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Volume 14
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Catalysts, Volume 14, Issue 10 (October 2024) – 78 articles

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39 pages, 1744 KiB  
Review
Zirconium Phosphates and Phosphonates: Applications in Catalysis
by Anna Donnadio, Monica Pica, Morena Nocchetti and Oriana Piermatti
Catalysts 2024, 14(10), 733; https://doi.org/10.3390/catal14100733 (registering DOI) - 19 Oct 2024
Abstract
This review covers recent advancements in the use of zirconium phosphates and phosphonates (ZrPs) as catalysts or catalyst supports for a variety of reactions, including biomass conversion, acid–base catalysis, hydrogenation, oxidation, and C-C coupling reactions, from 2015 to the present. The discussion emphasizes [...] Read more.
This review covers recent advancements in the use of zirconium phosphates and phosphonates (ZrPs) as catalysts or catalyst supports for a variety of reactions, including biomass conversion, acid–base catalysis, hydrogenation, oxidation, and C-C coupling reactions, from 2015 to the present. The discussion emphasizes the intrinsic catalytic properties of ZrPs, focusing on how surface acidity, hydrophobic/hydrophilic balance, textural properties, and particle morphology influence their catalytic performance across various reactions. Additionally, this review thoroughly examines the use of ZrPs as supports for catalytic species, ranging from organometallic complexes and metal ions to noble metals and metal oxide nanoparticles. In these applications, ZrPs not only enhance the dispersion and stabilization of active catalytic species but also facilitate their recovery and reuse due to their robust immobilization on the solid support. This dual functionality underscores the importance of ZrPs in promoting efficient, selective, and sustainable catalytic processes, making them essential to the advancement of green chemistry. Full article
(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section)
13 pages, 2694 KiB  
Article
Investigating the Impact of Stress on the Optical Properties of GaN-MX2 (M=Mo, W; X=S, Se) Heterojunctions Using the First Principles
by Xu-Cai Zhao, Meng-Yao Dai, Fu-Mei Lang, Can Zhao, Qiao-Yue Chen, Li-Li Zhang, Yi-Neng Huang, Hai-Ming Lu and Xiao-Chuan Qin
Catalysts 2024, 14(10), 732; https://doi.org/10.3390/catal14100732 (registering DOI) - 19 Oct 2024
Abstract
This study used the first-principles-based CASTEP software to calculate the structural, electronic, and optical properties of heterojunctions based on single-layer GaN. GaN-MX2 exhibited minimal lattice mismatches, typically less than 3.5%, thereby ensuring lattice coherence. Notably, GaN-MoSe2 had the lowest binding energy, [...] Read more.
This study used the first-principles-based CASTEP software to calculate the structural, electronic, and optical properties of heterojunctions based on single-layer GaN. GaN-MX2 exhibited minimal lattice mismatches, typically less than 3.5%, thereby ensuring lattice coherence. Notably, GaN-MoSe2 had the lowest binding energy, signifying its superior stability among the variants. When compared to single-layer GaN, which has an indirect band gap, all four heterojunctions displayed a smaller direct band gap. These heterojunctions were classified as type II. GaN-MoS2 and GaN-MoSe2 possessed relatively larger interface potential differences, hinting at stronger built-in electric fields. This resulted in an enhanced electron–hole separation ability. GaN-MoSe2 exhibited the highest value for the real part of the dielectric function. This suggests a superior electronic polarization capability under an electric field, leading to high electron mobility. GaN-MoSe2 possessed the strongest optical absorption capacity. Consequently, GaN-MoSe2 was inferred to possess the strongest photocatalytic capability. The band structure and optical properties of GaN-MoSe2 under applied pressure were further calculated. The findings revealed that stress significantly influenced the band gap width and light absorption capacity of GaN-MoSe2. Specifically, under a pressure of 5 GPa, GaN-MoSe2 demonstrated a significantly narrower band gap and enhanced absorption capacity compared to its intrinsic state. These results imply that the application of stress could potentially boost its photocatalytic performance, making it a promising candidate for various applications. Full article
(This article belongs to the Special Issue New Advances in Photocatalytic Hydrogen Production)
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24 pages, 1319 KiB  
Review
Lewis Acid-Base Site-Assisted In Situ Transesterification Catalysis to Produce Biodiesel
by Zhuangzhuang Zhang, Pan Meng, Hangyu Luo, Zhengfei Pei and Xiaofang Liu
Catalysts 2024, 14(10), 731; https://doi.org/10.3390/catal14100731 (registering DOI) - 19 Oct 2024
Viewed by 126
Abstract
Biodiesel, a potent replacement for petroleum diesel, is derived from fatty acids in biomass through transesterification, which is renewable, non-toxic, and biodegradable and is a powerful replacement for petroleum diesel. Lewis acid has been proven effective for esterification and transesterification. The Lewis base [...] Read more.
Biodiesel, a potent replacement for petroleum diesel, is derived from fatty acids in biomass through transesterification, which is renewable, non-toxic, and biodegradable and is a powerful replacement for petroleum diesel. Lewis acid has been proven effective for esterification and transesterification. The Lewis base enhances the electrophilic and nucleophilic properties of the molecules that bind to it, leading to the remarkable versatility of the Lewis base catalytic reaction. Many studies have shown that Lewis acid/base catalyzed in situ transesterification is a fast and environmentally friendly method for producing biodiesel. The utilization of Lewis acid-base sites to catalyze transesterification has been shown to enhance their efficiency and utilization of acid-base active sites. This review explores biodiesel production by different catalysts using Lewis acid-base sites, the conditions for catalytic transesterification, the effects of different reaction parameters on biodiesel production, and the biodiesel production process. Full article
(This article belongs to the Special Issue Catalytic Conversion of Bioderived Feedstocks to Chemical Platforms and Fuels)
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13 pages, 4292 KiB  
Article
Facile Synthesis of Metal/Carbide Hybrid toward Overall Water Splitting
by Junxiang Mo, Nianqing Fu, Songlin Mu, Jihua Peng, Yan Liu and Guoge Zhang
Catalysts 2024, 14(10), 730; https://doi.org/10.3390/catal14100730 (registering DOI) - 18 Oct 2024
Viewed by 360
Abstract
The development of cost-effective and high-performance bifunctional catalysts for overall water splitting is crucial for achieving sustainable clean energy. In this study, a metal/carbide hybrid (NiFeMo/NiFeMoCx) was prepared through fast and facile cathodic plasma electrolytic deposition. Due to the synergistic effect [...] Read more.
The development of cost-effective and high-performance bifunctional catalysts for overall water splitting is crucial for achieving sustainable clean energy. In this study, a metal/carbide hybrid (NiFeMo/NiFeMoCx) was prepared through fast and facile cathodic plasma electrolytic deposition. Due to the synergistic effect between the metal and carbide, NiFeMo/NiFeMoCx exhibited high activity in both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER), with overpotentials of 230 mV and 60 mV at 10 mA cm−2, respectively. In addition, robust stability was demonstrated during the overall water splitting (1.52 V at 10 mA cm−2, with little degradation after 18 h of catalysis). This work provides a useful strategy for designing advanced water splitting catalysts for real application. Full article
(This article belongs to the Special Issue Recent Applications of Metal Catalysts in Organic Synthesis, 2nd Edition)
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13 pages, 5486 KiB  
Article
A Highly Efficient Catalytic Co-Combustion of Aromatic and Oxygenated Volatile Organic Compounds (VOCs) via H2-Driven Onsite Heating
by Sehrish Munsif, Lutf Ullah, Long Cao, Palle Ramana Murthy, Jing-Cai Zhang and Wei-Zhen Li
Catalysts 2024, 14(10), 729; https://doi.org/10.3390/catal14100729 - 18 Oct 2024
Viewed by 217
Abstract
Catalytic combustion, a highly efficient technique for reducing volatile organic compounds (VOCs), is the focus of this study. We investigate the improved catalytic efficiency of the physical mixing of nanosized Pt and atomically dispersed Co, supported on Al2O3 catalysts (Pt-Co)/Al [...] Read more.
