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Catalysts, Volume 14, Issue 2 (February 2024) – 66 articles

Cover Story (view full-size image): Meeting strict environmental regulations and safeguarding public health require the removal of sulfur and nitrogen compounds from fuels. Traditional refinery processes, though effective, face limitations in simultaneously addressing both sulfur and nitrogen contaminants. Contrastingly, non-hydrogen technologies offer promise with mild operating conditions and demonstrated efficacy. Recent advancements highlight successful denitrogenation methods alongside decades of desulfurization research. This review critically assesses existing methodologies, including adsorption, extraction, and oxidative catalysis, and proposes future strategies for integrating desulfurization and denitrogenation processes. By synthesizing current knowledge, this paper paves the way for the development of more sustainable and economically viable fuel technologies. View this paper
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32 pages, 4789 KiB  
Review
Recent Advances in Electrocatalytic Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid by Heterogeneous Catalysts
by Zhiming Ma, Lei Wang, Guangyu Li and Tao Song
Catalysts 2024, 14(2), 157; https://doi.org/10.3390/catal14020157 - 19 Feb 2024
Viewed by 1436
Abstract
The utilization and development of biomass resources is an efficient solution to mitigate the fossil energy crisis. Based on the advantages of mild reaction conditions, rapid reaction, and high conversion, the synthesis of 2,5-furandicarboxylic acid (FDCA) by the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMFOR) [...] Read more.
The utilization and development of biomass resources is an efficient solution to mitigate the fossil energy crisis. Based on the advantages of mild reaction conditions, rapid reaction, and high conversion, the synthesis of 2,5-furandicarboxylic acid (FDCA) by the electrocatalytic oxidation of 5-hydroxymethylfurfural (HMFOR) has attracted considerable attention. This review will summarize the recent advances of HMFOR to FDCA, including the reaction pathway and mechanism, as well as the catalytic performance of various heterogeneous electrocatalysts. The challenges and prospects for HMFOR are also focused on. Finally, it is expected that this work may provide guidance for the design of high-efficiency electrocatalysts and thereby accelerate the industrialization process of biomass utilization. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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14 pages, 3787 KiB  
Article
Unveiling the Exceptional Performance of ZnO/Zn2TiO4 Nanocomposites
by Husnain Ahmad Abbasi, Maha M. Al Moneef, Jahanzeb Khan, Muhammad Hafeez, Muhammad Usman Hameed, Muhammad Abdullah Khan, Shabnam Shahida, Habib Ahmad Abbasi and Sook-Keng Chang
Catalysts 2024, 14(2), 156; https://doi.org/10.3390/catal14020156 - 19 Feb 2024
Viewed by 1019
Abstract
In this study, we engineered a sub-70 nm nanocomposite of ZnO/Zn2TiO4 using a low-temperature solution-phase method with titanium isopropoxide and zinc acetate as precursors, and isopropyl alcohol and water as solvents. The investigation focused on nanocomposite growth by varying precursor [...] Read more.
In this study, we engineered a sub-70 nm nanocomposite of ZnO/Zn2TiO4 using a low-temperature solution-phase method with titanium isopropoxide and zinc acetate as precursors, and isopropyl alcohol and water as solvents. The investigation focused on nanocomposite growth by varying precursor and surfactant concentrations and their efficiency within different pH ranges. All three ZnO/Zn2TiO4 nanocomposites exhibited hexagonal wurtzite ZnO and Zn2TiO4 structures. The crystallite size in these nanocomposites ranged from 39.50 nm to 62.67 nm for ZnO and 21.24 nm to 26.15 nm for Zn2TiO4. Morphological observations using FESEM revealed the formation of dispersed cotton packet-like nanocomposites with sizes ranging from 18 to 350 nm. FTIR analysis showed peaks indicative of Ti–O and Zn–O bond formation, and EDX spectrum confirmed the presence of Ti, O, and Zn. UV spectrums and photocatalytic investigations confirmed the successful formation of ZnO/Zn2TiO4 nanocomposites with notable photocatalytic degradation efficiency for methylene blue dye under various conditions. These findings suggest the potential applicability of the synthesized nanocomposites for environmental pollutant degradation. Full article
(This article belongs to the Topic Advances in Inorganic Synthesis)
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20 pages, 5207 KiB  
Review
Carbon Dioxide Methanation Enabled by Biochar-Nanocatalyst Composite Materials: A Mini-Review
by Mengqi Tang, Ahmed Gamal, Arvind K. Bhakta, Khouloud Jlassi, Aboubakr M. Abdullah and Mohamed M. Chehimi
Catalysts 2024, 14(2), 155; https://doi.org/10.3390/catal14020155 - 19 Feb 2024
Viewed by 1044
Abstract
Due to ever-increasing global warming, the scientific community is concerned with finding immediate solutions to reduce or utilize carbon dioxide (CO2) and convert it in useful compounds. In this context, the reductive process of CO2 methanation has been well-investigated and [...] Read more.
