, and fluorescence probe method for measuring OH radical generation. The acetaldehyde decomposition rate constants showed high correlation with both the Rz colour change rate in modified-pH ink (R² = 0.91) and the OH radical concentration (R² = 0.98). Conventional Rz ink testing for high-performance materials showed rapid colour changes, indicating its limited applicability. Our modified-pH Rz ink enabled facile analysis by ensuring controlled reactivity. Both the modified Rz ink method, which enables quantitative evaluation within five minutes even for high-performance materials, and the fluorescence probe method are suitable as reliable screening tools for photocatalytic air purification materials. These simplified evaluation methods will aid in developing more efficient photocatalysts and advancing environmental purification technologies. Full article

(This article belongs to the Special Issue TiO₂ Photocatalysts: Design, Optimization and Application)

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19 pages, 2403 KiB

Open AccessReview

A Review Paper on Non-Thermal Plasma Catalysis for CH₄ and CO₂ Reforming into Value Added Chemicals and Fuels

by Subash Mohandoss, Harshini Mohan, Natarajan Balasubramaniyan, Amine Aymen Assadi, Lotfi Khezami and Sivachandiran Loganathan

Catalysts 2025, 15(3), 287; https://doi.org/10.3390/catal15030287 - 19 Mar 2025

Viewed by 629

Abstract

The global reliance on fossil fuels, particularly natural gas, underscores the urgency of developing sustainable methods for methane (CH₄) and carbon dioxide (CO₂) conversion. Methane, which constitutes 95% of natural gas, is a critical feedstock and fuel source. However, [...] Read more.

The global reliance on fossil fuels, particularly natural gas, underscores the urgency of developing sustainable methods for methane (CH₄) and carbon dioxide (CO₂) conversion. Methane, which constitutes 95% of natural gas, is a critical feedstock and fuel source. However, its high bond dissociation energy and volatility pose challenges for large-scale utilization and transport. Current research emphasizes the catalytic and plasma-assisted conversion of CH₄ and CO₂ into value-added products such as methanol, higher hydrocarbons, and organic oxygenates. Advancements in these technologies aim to overcome obstacles such as high operating temperatures, coking, and low product selectivity while addressing methane’s environmental impact, as leakage during extraction and distribution significantly contributes to global warming. Plasma-assisted conversion has emerged as a promising approach, leveraging electron impact processes to generate reactive species that facilitate CH₄ and CO₂ transformation at near-room temperatures. The integration of catalysts within plasma environments enhances reaction pathways, product yields, and selectivity by modifying plasma properties and surface interactions. This review comprehensively discusses the various methods investigated for CH₄ conversion and energy efficiency. We attempt to highlight the recent progress in plasma-assisted catalytic processes for CH₄ and CO₂ valorization, with a focus on the mechanisms of product formation, catalyst modifications, and their impact on plasma discharge characteristics. The insights gained could pave the way for scalable, energy-efficient solutions to produce sustainable fuels and chemicals, thereby contributing to global efforts in carbon cycle fixation and climate change mitigation. Full article

(This article belongs to the Special Issue Plasma Catalysis for Environment and Energy Applications)

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27 pages, 4885 KiB

Open AccessFeature PaperReview

Advances in the Preparation of Carrier-Based Composite Photocatalysts and Their Applications

by Huiqin Wang, Chenlong Yan, Mengyang Xu and Xianghai Song

Catalysts 2025, 15(3), 286; https://doi.org/10.3390/catal15030286 - 19 Mar 2025

Viewed by 329

Abstract

Photocatalytic technology offers significant advantages in addressing water pollution and energy regeneration challenges. Notably, photocatalytic CO₂ reduction technology can convert CO₂ into stable, efficient, and clean carbon compounds such as carbon monoxide, methane, ethylene, and other high-value compounds, providing a novel [...] Read more.

Photocatalytic technology offers significant advantages in addressing water pollution and energy regeneration challenges. Notably, photocatalytic CO₂ reduction technology can convert CO₂ into stable, efficient, and clean carbon compounds such as carbon monoxide, methane, ethylene, and other high-value compounds, providing a novel approach to mitigating the global energy crisis and maintaining the carbon balance. However, traditional semiconductor photocatalytic materials face limitations in photocatalytic degradation and reduction due to their low light energy utilization, severe photocorrosion, rapid photogenerated carrier recombination, and slow electron transport rates. Recent studies have shown that introducing various carrier materials can effectively address these issues. Carrier materials, with their unique properties, enhance semiconductor composite photocatalyst systems, promoting photogenerated carrier separation and improving light energy utilization. This review introduces different carrier materials used in photocatalyst fabrication, systematically explains the preparation strategies for carrier-based composite photocatalysts, and summarizes their applications. Finally, future developments in this field are discussed. This review aims to provide diverse strategies for designing carrier-based photocatalysts, leveraging the special effects of carrier materials to control semiconductor composite modes, interface behaviors, and energy band structures. Full article

(This article belongs to the Special Issue Mineral-Based Composite Catalytic Materials)

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17 pages, 2578 KiB

Open AccessFeature PaperArticle

Sulfur-Doped CoFe/NF Catalysts for High-Efficiency Electrochemical Urea Oxidation and Hydrogen Production: Structure Optimization and Performance Enhancement

by Sirong Li, Lang Yao, Zhenlong Wang, Zhonghe Xu and Xuechun Xiao

Catalysts 2025, 15(3), 285; https://doi.org/10.3390/catal15030285 - 18 Mar 2025

Viewed by 435

Abstract

In this study, a sulfur-doped cobalt–iron catalyst (CoFeS/NF) was synthesized on a nickel foam (NF) substrate via a facile one-step electrodeposition method, and its performance in urea electrolysis for hydrogen production was systematically investigated. Sulfur doping induced significant morphology optimization, forming a highly [...] Read more.