Catalytic combustion, a highly efficient technique for reducing volatile organic compounds (VOCs), is the focus of this study. We investigate the improved catalytic efficiency of the physical mixing of nanosized Pt and atomically dispersed Co, supported on Al2O3 catalysts (Pt-Co)/Al2O3 (PM) for the catalytic combustion of VOCs. The catalyst efficiency is evaluated for the hydrogen-assisted catalytic oxidation of various VOCs, including aromatic and oxygenated VOCs such as benzene, toluene, methanol, and formic acid. Our study aims to understand the impact of hydrogen incorporation on the combustion process of various VOCs. The findings of this work underscore the potential of hydrogen-assisted catalytic ignition, which can achieve ignition at ambient temperature, a significant departure from conventional electric heating that typically requires additional energy to raise the temperature. Various characterization techniques, such as BET, STEM, and XRD, are employed to assess the structure–activity relationship of the catalyst. The optimal hydrogen concentration for complete VOC conversion is 3%. Notably, even at a lower hydrogen concentration of 2%, benzene and methanol reach an ideal ignition temperature of over 500 °C when introduced into the physically mixed catalyst. This study highlights the significant potential of hydrogen-assisted catalytic combustion, inspiring further research and offering a promising method to reduce VOCs effectively. Full article
(This article belongs to the Section Environmental Catalysis)
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20 pages, 5021 KiB  
Article
Advances in Liquid-Phase Synthesis: Monitoring of Kinetics for Platinum Nanoparticles Formation, and Pt/C Electrocatalysts with Monodispersive Nanoparticles for Oxygen Reduction
by Vladimir Guterman, Kirill Paperzh, Irina Novomlinskaya, Ilya Kantsypa, Alina Khudoley, Yana Astravukh, Ilya Pankov and Alexey Nikulin
Catalysts 2024, 14(10), 728; https://doi.org/10.3390/catal14100728 - 17 Oct 2024
Viewed by 263
Abstract
The growing demand for hydrogen–air fuel cells with a proton-exchange membrane has increased interest in the development of scalable technologies for the synthesis of Pt/C catalysts that will allow us to fine-tune the microstructure of such materials. We have developed a new in [...] Read more.
The growing demand for hydrogen–air fuel cells with a proton-exchange membrane has increased interest in the development of scalable technologies for the synthesis of Pt/C catalysts that will allow us to fine-tune the microstructure of such materials. We have developed a new in situ technique for controlling the kinetics of the transformation of a platinum precursor into its nanoparticles and deposited Pt/C catalysts, which might be applicable during the liquid-phase synthesis in concentrated solutions and carbon suspensions. The technique is based on the analysis of changes in the redox potential and the reaction medium coloring during the synthesis. The application of the developed technique under conditions of scaled production has made it possible to obtain Pt/C catalysts with 20% and 40% platinum loading, containing ultra-small metal nanoparticles with a narrow size distribution. The electrochemically active surface area of platinum and the mass activity of synthesized catalysts in the oxygen electroreduction reaction have proved to be significantly higher than those of commonly used commercial analogs. At the same time, despite the small size of nanoparticles, the catalysts’ degradation rate turned out to be the same as that of commercial analogs. Full article
(This article belongs to the Section Catalytic Materials)
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13 pages, 7532 KiB  
Article
The Effects of Support Specific Surface Area and Active Metal on the Performance of Biphenyl Selective Hydrogenation to Cyclohexylbenzene
by Jie Fan, Wei Li, Jingyi Yang, Tao Yang, Zhongyi Liu and Meng Zhang
Catalysts 2024, 14(10), 727; https://doi.org/10.3390/catal14100727 - 17 Oct 2024
Viewed by 245
Abstract
With the rapid development of modern society, the consumption of fossil fuels during the industrial production process produces a significant amount of carcinogens. Converting the highly toxic biphenyl (BP) to the valuable product cyclohexylbenzene (CHB) can decrease the emission of carcinogenic aromatic hydrocarbons. [...] Read more.
With the rapid development of modern society, the consumption of fossil fuels during the industrial production process produces a significant amount of carcinogens. Converting the highly toxic biphenyl (BP) to the valuable product cyclohexylbenzene (CHB) can decrease the emission of carcinogenic aromatic hydrocarbons. In this study, we prepared a series of 20%Ni/SiO2 catalysts with different specific surface areas (SSAs) using the over-volume impregnation method, as well as 20%M/SiO2 (M = Fe, Cu, Co, and Ni) catalysts to highlight the effects of support SSAs and active metal on the performance of BP selective hydrogenation to CHB. The catalysts were characterized by XRD, N2 physisorption, TEM, and H2-TPR, which demonstrated that a high SSA would be helpful for the dispersion of the active metal. The evaluation results revealed that 20%Ni/SiO2-300 exhibited excellent activity and stability in the selective hydrogenation of BP to CHB (BP conversion: 99.6%, CHB yield: 99.3% at the conditions of 200 °C, 3 MPa, 4 h and isopropanol as the solvent) among the catalysts with different SSAs, which was also superior to the performance over the catalysts with other transition metals as the active sites. The structure–activity relationship of the employed catalysts for the selective hydrogenation of BP to CHB was also discussed. Full article
(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section)
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17 pages, 6494 KiB  
Article
Synthesis of Tetrahydrocarbazole-Tethered Triazoles as Compounds Targeting Telomerase in Human Breast Cancer Cells
by Pradeep M. Uppar, Akshay Ravish, Zhang Xi, Keshav Kumar Harish, Arun M. Kumar, Lisha K. Poonacha, Toreshettahally R. Swaroop, Chaithanya Somu, Santosh L. Gaonkar, Mahendra Madegowda, Peter E. Lobie, Vijay Pandey and Basappa Basappa
Catalysts 2024, 14(10), 726; https://doi.org/10.3390/catal14100726 - 16 Oct 2024
Viewed by 387
Abstract
Telomere shortening and the induction of senescence and/or cell death may result from inhibition of telomerase activity in cancer cells. Herein, the properties of carbazole–triazole compounds targeting telomerase in human breast cancer cells are explored. All derivatives were evaluated for loss of viability [...] Read more.
Telomere shortening and the induction of senescence and/or cell death may result from inhibition of telomerase activity in cancer cells. Herein, the properties of carbazole–triazole compounds targeting telomerase in human breast cancer cells are explored. All derivatives were evaluated for loss of viability in MCF-7 breast cancer cells, with compound 5g identified as the most potent within the examined series. Green synthesis was employed using water, a reusable nano-Fe2O3-catalyzed reaction, and an electrochemical method for the synthesis of tetrahydrocarbazole and triazoles. The crystal data of compound 4 is also reported. Furthermore, in silico analysis predicted that compound 5g may target human telomerase. Molecular docking analysis of compound 5g towards hTERT predicted a binding affinity of −6.74 kcal/mol. In flow cytometry assays, compound 5g promoted apoptosis and cell cycle arrest in the G2-M phase. Finally, compound 5g inhibited the enzymatic activity of telomerase in human breast cancer cells. In conclusion, a green synthesized series of carbazole–triazoles that target telomerase in cancer cells is reported. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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14 pages, 2870 KiB  
Article
Immobilization and Kinetic Properties of ß-N-Acetylhexosaminidase from Penicillium oxalicum
by Vladimír Štefuca, Mária Bláhová, Helena Hronská and Michal Rosenberg
Catalysts 2024, 14(10), 725; https://doi.org/10.3390/catal14100725 - 16 Oct 2024
Viewed by 351
Abstract
The application of immobilized enzymes often plays a key role in successfully implementing an economically feasible biocatalytic process at an industrial scale. Designing an immobilized biocatalyst involves solving several tasks, from the selection of the carrier and immobilization method to the characterization of [...] Read more.
The application of immobilized enzymes often plays a key role in successfully implementing an economically feasible biocatalytic process at an industrial scale. Designing an immobilized biocatalyst involves solving several tasks, from the selection of the carrier and immobilization method to the characterization of the kinetic properties of the immobilized enzyme. In this study, we focused on the kinetic properties of free and immobilized ß-N-acetylhexosaminidase (Hex), a promising enzyme for application in the field of biotechnology, especially for the synthesis of bioactive carbohydrates. Hex was immobilized via covalent binding in methacrylate particles. The effect of immobilizing Hex from Penicillium oxalicum into porous particles on kinetic properties was investigated, and mathematical and experimental modeling showed that the kinetic behavior of the enzyme was significantly influenced by diffusion in the particles. Along with the study on kinetics, a simple method was developed to investigate the reversible inhibition of the immobilized enzyme in a continuous-flow system. The method is suitable for application in cases where a chromogenic substrate is used, and here it was applied to demonstrate the inhibitory effects of N-acetyl-glucosaminyl thiazoline (NAG-thiazoline) and O-(2-Acetamido-2-deoxy-D-glucopyranosylidene)amino N-phenyl carbamate ((Z)-PugNAc) on Hex. Full article
(This article belongs to the Section Biocatalysis)
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14 pages, 5326 KiB  
Article
Carbon Materials with Different Dimensions Supported Pt Catalysts for Selective Hydrogenation of 3,4-Dichloronitrobenzene to 3,4-Dichloroaniline
by Nannan Zhan, Yan Xiao, Xingkun Chen, Yuan Tan and Yunjie Ding
Catalysts 2024, 14(10), 724; https://doi.org/10.3390/catal14100724 - 16 Oct 2024
Viewed by 443
Abstract
In this study, carbon materials with different dimensions, including the typical one-dimensional (1D) carbon nanotube (CNT), two-dimensional (2D) graphene (GF), and three-dimensional (3D) activated carbon (AC), were investigated as a support for Pt catalysts for the selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB) to 3,4-dichloroaniline [...] Read more.
In this study, carbon materials with different dimensions, including the typical one-dimensional (1D) carbon nanotube (CNT), two-dimensional (2D) graphene (GF), and three-dimensional (3D) activated carbon (AC), were investigated as a support for Pt catalysts for the selective hydrogenation of 3,4-dichloronitrobenzene (3,4-DCNB) to 3,4-dichloroaniline (3,4-DCAN). Notably, the Pt/CNT catalyst with the lowest dimension exhibited the best conversion of 3,4-DCNB under mild reaction conditions, followed by Pt/GF. Comprehensive characterizations, including XRD, TEM, XPS, and in situ CO DRIFTS, reveal that the dimension of carbon supports plays an important role in the particle size and electronic properties of Pt species, consequently affecting the catalytic performances of Pt catalysts. According to the results, electron-deficient Pt particles with small sizes are more favorable for the hydrogenation of 3,4-DCNB to 3,4-DCAN. In addition, dynamic tests and in situ DRIFTS of 3,4-DCNB indicated that the carbonaceous supports will largely influence the adsorption and activation capacity of the Pt catalysts, so that Pt loaded on CNT and GF are superior to that on the AC. We believe this study will provide good guidance for designing efficient carbon-supported metal catalysts for selective hydrogenation. Full article
(This article belongs to the Section Nanostructured Catalysts)
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3 pages, 150 KiB  
Editorial
Microporous and Mesoporous Materials for Catalytic Applications
by Narendra Kumar
Catalysts 2024, 14(10), 723; https://doi.org/10.3390/catal14100723 - 16 Oct 2024
Viewed by 213
Abstract
The Special Issue “Microporous and Mesoporous Materials for Catalytic Applications has twelve peer-reviewed articles (Contributions 1–12), out of which there are eight research papers (Contributions 1–8) and four review papers (Contributions 9–12) [...] Full article
(This article belongs to the Special Issue Microporous and Mesoporous Materials for Catalytic Applications)
17 pages, 6089 KiB  
Article
Synthesis of ZnPc/BiVO4 Z-Scheme Heterojunction for Enhanced Photocatalytic Degradation of Tetracycline Under Visible Light Irradiation
by Lulu Zhong, Liuyun Chen, Xinling Xie, Zuzeng Qin and Tongming Su
Catalysts 2024, 14(10), 722; https://doi.org/10.3390/catal14100722 - 16 Oct 2024
Viewed by 286
Abstract
The construction of semiconductor heterojunctions is an effective strategy to improve the photocatalytic degradation efficiency of organic pollutants. Herein, ZnPc/BiVO4 Z-scheme heterojunction was synthesized via a physical mixing method and was used for the photocatalytic degradation of tetracycline (TC) under visible light [...] Read more.
The construction of semiconductor heterojunctions is an effective strategy to improve the photocatalytic degradation efficiency of organic pollutants. Herein, ZnPc/BiVO4 Z-scheme heterojunction was synthesized via a physical mixing method and was used for the photocatalytic degradation of tetracycline (TC) under visible light irradiation. Compared with BiVO4 and ZnPc, the 15ZnPc/BiVO4 sample exhibited improved light absorption capacity, and the electron-hole separation efficiency and redox capacity were enhanced due to the formation of the Z-scheme heterojunction. The 15ZnPc/BiVO4 composite exhibited an optimal TC degradation rate of 83.1% within 120 min. Additionally, 15ZnPc/BiVO4 exhibited excellent stability in cycling experiments, which maintained a high TC degradation rate of 79.5% after four cycles. Free radical trapping experiments indicated that superoxide radicals (O2−) were the main active substances in the photocatalytic degradation of TC. Full article
(This article belongs to the Special Issue Nanostructures for Catalysis: From Synthesis and Characterization to Applications)
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20 pages, 5958 KiB  
Article
Dry Reforming of Methane (DRM) over Hydrotalcite-Based Ni-Ga/(Mg, Al)Ox Catalysts: Tailoring Ga Content for Improved Stability
by Ahmed Y. Elnour, Ahmed E. Abasaeed, Anis H. Fakeeha, Ahmed A. Ibrahim, Salwa B. Alreshaidan and Ahmed S. Al-Fatesh
Catalysts 2024, 14(10), 721; https://doi.org/10.3390/catal14100721 - 16 Oct 2024
Viewed by 327
Abstract
Dry reforming of methane (DRM) is a promising way to convert methane and carbon dioxide into syngas, which can be further utilized to synthesize value-added chemicals. One of the main challenges for the DRM process is finding catalysts that are highly active and [...] Read more.