In this study, a sulfur-doped cobalt–iron catalyst (CoFeS/NF) was synthesized on a nickel foam (NF) substrate via a facile one-step electrodeposition method, and its performance in urea electrolysis for hydrogen production was systematically investigated. Sulfur doping induced significant morphology optimization, forming a highly dispersed nanosheet structure, which enhanced the specific surface area increase by 1.9 times compared with the undoped sample, exposing abundant active sites. Meanwhile, the introduction of sulfur facilitated electron redistribution at the surface modulated the valence states of nickel and cobalt, promoted the formation of high-valence Ni³⁺/Co³⁺, optimized the adsorption energy of the reaction intermediates, and reduced the charge transfer resistance. Electrochemical evaluations revealed that CoFeS/NF achieves a current density of 10 mA cm⁻² at a remarkably low potential of 1.18 V for the urea oxidation reaction (UOR), outperforming both the undoped catalyst (1.24 V) and commercial RuO₂ (1.35 V). In addition, the catalyst also exhibited excellent catalytic activity and long-term stability in the total urea decomposition process, which was attributed to the amorphous structure and the synergistic enhancement of corrosion resistance by sulfur doping. This study provides a new idea for the application of sulfur doping strategy in the design of multifunctional electrocatalysts, which promotes the coupled development of urea wastewater treatment and efficient hydrogen production technology. Full article

(This article belongs to the Special Issue Design and Synthesis of Nanostructured Catalysts, 2nd Edition)

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23 pages, 4497 KiB

Open AccessArticle

Eco-Friendly Mechanochemical Fabrication of Polypyrrole/Ag-ZnO Heterostructures for Enhanced Photocatalytic Degradation of Methyl Orange

by Muhammad Khalid Nazir, Muhammad Babar Taj, Azza A. Al-Ghamdi, Afaf Almasoudi, Fatimah Mohammad H. AlSulami, Hadeel M. Banbela, Omar Makram Ali, Muhammad Mahboob Ahmed, Muhammad Imran Khan, Abdallah Shanableh and Javier Fernandez-Garcia

Catalysts 2025, 15(3), 284; https://doi.org/10.3390/catal15030284 - 18 Mar 2025

Viewed by 523

Abstract

A Ppy/Ag-ZnO catalyst was successfully synthesized at room temperature using a novel, green methodology. It involves a mechanically assisted metathesis reaction. The Ppy/Ag-ZnO catalyst was analyzed via X-ray diffraction Technique (XRD), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR), Scanning [...] Read more.

A Ppy/Ag-ZnO catalyst was successfully synthesized at room temperature using a novel, green methodology. It involves a mechanically assisted metathesis reaction. The Ppy/Ag-ZnO catalyst was analyzed via X-ray diffraction Technique (XRD), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV–visible spectroscopy, Brunauer–Emmett–Teller (BET), and zeta potential. Debye Scherrer’s calculation suggested a crystallite size of 2.30 nm for Ppy/Ag-ZnO nanocomposite. SEM confirmed the production of aggregated particles with an average size of 2.65 μm, endorsing the -ve zeta potential value (−6.78 mV) due to the presence of Van der Waals forces among the particles of Ppy/Ag-ZnO. DSC confirms that the strong interfacial interaction between Ag-ZnO and the polar segments of Ppy is responsible for the higher Tg (107 °C) and Tm (270 °C) in Ppy/Ag-ZnO. The surface area and average pore size of Ppy/Ag-ZnO catalyst were determined to be 47.08 cm³/g and 21.72 Å, respectively. Methyl orange (MO) was used as a probe in a photocatalytic reaction of fabricated material, which demonstrated exceptional efficiency, exhibiting a removal rate of 91.11% with a rate constant of 0.028 min⁻¹. Photocatalytic degradation of MO was shown to follow pseudo-first-order kinetics. Full article

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

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19 pages, 3222 KiB

Open AccessArticle

Polyol Formation of Silver@Metal Oxides Nanohybrid for Photocatalytic and Antibacterial Performance

by Jovairya Azam, Zahoor Ahmad, Ali Irfan, Asima Naz, Muhammad Arshad, Rabia Sattar, Mohammad Raish, Bakar Bin Khatab Abbasi and Yousef A. Bin Jardan

Catalysts 2025, 15(3), 283; https://doi.org/10.3390/catal15030283 - 17 Mar 2025

Viewed by 924

Abstract

The polyol method under a single pot has successfully produced a coating of CuO, TiO₂, and the combination of CuO/TiO₂ around Ag NWs under sequential addition. The Ag NWs and their coating with a pure metal oxide and a hybrid [...] Read more.

The polyol method under a single pot has successfully produced a coating of CuO, TiO₂, and the combination of CuO/TiO₂ around Ag NWs under sequential addition. The Ag NWs and their coating with a pure metal oxide and a hybrid of metal oxide were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDX, X-ray photoelectron spectroscopy (XPS), UV–Visible, photoluminescent (PL) spectroscopy, and cyclic voltammetry (CV). The formation of ultra-thin NWs was also been seen in the presence of the TiO₂ coating. The ultra-thin and co-axial coating of each metal oxide and their hybrid form preserved the SPR of the Ag NWs and demonstrated photon harvesting from the 400–800 nm range. The band gap hybridization was confirmed by CV for the Ag@CuO/TiO₂ design, which made the structure a reliable catalyst. Therefore, the material expresses excellent photocatalytic activities for carcinogenic textile dyes such as turquoise blue (TB), sapphire blue (SB), and methyl orange (MO), with and without the reagent H₂O₂. The hybrid form (i.e., Ag@CuO/TiO₂) exhibited degradation within 6 min in the presence of H₂O₂. Additionally, the material showed antibacterial activities against various bacteria (Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Bacillus pumilus) when assayed using broth media. Therefore, the materials have established degrading and disinfection roles suitable for environmental perspectives. The role of coating with each metal oxide and their hybrid texture further improved the growth of Ag NWs. The preparatory route possibly ensued metal–metal oxide and metal–hybrid metal oxide Schottky junctions, which would expectedly transform it into a diode material for electronic applications. Full article