Dry reforming of methane (DRM) is a promising way to convert methane and carbon dioxide into syngas, which can be further utilized to synthesize value-added chemicals. One of the main challenges for the DRM process is finding catalysts that are highly active and stable. This study explores the potential use of Ni-based catalysts modified by Ga. Different Ni-Ga/(Mg, Al)Ox catalysts, with various Ga/Ni molar ratios (0, 0.1, 0.3, 0.5, and 1), were synthesized by the co-precipitation method. The catalysts were tested for the DRM reaction to evaluate their activity and stability. The Ni/(Mg, Al)Ox and its Ga-modified Ni-Ga/(Mg, Al)Ox were characterized by N2 adsorption–desorption, Fourier Transform Infrared Spectroscopy (FTIR), H2-temperature-programmed reduction (TPR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and Raman techniques. The test of catalytic activity, at 700 °C, 1 atm, GHSV of 42,000 mL/h/g, and a CH4: CO2 ratio of 1, revealed that Ga incorporation effectively enhanced the catalyst stability. Particularly, the Ni-Ga/(Mg, Al)Ox catalyst with Ga/Ni ratio of 0.3 exhibited the best catalytic performance, with CH4 and CO2 conversions of 66% and 74%, respectively, and an H2/CO ratio of 0.92. Furthermore, the CH4 and CO2 conversions increased from 34% and 46%, respectively, when testing at 600 °C, to 94% and 96% when the catalytic activity was operated at 850 °C. The best catalyst’s 20 h stream performance demonstrated its great stability. DFT analysis revealed an alteration in the electronic properties of nickel upon Ga incorporation, the d-band center of the Ga modified catalyst (Ga/Ni ratio of 0.3) shifted closer to the Fermi level, and a charge transfer from Ga to Ni atoms was observed. This research provides valuable insights into the development of Ga-modified catalysts and emphasizes their potential for efficient conversion of greenhouse gases into syngas. Full article
(This article belongs to the Special Issue Catalytic Reforming and Hydrogen Production: From the Past to the Future)
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12 pages, 2999 KiB  
Article
Ordered Mesoporous Nitrogen Dope Carbon Synthesized from Aniline for Stabilization of Ruthenium Species in CO2 Hydrogenation to Formate
by Arsalan Haider, Ahmad Masudi, Sunghee Ahn, Kwangho Park, Kyung Rok Lee and Kwang-Deog Jung
Catalysts 2024, 14(10), 720; https://doi.org/10.3390/catal14100720 - 15 Oct 2024
Viewed by 491
Abstract
The hydrogenation of CO2 to produce formic acid has garnered increasing interest as a means to address climate change and promote the hydrogen economy. This research investigates the nanocasting technique for the synthesis of ordered mesoporous nitrogen-doped carbon (MNC-An). KIT-6 functioned as [...] Read more.
The hydrogenation of CO2 to produce formic acid has garnered increasing interest as a means to address climate change and promote the hydrogen economy. This research investigates the nanocasting technique for the synthesis of ordered mesoporous nitrogen-doped carbon (MNC-An). KIT-6 functioned as the silica template, while aniline served as the nitrogen–carbon precursor. The resultant MNC-An exhibits cubic Ia3D geometry, possesses significant mesoporosity, and has a high nitrogen content, which is essential for stabilizing ruthenium single atoms. The catalyst exhibited a specific activity of 252 mmolFAgcat−1 following a 2 h reaction at 120 °C. Moreover, the catalyst exhibited exceptional relative activity during five recycling experiments while preserving its catalytic efficacy. The atomically dispersed ruthenium and its Ru3+ oxidation state demonstrated perseverance both before and after the treatment. The results indicated that the synthesized catalyst possesses potential for the expedited commercialization of CO2 hydrogenation to produce formic acid. The elevated carbon yield, along with excellent thermal stability, renders it a viable substrate for attaching and stabilizing atomically dispersed ruthenium catalysts. Full article
(This article belongs to the Special Issue Catalysis and Catalytic Processes for Valuable Chemical Production from CO2)
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23 pages, 5088 KiB  
Article
Synergistic Effect of NiAl-Layered Double Hydroxide and Cu-MOF for the Enhanced Photocatalytic Degradation of Methyl Orange and Antibacterial Properties
by Iqra Batool, Sadia Aroob, Farheen Anwar, Muhammad Babar Taj, Doaa F. Baamer, Afaf Almasoudi, Omar Makram Ali, Reema H. Aldahiri, Fatimah Mohammad H. Alsulami, Muhammad Imran Khan, Aamir Nawaz, Ihsan Maseeh, Muhammad Khalid Nazir, Sónia A. C. Carabineiro, Abdallah Shanableh and Javier Fernandez-Garcia
Catalysts 2024, 14(10), 719; https://doi.org/10.3390/catal14100719 - 15 Oct 2024
Viewed by 455
Abstract
This study synthesized NiAl-layered double hydroxide (LDH)/Cu-MOF photocatalyst using a simple impregnation method involving NiAl-LDH and Cu-MOF. The successful synthesis was confirmed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential measurements, thermogravimetric analysis (TGA), ultraviolet diffuse [...] Read more.
This study synthesized NiAl-layered double hydroxide (LDH)/Cu-MOF photocatalyst using a simple impregnation method involving NiAl-LDH and Cu-MOF. The successful synthesis was confirmed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential measurements, thermogravimetric analysis (TGA), ultraviolet diffuse reflectance spectroscopy (UV-DRS), N2 adsorption at −196 °C, and electrochemical impedance spectroscopy (EIS). Photocatalysts based on NiAl-LDH, Cu-MOF, and NiAl-LDH/Cu-MOF were used to remove methyl orange (MO) dye from contaminated water. The impact of various factors, including pH, dye concentration, and photocatalyst amount, on MO degradation efficiency was assessed. FTIR analysis was conducted both before and after dye degradation. The optimal degradation conditions were a photocatalyst dose of 25 mg and a pH of 3. Kinetic studies indicated that the degradation of MO dye onto NiAl-LDH/Cu-MOF followed a pseudo-first-order and an L–H or Langmuir–Hinshelwood model. The value of R2 = 0.94 confirms the validity of pseudo-first-order and Langmuir–Hinshelwood (L–H) kinetic models for the photocatalytic degradation of MO dye. This study highlights the importance of developing novel photocatalysts with improved degradation efficiency to protect the water environment. Antibacterial activity was also performed with antibacterial sensibility testing by disk diffusion to determine minimal inhibitory and bactericidal concentrations. In short, NiAl-LDH/Cu-MOF can be helpful for various biomedical and industrial applications. Full article
(This article belongs to the Section Photocatalysis)
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12 pages, 1873 KiB  
Article
Kinetic Modelling of Aromaticity and Colour Changes during the Degradation of Sulfamethoxazole Using Photo-Fenton Technology
by Natalia Villota, Unai Duoandicoechea, Jose Ignacio Lombraña and Ana María De Luis
Catalysts 2024, 14(10), 718; https://doi.org/10.3390/catal14100718 - 14 Oct 2024
Viewed by 377
Abstract
Sulfamethoxazole (SMX) is an antibiotic that is extensively used in veterinary medicine, and its occurrence in wastewater and surface water can reach up to 20 μg/L. SMX is categorized as a pollutant of emerging concern by the US EPA due to its persistence [...] Read more.
Sulfamethoxazole (SMX) is an antibiotic that is extensively used in veterinary medicine, and its occurrence in wastewater and surface water can reach up to 20 μg/L. SMX is categorized as a pollutant of emerging concern by the US EPA due to its persistence and effects on humans and the environment. In this study, photo-Fenton technology is proposed for the removal of SMX. Aqueous solutions of SMX (50.0 mg/L) are treated in a 150 W UV photoreactor, using [Fe2+]0 = 0.5 mg/L and varying [H2O2]0 = 0–3.0 mM. During the reaction, colour (AU) was assessed along with SMX (mg/L), turbidity (NTU), and TC (mg/L). SMX degrades to aromatic intermediates with chromophoric groups, exhibiting colour (yellow to brown) and turbidity. As these intermediates are mineralized into CO2 and H2O, the colour and turbidity of the water lose intensity. Using a molar ratio of 1 mol SMX:10 mol H2O2, the maximum degradation of aromatic species takes place (71% elimination), and colourless water with turbidity < 1 NTU is obtained. A kinetic modelling for aromaticity loss and colour formation as a function of the oxidant concentration has been proposed. The application of this model allows the estimation of oxidant amounts for an efficient removal of SMX under environmentally friendly conditions. Full article
(This article belongs to the Special Issue Environmental Catalysis in Advanced Oxidation Processes, 2nd Edition)
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16 pages, 3975 KiB  
Article
Spirobifluorene-Based D-A Type Conjugated Polymer Photocatalysts for Water Splitting
by Hao Zhao, Pengyao Sun, Hui Xu, Xinyi Xiao, Zhiyuan Kong, Shige Song, Weihao Li, Luzun Liu, Jiadong Wang and Xiaobo Pan
Catalysts 2024, 14(10), 717; https://doi.org/10.3390/catal14100717 - 14 Oct 2024
Viewed by 337
Abstract
Exploring synthetic pathways for efficient photocatalysts has always been a major goal in catalysis. The performance of organic photocatalysts is affected by a variety of complex factors, and how to understand the structure–effect relationship is the key to designing efficient photocatalysts. This work [...] Read more.
Exploring synthetic pathways for efficient photocatalysts has always been a major goal in catalysis. The performance of organic photocatalysts is affected by a variety of complex factors, and how to understand the structure–effect relationship is the key to designing efficient photocatalysts. This work explored the feasibility of constructing large-specific-surface-area conjugated microporous polymers (CMPs) based on stereoscopic units like spirobifluorene and achieving efficient photocatalytic activity by modulating the donor–acceptor (D-A) ratio with dibenzothiophene sulfone. Crosslinked pore structures were successfully constructed, and the specific surface area increased with the ratio of spirobifluorene. When the molar ratio of D-A was 1:20, polymer Spso-3 showed the highest photocatalytic hydrogen production activity, at 22.4 mmol h–1 g–1. The findings indicate that constructing D-A type CMPs should be a promising approach to improving the performance of photocatalytic water separation. The appropriate push–pull effect of the D-A structure promotes the photo-induced separation of electron–hole pairs, and the porous structure built on steric units offers ample space for catalytic reactions. This work could provide case references for structural design and the structure–effect relationship of efficient polymer photocatalysts. Full article
(This article belongs to the Special Issue Exclusive Papers in Green Photocatalysis from China)
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13 pages, 8871 KiB  
Article
Thin Films of Bismuth Oxyhalides (BiOX, X = Cl, Br, I) Deposited by Thermal Evaporation for the Decontamination of Water and Air by Photocatalysis
by Enrique López-Cuéllar, Azael Martínez-de la Cruz, Rodolfo Morales-Ibarra, Marco Garza-Navarro and José Olivares-Cortez
Catalysts 2024, 14(10), 716; https://doi.org/10.3390/catal14100716 - 14 Oct 2024
Viewed by 368
Abstract
Thin films of BiOCl, BiOBr, and BiOI (BiOX) were deposited by thermal evaporation for their potential application in the decontamination of water and air through their photocatalytic activity, which was compared among the three. The BiOX thin films were subjected to characterization through [...] Read more.
Thin films of BiOCl, BiOBr, and BiOI (BiOX) were deposited by thermal evaporation for their potential application in the decontamination of water and air through their photocatalytic activity, which was compared among the three. The BiOX thin films were subjected to characterization through X-ray diffraction, high-resolution transmission electron microscopy, and scanning electron microscopy. Additionally, the optical properties were determined from the diffuse reflectance spectrum obtained with a spectrophotometer. To assess the efficacy of the semiconductor films in water decontamination, the evolution of rhodamine B discoloration and its mineralization was monitored by measuring total organic carbon. The decontaminating activity in the air was evaluated in a gas reactor, measuring the conversion of NOx-type gases. The results demonstrated that the thin films of the three oxides exhibited decontaminating photocatalytic activity in both water and air. However, notable distinctions were observed in the photocatalytic activities of the three bismuth oxyhalides in water, while in air, they exhibited similarities. In aqueous environments, the mineralization percentages exhibited notable variation after 96 h, with the BiOBr film displaying a value of 9.2%/mg and the BiOCl film a value of 3.9%/mg. In contrast, the NO conversion rate in the air was approximately 0.6%/mg for the three oxyhalide films. Full article
(This article belongs to the Section Photocatalysis)
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10 pages, 1900 KiB  
Article
Photocatalytic Ammonia Decomposition Using Dye-Encapsulated Single-Walled Carbon Nanotubes
by Tomoyuki Tajima, Kotone Yano, Kazushi Mukai and Yutaka Takaguchi
Catalysts 2024, 14(10), 715; https://doi.org/10.3390/catal14100715 - 12 Oct 2024
Viewed by 366
Abstract
The photocatalytic decomposition of ammonia to produce N2 and H2 was achieved using single-walled carbon nanotube (SWCNT) nanohybrids. The physical modification of ferrocene-dye-encapsulated CNTs by amphiphilic C60-dendron yielded nanohybrids with a dye/CNT/C60 coaxial heterojunction. Upon irradiation with visible [...] Read more.
The photocatalytic decomposition of ammonia to produce N2 and H2 was achieved using single-walled carbon nanotube (SWCNT) nanohybrids. The physical modification of ferrocene-dye-encapsulated CNTs by amphiphilic C60-dendron yielded nanohybrids with a dye/CNT/C60 coaxial heterojunction. Upon irradiation with visible light, an aqueous solution of NH3 and dye@CNT/C60-dendron nanohybrids produced both N2 and H2 in a stoichiometric ratio of 1/3. The action spectra of this reaction clearly demonstrated that the encapsulated dye acted as the photosensitizer, exhibiting an apparent quantum yield (AQY) of 0.22% at 510 nm (the λmax of the dye). This study reports the first example of dye-sensitized ammonia decomposition and provides a new avenue for developing efficient and sustainable photocatalytic hydrogen production systems. Full article
(This article belongs to the Section Nanostructured Catalysts)
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17 pages, 4953 KiB  
Article
Oxidation of Geraniol on Vermiculite—The Influence of Selected Parameters on the Oxidation Process
by Sylwia Gajewska, Agnieszka Wróblewska, Anna Fajdek-Bieda, Adrianna Kamińska, Joanna Sreńscek-Nazzal, Piotr Miądlicki and Beata Michalkiewicz
Catalysts 2024, 14(10), 714; https://doi.org/10.3390/catal14100714 - 12 Oct 2024
Viewed by 476
Abstract
Geraniol is a compound belonging to the group of monoterpenes that finds many applications in organic syntheses, medicine and cosmetics. The following properties of geraniol and its derivatives are of particular interest in medicine: its anti-inflammatory, antioxidant, antimicrobial and anticancer effects. The geraniol [...] Read more.