(This article belongs to the Special Issue Heterogeneous Photocatalysis for Cyclic Compound Synthesis or Functionalization, a Promising Approach for Discovery Chemistry)

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21 pages, 4524 KiB

Open AccessReview

Machine Learning-Assisted Catalysts for Advanced Oxidation Processes: Progress, Challenges, and Prospects

by Qinghui Yuan, Xiaobei Wang, Dongdong Xu, Hongyan Liu, Hanwen Zhang, Qian Yu, Yanliang Bi and Lixin Li

Catalysts 2025, 15(3), 282; https://doi.org/10.3390/catal15030282 - 17 Mar 2025

Viewed by 588

Abstract

Advanced oxidation processes (AOPs) are recognized as one of the most effective methods in the field of wastewater treatment, and the selection of catalysts in the oxidation process is very important. In the face of the traditional test trial-and-error method, the method of [...] Read more.

Advanced oxidation processes (AOPs) are recognized as one of the most effective methods in the field of wastewater treatment, and the selection of catalysts in the oxidation process is very important. In the face of the traditional test trial-and-error method, the method of screening advanced oxidation catalysts is time-consuming and inefficient. This paper examines approximately two decades’ worth of literature pertaining to the development of catalysts facilitated by machine learning. A synopsis of the various advanced oxidation processes and reactive oxygen species (ROS) is provided. Subsequently, it is posited that the swift advancement of machine learning (ML) and its algorithmic classification has significantly propelled the progress in ML-assisted catalyst screening, active site prediction, the discovery of acceleration mechanisms, and catalyst structural research, which are subsequently elucidated. Despite ML’s proven efficacy as a tool within the domain of AOPs’ catalysis, the article concludes by presenting challenges and outlining future development strategies, particularly in light of issues pertaining to data quality and quantity, as well as inherent model limitations. Full article

(This article belongs to the Special Issue Nanomaterials in Environmental Catalysis)

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24 pages, 5144 KiB

Open AccessArticle

Synthesis and Antimicrobial Activity of Chalcone-Derived 1,4-Dihydropyridine Derivatives Using Magnetic Fe₂O₃@SiO₂ as Highly Efficient Nanocatalyst

by Dharambeer Singh Malhi, Navneet Kaur, Manvinder Kaur, Haesook Han, Pradip K. Bhowmik, Fohad Mabood Husain, Harvinder Singh Sohal and Meenakshi Verma

Catalysts 2025, 15(3), 281; https://doi.org/10.3390/catal15030281 - 17 Mar 2025

Viewed by 352

Abstract

The growing threat of bacterial resistance, coupled with the increasing costs associated with drug development, poses significant challenges in the discovery of new antibiotics. The present study reports the synthesis and antimicrobial evaluation of 1,4-dihydropyridine (1,4-DHP) derivatives derived from chalcones, using silica-mediated magnetic [...] Read more.

The growing threat of bacterial resistance, coupled with the increasing costs associated with drug development, poses significant challenges in the discovery of new antibiotics. The present study reports the synthesis and antimicrobial evaluation of 1,4-dihydropyridine (1,4-DHP) derivatives derived from chalcones, using silica-mediated magnetic iron oxide, Fe₂O₃@SiO₂ nanoparticles as a nanocatalyst. The nanoparticles were characterized using FT-IR, SEM-EDS, XRD, Zeta-Potential, and VSM techniques to confirm their structure and properties. Among them, the series 8a–e (particularly compound 8c) demonstrated strong antimicrobial activity, with effectiveness comparable to standard drugs Fluconazole and Amoxicillin; this was attributed to the presence of polar groups. Other derivatives exhibited moderate activity, with MICs ranging from 25 to 50 μg/mL, while no significant activity was observed against Gram-negative bacteria. These compounds hold potential as promising antimicrobial agents and warrant further investigation for the development of effective therapies. Full article

(This article belongs to the Special Issue Spectroscopy in Modern Materials Science and Catalysis)

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23 pages, 5288 KiB

Open AccessFeature PaperReview

A Review on Green Hydrogen Production by Aqueous Phase Reforming of Lignocellulose and Derivatives

by Mengjie Li, Weilong Ji, Chunjie Huang, Xiaoqin Si, Qian Liu, Rui Lu and Tianliang Lu

Catalysts 2025, 15(3), 280; https://doi.org/10.3390/catal15030280 - 17 Mar 2025

Viewed by 594

Abstract

With the intensification of the global energy crisis, hydrogen has attracted significant attention as a high-energy-density and zero-emission clean energy source. Traditional hydrogen production methods are dependent on fossil fuels and simultaneously contribute to environmental pollution. The aqueous phase reforming (APR) of renewable [...] Read more.

With the intensification of the global energy crisis, hydrogen has attracted significant attention as a high-energy-density and zero-emission clean energy source. Traditional hydrogen production methods are dependent on fossil fuels and simultaneously contribute to environmental pollution. The aqueous phase reforming (APR) of renewable biomass and its derivatives has emerged as a research hotspot in recent years due to its ability to produce green hydrogen in an environmentally friendly manner. This review provides an overview of the advancements in APR of lignocellulosic biomass as a sustainable and environmentally friendly method for hydrogen production. It focuses on the reaction pathways of various biomass feedstocks (such as glucose, cellulose, and lignin), as well as the types and performance of catalysts used in the APR process. Finally, the current challenges and future prospects in this field are briefly discussed. Full article

(This article belongs to the Special Issue Plant-Derived Biomass Catalytic and Biocatalytic Transformation into Biorefinery Products)

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14 pages, 3497 KiB

Open AccessFeature PaperArticle

CuCl/Ionic Liquid Catalyzed Cascade Transformation of CO₂ and Alkyne-1,2-Diols: Synthesis of Keto-Functionalized Cyclic Carbonates

by Duozhen Chai, Chongli Wang, Jinzhen Liu, Dongfeng Cao, Kaixuan Guo, Yuankun Wang, Ye Yuan and Francis Verpoort

Catalysts 2025, 15(3), 279; https://doi.org/10.3390/catal15030279 - 17 Mar 2025

Viewed by 437

Abstract

The cyclization of propargyl alcohols with CO₂ represents a highly significant method for the utilization of CO₂. The resulting cyclic carbonates possesses high chemical value and hold great potential for applications in battery electrolytes, polymer precursors, and pharmaceutical intermediates. However, [...] Read more.