Geraniol is a compound belonging to the group of monoterpenes that finds many applications in organic syntheses, medicine and cosmetics. The following properties of geraniol and its derivatives are of particular interest in medicine: its anti-inflammatory, antioxidant, antimicrobial and anticancer effects. The geraniol oxidation process was carried out using a mineral of natural origin—vermiculite. Vermiculite is a catalyst that perfectly fits into modern trends in the organic industry, where the aim is to use cheap, renewable and relatively easily available catalytic materials (vermiculite is found on continents including Africa, North America, South America, Australia and Asia). Preliminary studies on the oxidation process of geraniol on vermiculite was carried out in a glass apparatus using molecular oxygen supplied by means of a bubbler and magnetic stirrer with a heating function. During the oxidation process of geraniol on vermiculite, the influence of the following parameters was examined: the temperature, amount of catalyst and reaction time. The main parameters of the process, on the basis of which the most favorable process conditions were selected, were the selectivity of the transformation to 2,3-epoxygeraniol, citral and 2,3-epoxycitral, and the conversion of geraniol. The composition of the post-reaction mixtures was determined qualitatively and quantitatively using the gas chromatography method. In addition, vermiculite was subjected to instrumental tests, such as XRD, SEM, EDX, FTIR and UV-VIS. Moreover, the specific surface area, pore volume and pore volume distribution were estimated on the basis of N2 sorption at −196 °C and also the acid-site concentration in vermiculite was established. Full article
(This article belongs to the Special Issue Topical Advisory Panel Members' Collection Series: Biomass Catalytic Conversion)
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13 pages, 2087 KiB  
Article
Study on the Acidic Modification of Mesoporous HZSM-5 Zeolite and Its Catalytic Cracking Performance
by Yanbing Tong and Ming Ke
Catalysts 2024, 14(10), 713; https://doi.org/10.3390/catal14100713 - 11 Oct 2024
Viewed by 436
Abstract
Mesoporous HZSM-5 zeolites with nanocrystal stacking morphology were directly synthesized via hydrothermal methods without mesoporous templates. The synthesized mesoporous HZSM-5 was subjected to hydrothermal–citric acid washing treatment. The structural and acidic properties of the samples before and after modification were characterized using various [...] Read more.
Mesoporous HZSM-5 zeolites with nanocrystal stacking morphology were directly synthesized via hydrothermal methods without mesoporous templates. The synthesized mesoporous HZSM-5 was subjected to hydrothermal–citric acid washing treatment. The structural and acidic properties of the samples before and after modification were characterized using various techniques. The catalytic performance for butene conversion to propylene was investigated under atmospheric pressure, 500 °C, and a butene weight hourly space velocity (WHSV) of 10 h−1 in a continuous-flow micro-fixed bed reactor. The results show that propylene selectivity increased significantly from 24.7% before modification to 44%, and propylene yield increased from 22% to 38%. After 2 h of hydrothermal–citric acid washing modification, the catalyst maintained a butene conversion rate of 76% and a selectivity of 47% at 525 °C and a WHSV of 10 h−1 after 130 h of continuous reaction, with a propylene yield of 37%. The results indicate that moderate hydrothermal–citric acid washing modification leads to the removal of aluminum from the zeolite framework, reducing the amount and strength of acid but increasing the mesopore quantity. This helps control the reaction pathways and diffusion of intermediate products, suppresses some side reactions, and improves the selectivity and yield of the desired product, propylene, while significantly enhancing catalytic stability. Full article
(This article belongs to the Section Industrial Catalysis)
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17 pages, 5500 KiB  
Article
Optimization of Palladium-Catalyzed One-Pot Synthesis of Functionalized Furans for High-Yield Production: A Study of Catalytic and Reaction Parameters
by Kheira Haiouani, Sherif Hegazy, Huda Alsaeedi, Mikhael Bechelany and Ahmed Barhoum
Catalysts 2024, 14(10), 712; https://doi.org/10.3390/catal14100712 - 11 Oct 2024
Viewed by 362
Abstract
This study investigates the palladium-catalyzed one-pot synthesis of functionalized furans from 1,3-Dicarbonyl compounds and alkenyl bromides, focusing on various catalysts and reaction parameters. Different catalysts, including PdCl₂(CH₃CN)₂, Pd(OAc)₂, and Pd(acac)2 as well as solvents, bases, and oxidants, were systematically evaluated. PdCl₂(CH₃CN)₂ emerged [...] Read more.
This study investigates the palladium-catalyzed one-pot synthesis of functionalized furans from 1,3-Dicarbonyl compounds and alkenyl bromides, focusing on various catalysts and reaction parameters. Different catalysts, including PdCl₂(CH₃CN)₂, Pd(OAc)₂, and Pd(acac)2 as well as solvents, bases, and oxidants, were systematically evaluated. PdCl₂(CH₃CN)₂ emerged as the most effective catalyst, achieving a remarkable yield of 94%. Optimal reaction conditions were identified as PdCl₂(CH₃CN)₂ in dioxane at 80 °C with K₂CO₃ as the base and CuCl₂ as the oxidant. This study also explored various 1,3-diketones including Cyclohexane-1,3-dione, 5,5-Dimethylcyclohexane-1,3-dione, 2H-Pyran-3,5(4H,6H)-dione, Cyclopentane-1,3-dione, Pentane-2,4-dione, Ethyl 3-oxobutanoate, 1,3-Diphenylpropane-1,3-dione, 1,3-Dip-tolylpropane-1,3-dione, 1,3-Bis(4-chlorophenyl)propane-1,3-dione, and 1,3-Bis(4-bromo- phenyl)propane-1,3-dione, alongside different alkenyl bromides such as allyl bromide, (E)-1-Bromo-3,4-dimethylpent-2-ene, 1-Bromo-3-methylbut-2-ene, 3-Bromocyclohex-1-ene, and (E)-1-Bromohex-2-ene. These variations demonstrated the method’s versatility and the significant impact of substituents on reactivity and reaction yield. These findings highlight the importance of optimizing reaction conditions to maximize efficiency and provide insights into improving catalytic processes for enhanced product yields. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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14 pages, 2649 KiB  
Article
Enhanced Photocatalytic Activity in Photocatalytic Concrete: Synthesis, Characterization, and Comprehensive Performance Assessment of Nano-TiO2-Modified Recycled Aggregates
by Xiucheng Zhang, Weizhi Chen, Wencong Lin, Jiansheng Zheng, Guohui Yan and Xuefei Chen
Catalysts 2024, 14(10), 711; https://doi.org/10.3390/catal14100711 - 11 Oct 2024
Viewed by 644
Abstract
This study presents an exhaustive exploration into the development and rigorous evaluation of nano-TiO2-modified recycled aggregates (NT@RAs) as an environmentally sustainable substitute for natural aggregates in concrete applications. A methodical framework was devised for the synthesis and thorough characterization of NT@RAs, [...] Read more.