The cyclization of propargyl alcohols with CO₂ represents a highly significant method for the utilization of CO₂. The resulting cyclic carbonates possesses high chemical value and hold great potential for applications in battery electrolytes, polymer precursors, and pharmaceutical intermediates. However, most existing reports on this cyclization have been limited to simple propargyl alcohol substrates that are substituted with inert alkyl, cycloalkyl, and phenyl groups. For functionalized propargyl alcohols, such as alkyne-1,2-diols, only a single report has been documented thus far. In this study, we have developed an innovative catalytic system comprising cost-effective copper salts and environmentally friendly ionic liquids (CuCl/1-ethyl-3-methylimidazolium acetate) for the cyclization of alkyne-1,2-diols with CO₂. Compared to the previously reported AgF/bulky monophosphine ligand (BrettPhos) system, our system is free of traditional volatile solvents, phosphine ligands, and additives. Notably, this is the first reported Cu(I)-catalyzed system for this cyclization, offering significant advantages in terms of cost-effectiveness and reduced toxicity compared to silver salts. Moreover, the use of ionic liquids ensures considerable recyclability, further enhancing the sustainability and practicality of this approach. Full article

(This article belongs to the Special Issue Ionic Liquids and Eutectic Mixtures for Green Catalytic Processes)

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14 pages, 4939 KiB

Open AccessArticle

Intermetallic Fe₂Mo Nanoparticles on Hierarchical Nanoporous Copper for Efficient Hydrogen Evolution Reaction

by Zhi-Lan Zhou, Yang Liu, Ying Wang, Shu-Pei Zeng, Hang Shi, Xing-You Lang and Qing Jiang

Catalysts 2025, 15(3), 278; https://doi.org/10.3390/catal15030278 - 16 Mar 2025

Viewed by 406

Abstract

Developing cost-effective and high-performance non-precious metal-based electrocatalysts for hydrogen evolution reaction is of crucial importance toward sustainable hydrogen energy systems. Herein, we prepare a novel hybrid electrode featuring intermetallic Fe₂Mo nanoparticles anchored on the hierarchical nanoporous copper skeleton as robust hydrogen [...] Read more.

Developing cost-effective and high-performance non-precious metal-based electrocatalysts for hydrogen evolution reaction is of crucial importance toward sustainable hydrogen energy systems. Herein, we prepare a novel hybrid electrode featuring intermetallic Fe₂Mo nanoparticles anchored on the hierarchical nanoporous copper skeleton as robust hydrogen evolution electrocatalyst by simple and scalable alloying and dealloying methods. By virtue of the highly active intermetallic Fe₂Mo nanoparticles and unique bicontinuous nanoporous copper skeleton facilitating ion/molecule transportation, nanoporous Fe₂Mo/Cu electrode shows excellent hydrogen evolution reaction electrocatalysis, with a low Tafel slope (~71 mV dec⁻¹) to realize ampere-level current density of 1 A cm⁻² at a low overpotential of ~200 mV in 1 M KOH electrolyte. Furthermore, nanoporous Fe₂Mo/Cu electrode exhibits long−term stability exceeding 400 h to maintain ~250 mA cm⁻² at an overpotential of 150 mV. Such outstanding electrocatalytic performance enables the nanoporous Fe₂Mo/Cu electrode to be an attractive hydrogen evolution reaction catalyst for water splitting in the hydrogen economy. Full article

(This article belongs to the Section Electrocatalysis)

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15 pages, 12249 KiB

Open AccessFeature PaperArticle

Unveiling the Role of Copper Valence States in Enhancing the Catalytic Performance of Copper-Modified ZSM-5 for Direct Methane Conversion

by Yunhan Pu, Huajie Zhang, Yanjun Li, Chuan Yu, Xiaofei Song, Chen Yang and Mingli Fu

Catalysts 2025, 15(3), 277; https://doi.org/10.3390/catal15030277 - 16 Mar 2025

Viewed by 474

Abstract

The conversion of methane (CH₄) to methanol (CH₃OH) under mild conditions remains a significant challenge in catalysis. In this study, we introduce a method to adjust the surface valence states of copper species in Cu-ZSM-5 catalysts by annealing under [...] Read more.

The conversion of methane (CH₄) to methanol (CH₃OH) under mild conditions remains a significant challenge in catalysis. In this study, we introduce a method to adjust the surface valence states of copper species in Cu-ZSM-5 catalysts by annealing under different atmospheres (N₂, air, and H₂). Among these, the 10% Cu-ZSM-5 catalyst calcined in H₂ showed outstanding performance, achieving a methanol productivity of 8.08 mmol/(g_cat·h) and 91% selectivity at 70 °C and 3 MPa using H₂O₂ as the oxidant. Comprehensive characterization revealed that H₂ annealing optimized the Cu surface to a lower valence state (predominantly Cu⁺), enhancing CH₄ adsorption and promoting H₂O₂ activation to generate ·OH and ·CH₃ radicals, which drive selective CH₃OH formation. In situ DRIFTS and radical trapping experiments further confirmed the critical role of Cu⁺ in facilitating C-H bond cleavage and suppressing overoxidation. Full article

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14 pages, 3077 KiB

Open AccessArticle

Cu-Doped CeO₂ Supported by MXene Nanosheets for Enhanced Electrosynthesis of Urea from Carbon Dioxide and Nitrate

by Haoxiang Cai, Lang Zhang, Caiyun Wang, Junyang Ding and Xijun Liu

Catalysts 2025, 15(3), 276; https://doi.org/10.3390/catal15030276 - 16 Mar 2025

Viewed by 572

Abstract

Electrocatalytic synthesizing of urea through C-N coupling of CO₂ and NO₃⁻ under ambient conditions is a possible solution for the problem of energy consumption in commercial urea production. Herein, we report a Cu-doped CeO₂ catalyst anchored on delaminated MXene [...] Read more.

Electrocatalytic synthesizing of urea through C-N coupling of CO₂ and NO₃⁻ under ambient conditions is a possible solution for the problem of energy consumption in commercial urea production. Herein, we report a Cu-doped CeO₂ catalyst anchored on delaminated MXene two-dimensional surface. The Cu-CeO₂/MXene catalyst achieves the co-reduction of CO₂ and NO₃⁻ to synthesize urea, obtaining a urea yield rate of 505.1 μg·h⁻¹·mg_cat.⁻¹ with a Faradic efficiency (FE) of 6.3% at −0.8 V versus reversible hydrogen electrode (vs. RHE). Theoretical calculations further demonstrate that Cu doping is capable of enhancing the activity of Cu-Ce sites and promoting C-N coupling and protonation reactions. Full article

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

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17 pages, 4394 KiB

Open AccessArticle

Green Synthesis and Characterization of Copper Oxide Nanoparticles from Durian (Durio zibethinus) Husk for Environmental Applications

by Yan-Peng Liang, Yu-Bin Chan, Mohammod Aminuzzaman, Mohammad Shahinuzzaman, Sinouvassane Djearamane, Kokila Thiagarajah, Siew-Yoong Leong, Ling-Shing Wong and Lai-Hock Tey

Catalysts 2025, 15(3), 275; https://doi.org/10.3390/catal15030275 - 15 Mar 2025

Viewed by 696

Abstract

Landfill leachate, a complex wastewater generated from municipal solid waste (MSW) landfills, presents significant environmental challenges due to its high organic content and toxic pollutants. This study proposes a sustainable solution by employing the green synthesis of copper oxide nanoparticles (CuO NPs) using [...] Read more.

Landfill leachate, a complex wastewater generated from municipal solid waste (MSW) landfills, presents significant environmental challenges due to its high organic content and toxic pollutants. This study proposes a sustainable solution by employing the green synthesis of copper oxide nanoparticles (CuO NPs) using durian (Durio zibethinus) husk extract, which serves as a natural reducing and stabilizing agent. This approach transforms agricultural waste into a valuable resource for environmental remediation. The synthesis was carried out under mild conditions, avoiding harmful chemicals and reducing energy consumption. The CuO NPs were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy to examine their morphology, crystallinity, purity, and optical properties. SEM and HR-TEM analyses revealed mainly spherical nanoparticles with an average size of 35–50 nm and minimal aggregation. XRD analysis confirmed the presence of a highly crystalline monoclinic phase of CuO, while the EDX spectrum showed distinct peaks corresponding to copper (72%) and oxygen (28%) by weight, confirming the high purity of the material. Preliminary tests demonstrated the photocatalytic efficiency of the CuO NPs, achieving up to a 79% reduction in chemical oxygen demand (COD) in landfill leachate. These findings underscore the potential of green-synthesized CuO NPs for environmental applications, offering an innovative, sustainable method for wastewater treatment and supporting the advancement of solid waste management practices. Full article

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13 pages, 2436 KiB

Open AccessArticle

Study on Low-Temperature Pyrolysis of Dioxins in Municipal Solid Waste Incineration Fly Ash Using Water-Washed Synergistic Catalysts

by Xinglei Zhao, Jiamin Ding, Xin Xiao, Chengbo Zhang, Shengyong Lu, Zhanheng Zhu and Sheng Sun

Catalysts 2025, 15(3), 274; https://doi.org/10.3390/catal15030274 - 13 Mar 2025

Viewed by 521

Abstract

Fly ash produced by Municipal Solid Waste Incineration (MSWI) contains significant quantities of dioxins, posing a major challenge for safe disposal. Compared to other high-temperature disposal methods, low-temperature pyrolysis (<500 °C) can efficiently degrade dioxins in fly ash at relatively low temperatures. To [...] Read more.

Fly ash produced by Municipal Solid Waste Incineration (MSWI) contains significant quantities of dioxins, posing a major challenge for safe disposal. Compared to other high-temperature disposal methods, low-temperature pyrolysis (<500 °C) can efficiently degrade dioxins in fly ash at relatively low temperatures. To better understand the effects of water-washing and catalysts on dioxin decomposition during low-temperature pyrolysis, this study investigates the impact of water-washing and three different catalysts (V₂O₅-WO₃/TiO₂, Fe/C, and CaO) on the decomposition of dioxins in washed fly ash (WFA). The results indicate that, despite the fact that water-washing pretreatment causes dioxin enrichment in WFA, the toxic equivalent quantity (TEQ) of dioxins within WFA remains lower at the identical pyrolysis temperature when contrasted with that in raw fly ash (RFA). Low-temperature pyrolysis carried out at 250 °C is capable of degrading 99.3% of the dioxins present in water-washed fly ash, achieving a significantly better performance compared to the raw fly ash, which has a degradation efficiency of merely 80%. Nevertheless, when the temperature is set at 210 °C, the degradation efficiency of the WFA turns out to be relatively low, only reaching 29%. The addition of catalysts remarkably promoted dioxin degradation at 210 °C. Among them, CaO exhibited the most outstanding performance, achieving a degradation efficiency as high as 94.8%. It should be emphasized that the catalyst ratio plays a pivotal role in the degradation process. Specifically, the proportion of CaO should not to be less than 10 wt.%. Full article

(This article belongs to the Section Environmental Catalysis)

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25 pages, 1912 KiB

Open AccessFeature PaperReview

A Review of Materials for Carbon Dioxide Capture

by Ashish Rana and Jean M. Andino

Catalysts 2025, 15(3), 273; https://doi.org/10.3390/catal15030273 - 13 Mar 2025

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Abstract

The increasing concentration of carbon dioxide (CO₂) in the atmosphere is a significant contributor to global warming and climate change. Effective CO₂ capture and storage technologies are critical to mitigating these impacts. This review explores various materials used for CO [...] Read more.