This study presents an exhaustive exploration into the development and rigorous evaluation of nano-TiO2-modified recycled aggregates (NT@RAs) as an environmentally sustainable substitute for natural aggregates in concrete applications. A methodical framework was devised for the synthesis and thorough characterization of NT@RAs, emphasizing the optimization of nano-TiO2 loading onto the RA surface and within its intricate porous structure. The investigation encompassed three distinct types of recycled aggregates: recycled glass sands (RGSs), recycled clay brick sands (RCBSs), and recycled concrete sands (RCSs). Of particular interest, NT@RGS, with its properties of an inherently smooth surface texture and low water absorption, was found to exert a favorable influence on the rheological behavior of concrete, manifested in reduced yield stress, thereby underscoring the potential for fine-tuning mix designs to enhance workability. As the substitution levels of NT@RGS and NT@RCBS escalated, an initial decrement in compressive strength was discernible, which subsequently reversed to strength restoration at optimized substitution ratios. This phenomenon is attributed to the synergistic interplay among NT@RA components. Remarkably, NT@RA-incorporated concrete demonstrated unparalleled self-cleaning abilities, surpassing the performance of concrete with direct nano-TiO2 powder incorporation. This comprehensive research contributes significantly to the advancement in sustainable, high-performance photocatalytic construction materials within the realm of concrete technology. It underscores the potential for enhancing not only the rheological and mechanical properties but also the environmental responsiveness of concrete through the innovative utilization of NT@RAs. Full article
(This article belongs to the Special Issue Catalytic Purification of Pollutants and Catalytic Conversion of Solid Wastes, 2nd Edition)
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11 pages, 1431 KiB  
Article
Efficient Catalytic Conversion of Acetate to Citric Acid and Itaconic Acid by Engineered Yarrowia lipolytica
by Yuchen Ning, Renwei Zhang, Huan Liu, Yue Yu, Li Deng and Fang Wang
Catalysts 2024, 14(10), 710; https://doi.org/10.3390/catal14100710 - 10 Oct 2024
Viewed by 520
Abstract
The bioconversion of agricultural and industrial wastes is considered a green and sustainable alternative method for producing high-value biochemicals. As a major catalytic product of greenhouse gases and a by-product in the fermentation and lignocellulose processing industries, acetate is a promising bioconversion raw [...] Read more.
The bioconversion of agricultural and industrial wastes is considered a green and sustainable alternative method for producing high-value biochemicals. As a major catalytic product of greenhouse gases and a by-product in the fermentation and lignocellulose processing industries, acetate is a promising bioconversion raw material. In this work, endogenous and heterologous enzymes were manipulated in Yarrowia lipolytica to achieve the conversion of acetate to high-value citric acid and itaconic acid, respectively. After the combinational expression of the key enzymes in the acetate metabolic pathway, the citric acid synthesis pathway, and the mitochondrial transport system, acetate could be efficiently converted to citric acid. Coupled with the down-regulation of fatty acid synthase expression in the competitive pathway, more acetyl-CoA flowed into the synthesis of citric acid, and the titer reached 15.11 g/L with a productivity of 0.51 g/g acetate by the engineered Y. lipolytica, which is comparable to the results using glucose as the substrate. On this basis, the heterologous cis-aconitate decarboxylase from Aspergillus terreus was introduced into the engineered Y. lipolytica to achieve the catalytic synthesis of itaconic acid from acetate. Combined with investigating the effects of multiple enzymes in the synthesis pathway, the titer of itaconic acid reached 1.87 g/L with a yield of 0.43 g/g DCW by the final engineered strain, which is the highest reported titer of itaconic acid derived from acetate by engineered microbes in shake flasks. It is demonstrated that acetate has the potential to replace traditional starch-based raw materials for the synthesis of high-value organic acids and our work lays a foundation for the rational utilization of industrial wastes and the catalytic products of greenhouse gases. Full article
(This article belongs to the Special Issue Recent Advances in Biocatalysis and Enzyme Engineering)
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11 pages, 2189 KiB  
Article
Nano-TiO2-Enhanced Surface Functionalization of Recycled Concrete Aggregates for Improved Degradation Efficiency of Low-Concentration Sulfur Dioxide
by Xue-Fei Chen, Wei-Zhi Chen, Xiu-Cheng Zhang, Wen-Cong Lin, Jian-Sheng Zheng and Guo-Hui Yan
Catalysts 2024, 14(10), 709; https://doi.org/10.3390/catal14100709 - 10 Oct 2024
Viewed by 442
Abstract
This study investigates the enhancement of recycled concrete aggregate (RCA) surfaces with nano-TiO2 for an improved degradation of low-concentration sulfur dioxide (SO2). Nano-TiO2 particles, known for their photocatalytic properties, were uniformly deposited on RCA surfaces. Upon exposure to SO [...] Read more.
This study investigates the enhancement of recycled concrete aggregate (RCA) surfaces with nano-TiO2 for an improved degradation of low-concentration sulfur dioxide (SO2). Nano-TiO2 particles, known for their photocatalytic properties, were uniformly deposited on RCA surfaces. Upon exposure to SO2 under light irradiation, the functionalized RCA exhibited significantly improved degradation efficiency. This was attributed to the photo-induced oxidation of SO2 by nano-TiO2. Enhanced degradation was further observed under UV light due to increased photoactivation. The nano-TiO2 coating also showed good durability and stability, ensuring long-term effectiveness. The experimental outcomes reveal that TiO2-treated recycled aggregates exhibit an 85% retained photocatalytic activity post five cycles of reuse. Furthermore, the investigation employs a second-order polynomial-based mathematical fitting function to generate a three-dimensional trend surface, visually illustrating the inverse relationships between sulfur dioxide degradation and environmental variables, such as initial concentration and flow rates. Finally, this study demonstrates the potential of nano-TiO2-modified RCA for mitigating the environmental impact of low-concentration SO2, contributing to the development of more sustainable construction materials and broadening RCA’s applications in environmental remediation. Full article
(This article belongs to the Special Issue Designing Catalytic Desulfurization Processes to Prepare Clean Fuels, 2nd Edition)
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12 pages, 2675 KiB  
Article
Vertically Ti3CN@NiFe LDH Nanoflakes as Self-Standing Catalysts for Enhanced Oxygen Evolution Reaction
by Lei He, Qing Tang, Qi Fan, Haizheng Zhuang, Shengchao Wang, Yifan Pang and Kun Liang
Catalysts 2024, 14(10), 708; https://doi.org/10.3390/catal14100708 - 10 Oct 2024
Viewed by 462
Abstract
Hydrogen production from water electrolysis is gaining interest as a source of renewable energy storage due to its high efficiency and low environmental impact. However, the slow kinetics of the oxygen evolution reaction (OER) limits the overall efficiency of electrolyzer systems. This study [...] Read more.
Hydrogen production from water electrolysis is gaining interest as a source of renewable energy storage due to its high efficiency and low environmental impact. However, the slow kinetics of the oxygen evolution reaction (OER) limits the overall efficiency of electrolyzer systems. This study presents the synthesis and characterization of a novel electrocatalyst with a vertical structure, composed of Ti3CN MXene-modified NiFe-layered double hydroxides (LDHs) supported on nickel foam (NF) for efficient OER applications. The 1.0-LDH/3MXNF catalyst exhibits excellent electrocatalytic activity, achieving a low overpotential of 247 mV at a current density of 100 mA cm−2 and a favorable Tafel slope of 67.7 mV/dec. This can be attributed to the transfer of excess electrons from Ti3CN MXene to NiFe-LDH, which reduces the oxidation states of Ni and Fe, resulting in a strong interfacial coupling between Ti3CN MXene and NiFe-LDHs. Additionally, the electrode exhibited exceptional stability, maintaining constant performance with minimal potential degradation over prolonged operation. These findings underscore the potential of hybrid LDH-MXene systems as advanced electrocatalysts for renewable energy applications, paving the way for further innovations in energy conversion technologies. Full article
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12 pages, 6564 KiB  
Article
Tailoring Mesoporosity of Multi-Hydroxyls Hyper-Crosslinked Organic Polymers for Reinforced Ambient Chemical Fixation of CO2
by Zengjing Guo, Shuguang Ning, Shicheng Xu, Yongying Zhang, Yifan Dong and Hongjing Han
Catalysts 2024, 14(10), 707; https://doi.org/10.3390/catal14100707 - 10 Oct 2024
Viewed by 376
Abstract
Ambient condition-determined chemical CO2 fixation affords great promise for remitting the pressure of CO2 release. The construction of a microporous environment easily captures CO2 molecules around the reactive sites of the catalyst to reinforce the reaction process. Herein, multi-hydroxyl-containing hyper-crosslinked [...] Read more.