The increasing concentration of carbon dioxide (CO₂) in the atmosphere is a significant contributor to global warming and climate change. Effective CO₂ capture and storage technologies are critical to mitigating these impacts. This review explores various materials used for CO₂ capture, focusing on the latest advancements and their applications. The review categorizes these materials into chemical and physical absorbents, highlighting their unique properties, advantages, and limitations. Chemical absorbents, such as amine-based solutions and hydroxides, have been widely used due to their high CO₂ absorption capacities and established technological frameworks. However, they often suffer from high energy requirements for regeneration and potential degradation over time. Recent developments in ionic liquids (ILs) and polymeric ionic liquids (PILs) offer promising alternatives, providing tunable properties and lower regeneration energy. Physical absorbents, including advanced solvents like nanofluids and ionic liquids as well as industrial processes like selexol, rectisol, and purisol, demonstrate enhanced CO₂ capture efficiency under various conditions. Additionally, adsorbents like activated carbon, zeolites, metal-organic frameworks (MOFs), carbon nanotubes (CNTs), and layered double hydroxides (LDHs) play a crucial role by providing high surface areas and selective CO₂ capture through physical or chemical interactions. This paper summarizes the state of research on different materials and discusses their advantages and limitations while being used in CO₂ capture technologies. This review also discussed multiple studies examining the use of catalysts and absorption mechanisms in combination with different sorbents, focusing on how these approaches enhance the efficiency of absorption and desorption processes. Through a comprehensive analysis, this review aims to provide valuable insights into the type of materials that are most suitable for CO₂ capture and also provides directions for future research in this area. Full article

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

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17 pages, 2725 KiB

Open AccessArticle

Butanol Production by Ethanol Condensation: Improvements and Limitations in the Rational Design of Cu-Ni-MgO/Graphite Catalysts

by Inmaculada Rodríguez-Ramos, Cristina Lopez-Olmos and Antonio Guerrero-Ruiz

Catalysts 2025, 15(3), 272; https://doi.org/10.3390/catal15030272 - 13 Mar 2025

Viewed by 490

Abstract

The advancement in catalytic processes utilizing sustainable raw materials, such as bioethanol, represents a key scientific challenge in this century. One potential approach to producing 1-butanol, a compound primarily obtained from petroleum-derived sources, is through the Guerbet reaction. For this transformation, various multifunctional [...] Read more.

The advancement in catalytic processes utilizing sustainable raw materials, such as bioethanol, represents a key scientific challenge in this century. One potential approach to producing 1-butanol, a compound primarily obtained from petroleum-derived sources, is through the Guerbet reaction. For this transformation, various multifunctional catalysts have been explored, some of which incorporate Cu and/or Ni nanoparticles that facilitate hydrogenation and dehydrogenation reactions, along with magnesium oxide, which provides the necessary acid/base functionality. To promote nanoparticle formation and maximize the exposed active surface area, high-surface-area graphite (HSAG), a hydrophobic and inert support material, emerges as a promising candidate. In this study, different catalyst formulations containing these components were tested under moderate reaction conditions, at temperatures between 440 and 580 K and a pressure of 50 bar. A strong correlation was observed between butanol selectivity and the presence of medium–high strength basic sites, complemented by moderate acidity. Furthermore, optimizing the copper and nickel loadings to 4 wt.% Cu and 1 wt.% Ni significantly minimized the formation of unwanted byproducts. The highest butanol selectivity (44%) was achieved using a 4Cu1Ni-Mg/HSAG catalyst, which had been pretreated in helium at 723 K before H₂ reduction, yielding approximately 9% 1-butanol. Full article

(This article belongs to the Special Issue Carbon-Based Catalysts to Address Environmental Challenges)

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20 pages, 8676 KiB

Open AccessFeature PaperReview

Zinc Indium Sulfide Materials for Photocatalytic Hydrogen Production via Water Splitting: A Short Review

by Lang Yao, Shice Zeng, Shuxiang Yang, Honghua Zhang, Yue Ma, Guangying Zhou and Jianzhang Fang

Catalysts 2025, 15(3), 271; https://doi.org/10.3390/catal15030271 - 13 Mar 2025

Viewed by 552

Abstract

Photocatalytic water splitting for hydrogen production is seen as a promising solution to energy problems due to its eco-friendly and sustainable properties, which have attracted considerable interest. Despite progress, the efficiency and selectivity of solar-driven photocatalytic hydrogen generation are still below optimal levels, [...] Read more.

Photocatalytic water splitting for hydrogen production is seen as a promising solution to energy problems due to its eco-friendly and sustainable properties, which have attracted considerable interest. Despite progress, the efficiency and selectivity of solar-driven photocatalytic hydrogen generation are still below optimal levels, making it a major challenge to effectively harness solar energy for hydrogen production through photocatalytic water splitting. Advancing high-performance semiconductor photocatalysts is seen as key to tackling this issue. Zinc indium sulfide (ZnIn₂S₄) has gained attention in recent years as a promising semiconductor material for photocatalytic hydrogen production, thanks to its advantageous properties. Studies in photocatalysis are shifting toward the continuous development and modification of materials, with the goal of enhancing efficiency and extending their applications in environmental and energy fields. With proper development, the material may eventually be suitable for large-scale commercial use. Recent studies have aimed at boosting the photocatalytic hydrogen evolution (PHE) efficiency of ZnIn₂S₄-based photocatalysts through a range of experimental techniques, including surface modifications, forming semiconductor heterojunctions, doping with metals and nonmetals, defect engineering, and particle size analysis. The purpose of this review is to explain the design strategies for ZnIn₂S₄-based photocatalysts through these approaches and to provide a thorough summary of the latest developments in their role as catalysts for hydrogen production. Full article

(This article belongs to the Special Issue Recent Advances in Photo/Electrocatalytic Water Splitting)

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22 pages, 3017 KiB

Open AccessFeature PaperReview

Advances in the Enzymatic Synthesis of Nucleoside-5′-Triphosphates and Their Analogs

by Maryke Fehlau, Sarah Westarp, Peter Neubauer and Anke Kurreck

Catalysts 2025, 15(3), 270; https://doi.org/10.3390/catal15030270 - 13 Mar 2025

Viewed by 903

Abstract

Nucleoside-5′-triphosphates (5′-NTPs) are essential building blocks of nucleic acids in nature and play an important role in molecular biology, diagnostics, and mRNA therapeutic synthesis. Chemical synthesis has long been the standard method for producing modified 5′-NTPs. However, chemical routes face limitations, including low [...] Read more.

Nucleoside-5′-triphosphates (5′-NTPs) are essential building blocks of nucleic acids in nature and play an important role in molecular biology, diagnostics, and mRNA therapeutic synthesis. Chemical synthesis has long been the standard method for producing modified 5′-NTPs. However, chemical routes face limitations, including low regio- and stereoselectivity, along with the need for protection/deprotection cycles, resulting in low yields, high costs, and lengthy processes. In contrast, enzymatic synthesis methods offer significant advantages, such as improved regio- and stereoselectivity and the use of mild reaction conditions, which often leads to higher product yields in “one-pot” reactions. Despite the extensive review of chemical synthesis routes for 5′-NTPs, there has not yet been any comprehensive analysis of enzymatic approaches. Initially, this review provides a brief overview of the enzymes involved in nucleotide metabolism, introducing valuable biocatalysts for 5’-NTP synthesis. Furthermore, the available enzymatic methods for efficient 5′-NTP synthesis using purified enzymes and starting from either nucleobases or nucleosides are examined, highlighting their respective advantages and disadvantages. Special attention is also given to the importance of ATP regeneration systems for 5′-NTP synthesis. We aim to demonstrate the remarkable potential of enzymatic in vitro cascade reactions, promoting their broader application in both basic research and industry. Full article

(This article belongs to the Special Issue Feature Papers in Catalysis for Pharmaceuticals)

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14 pages, 2707 KiB

Open AccessArticle

Revealing the Electronic Effects Between Pt and W on the Performance of Selective Catalytic Reduction of NO_x with H₂ over Pt-W/SSZ-13

by Hongyan Zhao, Yan Li, Yan Huang, Jianli Wang, Yaoqiang Chen and Haidi Xu

Catalysts 2025, 15(3), 269; https://doi.org/10.3390/catal15030269 - 12 Mar 2025

Cited by 1 | Viewed by 575

Abstract

Selective catalytic reduction of NO_x with H₂ (H₂-SCR) is crucial for eliminating NO_x emissions from hydrogen internal combustion engines (H₂-ICE). Although 1 wt.% Pt/SSZ-13 (Pt/SZ) is a promising H₂-SCR catalyst, it faces challenges such [...] Read more.

Selective catalytic reduction of NO_x with H₂ (H₂-SCR) is crucial for eliminating NO_x emissions from hydrogen internal combustion engines (H₂-ICE). Although 1 wt.% Pt/SSZ-13 (Pt/SZ) is a promising H₂-SCR catalyst, it faces challenges such as a narrow operating window and low N₂ selectivity. Herein, the effects of WO₃ on improving the H₂-SCR performance of Pt/SZ was investigated. Results showed that incorporating 5 wt.% WO₃ significantly widened the temperature window for 80% NO_x conversion and enhanced N₂ selectivity at 90–180 °C. Several characterizations revealed that electrons transfer from W to Pt, so more active Pt⁰ species were formed on 1 wt.% Pt-5 wt.% W/SZ (Pt-5W/SZ). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis indicated that more active monodentate nitrates, nitrites, and NH₄⁺ species were generated on Pt-5W/SZ, which are key intermediates for N₂ formation. Consequently, the temperature windows for NO_x conversion (over 80%) and N₂ selectivity (over 70%) were widened by 65 °C and 66 °C, respectively. This work provides insights into the developing H₂-SCR catalysts with broader operating windows and higher N₂ selectivity. Full article

(This article belongs to the Special Issue Rare Metal Catalysis: From Synthesis to Sustainable Applications)

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17 pages, 7810 KiB

Open AccessArticle

Two-Step Tandem Synthesis of Coumarin Derivatives Containing Bioamide Skeleton Catalyzed by Lipozyme TL IM from Thermomyces lanuginosus in Sustainable Continuous-Flow Microreactors

by Li-Hua Du, Hang Lin, Guo-Neng Fu, Zong-Hao Huang, Yi-Min Chen, Han-Jia Xie, Bing-Lin Yan, Miao-Miao Xue, Ao-Ying Zhang, Lin Wang and Xi-Ping Luo

Catalysts 2025, 15(3), 268; https://doi.org/10.3390/catal15030268 - 12 Mar 2025

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Abstract

Due to their remarkable biological and pharmacological activities such as antibacterial, antifungal, anticoagulant, antioxidant, anticancer, and anti-inflammatory properties, synthesis of coumarins and their derivatives has attracted considerable attention in research and development among both organic and medicinal chemists. In this paper, we demonstrated [...] Read more.