Ambient condition-determined chemical CO2 fixation affords great promise for remitting the pressure of CO2 release. The construction of a microporous environment easily captures CO2 molecules around the reactive sites of the catalyst to reinforce the reaction process. Herein, multi-hydroxyl-containing hyper-crosslinked organic polymers (HCPs-OH-n) are synthesized by the polymerization of 1,4-dichlorobenzyl (DCX) and m-trihydroxybenzene in the monosaccharide form in a Friedel–Crafts alkylation hypercrosslinking process (FCAHP). By tuning the DCX ratio in the FCAHP, the structural properties can be regulated to create a more microporous surface in the HCPs-OH-n; meanwhile, the formed multi-hydroxyl species in the microporous environment could induce the easy interaction between hydroxyls and epoxides by forming a hydrogen bond, which improves the activation of epoxides during the cycloaddition reaction to synthesize the cyclic carbonates at ambient conditions. The structural properties suggest that HCPs-OH-n possess a large surface area with appreciable microporous and mesoporous distribution. As expected, the HCPs-OH-3 bearing the most abundant mesoporosity affords the highest reactivity in the chemical CO2 fixation to cyclic carbonates and is endowed with rational recoverability. Full article
(This article belongs to the Section Catalytic Materials)
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11 pages, 4066 KiB  
Article
Engineering the C-Terminal Region to Enhance the Thermal Stability of Streptomyces hygroscopicus Transglutaminase
by Zhaoxiang Wang, Kangkang Chen, Song Liu, Jianghua Li and Guocheng Du
Catalysts 2024, 14(10), 706; https://doi.org/10.3390/catal14100706 - 10 Oct 2024
Viewed by 352
Abstract
To enhance the applied value of transglutaminase (TGase), various methods have been employed to improve its catalytic properties. However, most modifications have targeted the N-terminus, while the role of the C-terminus in determining TGase properties has been overlooked. In this study, we focused [...] Read more.
To enhance the applied value of transglutaminase (TGase), various methods have been employed to improve its catalytic properties. However, most modifications have targeted the N-terminus, while the role of the C-terminus in determining TGase properties has been overlooked. In this study, we focused on enhancing the thermal stability of Streptomyces hygroscopicus TGase by engineering its C-terminal region. Modeling revealed that the C-terminal loop interacts with the N-terminal loop through hydrogen bonds between Trp331 and N-terminal residues (Asp19, Ala20, Tyr21). Removing the last C-terminal residue (Ser322) had no significant effect on TGase stability, but deleting additional residues (Trp331, Gly330, Gln299) led to inactivation. Substituting Trp331 with Ala reduced TGase’s half-life at 50 °C and specific activity by 50% and 70%, respectively, highlighting the importance of C-terminal interactions in TGase stability. We also attempted to fuse three self-assembling amphipathic peptides (SAPs) (EAK16, KL15, ELK16) and a C-terminal sequence (IGCIILT) from Sulfolobus tokodaii RNase HI to TGase. The fusion of IGCIILT increased TGase’s half-life by 1.5-fold without affecting specific activity, while the three SAPs had little effect on stability. Structural analysis showed that the fusion of IGCIILT raised TGase’s melting temperature by 5.2 °C and altered its tertiary structure. Our results indicate that the C-terminus is important for modulating TGase properties, and fusing “stabilization tags” like IGCIILT at the C-terminus is a promising strategy to enhance thermal stability. Full article
(This article belongs to the Section Biocatalysis)
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17 pages, 4252 KiB  
Article
Novel Biochar-Modified ZIF-8 Metal–Organic Frameworks as a Potential Material for Optoelectronic and Electrochemical Energy Storage Applications
by Sarah Al-atawi, Meshari M. Aljohani, Taymour A. Hamdalla, S. A. Al-Ghamdi, Abdulrhman M. Alsharari and Syed Khasim
Catalysts 2024, 14(10), 705; https://doi.org/10.3390/catal14100705 - 10 Oct 2024
Viewed by 573
Abstract
Herein, we report the preparation of nanocomposites using activated biochar derived from rice husk (RHBC) by doping with a metal–organic framework, namely the zeolitic imidazolate framework (ZIF-8). The morphological and structural characterization of the prepared nanocomposite was performed using SEM, BET, XRD, FTIR, [...] Read more.
Herein, we report the preparation of nanocomposites using activated biochar derived from rice husk (RHBC) by doping with a metal–organic framework, namely the zeolitic imidazolate framework (ZIF-8). The morphological and structural characterization of the prepared nanocomposite was performed using SEM, BET, XRD, FTIR, TGA, and UV–Vis spectroscopy. The average particle sizes as observed from SEM micrographs for ZIF-8 and ZIF-8@RHBC were 67 nm and 78 nm, respectively. The BET surface analysis of the ZIF-8@RHBC composite showed a value of 308 m2/g and a pore diameter of about 42.56 A°. The inclusion of RHBC in ZIF-8 resulted in a 4% increase in the optical band gap and a 5% increase in the optical conductivity. The electrochemical properties of this nanocomposite were investigated through cyclic voltammetry, and it was observed that ZIF-8@RHBC showed improved CV curves in comparison to bare ZIF-8. The specific capacitance of ZIF-8@RHBC was significantly enhanced from 348 F/g to 452 F/g at a 1 A/g current density after incorporating ZIF-8 into the RHBC matrix. The formation of a mesoporous structure in the ZIF-8@RHBC composite contributed to the improved diffusion rate at the electrode surface, resulting in excellent electrochemical features in the composite. Furthermore, the EIS studies confirmed the reduced charge transfer resistance and increased conduction at the electrode surface in the case of the ZIF-8@RHBC composite. Owing to the ease of its green synthesis and its excellent structural and morphological features and optical and electrochemical properties, this ZIF@RHBC nanocomposite could represent a novel multifunctional material to be used in optoelectronics and energy storage applications. Full article
(This article belongs to the Special Issue Two-Dimensional Materials in Photo(electro)catalysis)
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3 pages, 183 KiB  
Editorial
Catalysts: Advances in the Catalytic Behavior of Ion-Exchange Resins
by Eliana Ramírez, Montserrat Iborra and Javier Tejero
Catalysts 2024, 14(10), 704; https://doi.org/10.3390/catal14100704 - 9 Oct 2024
Viewed by 434
Abstract
Ion-exchange resins have been embraced as a relevant scientific development of the 20th century [...] Full article
(This article belongs to the Special Issue Advances in the Catalytic Behavior of Ion-Exchange Resins)
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