Due to their remarkable biological and pharmacological activities such as antibacterial, antifungal, anticoagulant, antioxidant, anticancer, and anti-inflammatory properties, synthesis of coumarins and their derivatives has attracted considerable attention in research and development among both organic and medicinal chemists. In this paper, we demonstrated for the first time a two-step tandem enzymatic synthesis of coumarin bioamide derivatives through sustainable continuous-flow technology. Salicylaldehyde and dimethyl malonate were firstly reacted to obtain coumarin carboxylate methyl derivatives, which were then reacted with various biogenic amines at 50 °C for about 40 min under the catalysis of lipase TL IM from Thermomyces lanuginosus to obtain coumarin bioamide derivatives in continuous-flow reactors. Reaction parameters such as reaction solvent, reaction catalyst type, reactant ratio, residence time, reaction temperature and comparative experiments with traditional batch process were studied. Ideal product yields (62.7–87.1%) were obtained. Environmentally friendly methanol was applied as the reaction medium. Substantially shorter reaction times as well as a significant increase in the product yield were obtained as compared to the batch process. This innovative approach provides a promising green, efficient and rapid synthesis strategy for pharmaceutical synthesis and further research on novel coumarin bioamide derivatives. Full article

(This article belongs to the Section Biocatalysis)

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11 pages, 5041 KiB

Open AccessFeature PaperArticle

Pore-Rich Ni-Co Spinel Oxides for Treating Soot Oxidation in Engine Exhausts

by Linsheng Xu, Kaixuan Chen, Yuanfeng Li, Yaxiao Ma, Baolong Cui, Jing Xiong and Yuechang Wei

Catalysts 2025, 15(3), 267; https://doi.org/10.3390/catal15030267 - 12 Mar 2025

Viewed by 466

Abstract

Noble metals are still in high demand for exhaust control catalysts in mobile sources. Designing highly efficient and less costly catalysts for soot purification from engine emissions is a challenge. Herein, the Ni-Co spinel oxide catalyst made of earth-abundant elements was synthesized by [...] Read more.

Noble metals are still in high demand for exhaust control catalysts in mobile sources. Designing highly efficient and less costly catalysts for soot purification from engine emissions is a challenge. Herein, the Ni-Co spinel oxide catalyst made of earth-abundant elements was synthesized by a precipitation method. Based on the test results of powder X-ray diffraction (XRD), N₂ adsorption–desorption experiments, the temperature-programmed oxidation of soot (soot-TPO), the temperature-programmed oxidation of NO (NO-TPO), the temperature-programmed reduction in H₂ (H₂-TPR), and the advantages of Ni-Co synergistic catalysts relative to pure NiO and Co₃O₄ oxides were systematically investigated. The NiCo₂O₄ catalyst exhibits excellent catalytic performance and stability during soot oxidation compared with NiO and Co₃O₄ catalysts, i.e., its T₁₀, T₅₀, T₉₀ and S_CO2^m are 316, 356, 388 °C and 99.95%, respectively. The mechanism of the Ni-Co synergy effect for boosting soot oxidation on the spinel oxide catalyst is proposed according to the experimental results of in situ diffuse reflectance infrared Fourier transform spectra (in situ DRIFTS) and the theoretical knowledge of coordination chemistry of metal–NO. This study lays a good foundation for exhaust purification by non-noble metal catalysts for pollution control and sustainable environmental practices. Full article

(This article belongs to the Section Catalytic Materials)

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13 pages, 2516 KiB

Open AccessFeature PaperArticle

Nanorod Heterodimer-Shaped CuS/Zn_xCd_1−xS Heteronanocrystals with Z-Scheme Mechanism for Enhanced Photocatalysis

by Lei Yang, Lihui Wang, Han Xiao, Di Luo, Jiangzhi Zi, Guisheng Li and Zichao Lian

Catalysts 2025, 15(3), 266; https://doi.org/10.3390/catal15030266 - 12 Mar 2025

Viewed by 532

Abstract

The efficient separation of photo-generated electrons and holes is significantly importance for enhancing photocatalytic performance. However, there are few reports on precisely constructing interfaces within a single nanocrystal to investigate the mechanism of photoinduced carrier transfer. In this study, nanorod heterodimer-structured CuS/Zn_x [...] Read more.

The efficient separation of photo-generated electrons and holes is significantly importance for enhancing photocatalytic performance. However, there are few reports on precisely constructing interfaces within a single nanocrystal to investigate the mechanism of photoinduced carrier transfer. In this study, nanorod heterodimer-structured CuS/Zn_xCd_1−xS heteronanocrystals (CuS/ZnCdS HNCs) were successfully synthesized as a typical model to explore the photoinduced carrier dynamics in the photocatalytic hydrogen evolution reaction (HER). The CuS/ZnCdS HNCs exhibited a photocatalytic hydrogen evolution activity of 146 mmol h⁻¹ g⁻¹ under visible light irradiation, which is higher than most reported values. Moreover, after 15 h of hydrogen production cycling tests, we found that the material maintained high hydrogen production performance, indicating excellent stability. The CuS/ZnCdS HNCs achieved an apparent quantum yield (AQY) of 69.2% at 380 nm, which is the highest value reported so far for ZnCdS- or CuS-based photocatalysts. The remarkable activity and stability of the CuS/ZnCdS HNCs were attributed to the strong internal electric field (IEF) and Z-scheme mechanism, which facilitate efficient charge separation, as demonstrated by in situ X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analyses. This discovery provides a new approach for constructing Z-scheme heterogeneous copper-based nanocomposites within nanocrystals and offers guidance for improving photocatalytic activity. Full article

(This article belongs to the Special Issue Photocatalysis: Past, Present, and Future Outlook)

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