Due to ever-increasing global warming, the scientific community is concerned with finding immediate solutions to reduce or utilize carbon dioxide (CO2) and convert it in useful compounds. In this context, the reductive process of CO2 methanation has been well-investigated and found to be attractive due to its simplicity. However, it requires the development of highly active catalysts. In this mini-review, the focus is on biochar-immobilized nanocatalysts for CO2 methanation. We summarize the recent literature on the topic, reporting strategies for designing biochar with immobilized nanocatalysts and their performance in CO2 methanation. We review the thermochemical transformation of biomass into biochar and its decoration with CO2 methanation catalysts. We also tackle direct methods of obtaining biochar nanocatalysts, in one pot, from nanocatalyst precursor-impregnated biomass. We review the effect of the initial biomass nature, as well as the conditions that permit tuning the performances of the composite catalysts. Finally, we discuss the CO2 methanation performance and how it could be improved, keeping in mind low operation costs and sustainability. Full article
(This article belongs to the Special Issue Nanoparticles in the Catalysis)
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12 pages, 6145 KiB  
Article
Study on the Catalytic Oxidation Modification Effect of Heavy Oil at Low Temperature under the Action of Different Ligand Ferric-Based Systems
by Dichen Tan, Zhaofei Ma, Lian Chen, Yuanzhu Mi and Xuemin Yan
Catalysts 2024, 14(2), 154; https://doi.org/10.3390/catal14020154 - 19 Feb 2024
Viewed by 850
Abstract
This work explores the low-temperature catalytic oxidation of heavy oil (140 °C), resulting in structural changes with reduced heavy components and increased light components. The catalytic oxidation system consists of a catalyst, an oxidant, and a proton donor. Four different complexes of iron-based [...] Read more.
This work explores the low-temperature catalytic oxidation of heavy oil (140 °C), resulting in structural changes with reduced heavy components and increased light components. The catalytic oxidation system consists of a catalyst, an oxidant, and a proton donor. Four different complexes of iron-based catalysts were utilized: ferric oleate, iron naphthenate, EDTA–FeNa, and EDDHA–FeNa. Catalytic oxidation processes with these catalysts produced four types of oxygenated oil, which were then analyzed using group composition analysis and a viscosity test. The results show that EDDHA–FeNa is more favorable for the catalytic oxidation of heavy oil in a low-temperature environment, achieving a viscosity reduction rate of 78.57%. Furthermore, the catalytic performance of heavy oil oxidation was investigated using EDDHA–FeNa as catalyst under three conditions: the amount of catalyst, oxidant and reaction temperature. These findings may provide researchers valuable guidance and principles for the investigation and development of advanced catalytic viscosity reduction of heavy oil. Full article
(This article belongs to the Section Industrial Catalysis)
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13 pages, 3978 KiB  
Article
Templated Synthesis of Cu2S Hollow Structures for Highly Active Ozone Decomposition
by Yishan Jiang, Ying Xu, Qichao Zhang, Xin Zhao, Feng Xiao, Xinbo Wang and Guojun Ma
Catalysts 2024, 14(2), 153; https://doi.org/10.3390/catal14020153 - 19 Feb 2024
Viewed by 937
Abstract
Nowadays, it is highly desired to develop highly active and humidity-resistive ozone decomposition catalysts to eliminate the ozone contaminant, one of the primary pollutants in the air. In this work, a series of Cu2S hollow structured materials were rapidly synthesized using [...] Read more.
Nowadays, it is highly desired to develop highly active and humidity-resistive ozone decomposition catalysts to eliminate the ozone contaminant, one of the primary pollutants in the air. In this work, a series of Cu2S hollow structured materials were rapidly synthesized using different structured Cu2O templates. The Cu2S from porous Cu2O showed the highest ozone catalytic decomposition efficiency of >95% to 400 ppm ozone with a weight hourly space velocity of 480,000 cm3·g−1·h−1 in dry air. Importantly, the conversion remained >85% in a high relative humidity of 90%. The mechanism was explored by diffusive reflectance infrared spectroscopy which showed the decomposition intermediate of O22−, and X-ray photoelectron spectroscopy revealed the dual active site of both Cu and S. The EPR and UPS characterization results also explained the superiority of porous Cu2S catalysts from the material itself. All these results show the effective decomposition of ozone by Cu2S, especially in harsh environments, promising for active ozone elimination. Full article
(This article belongs to the Section Catalytic Materials)
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16 pages, 3056 KiB  
Article
Platinum-Modified Mixed Metal Oxide Electrodes for Efficient Chloralkaline-Based Energy Storage
by Jamylle Y. C. Ribeiro, Gessica O. S. Santos, Aline R. Dória, Iñaki Requena, Marcos R. V. Lanza, Katlin I. B. Eguiluz, Giancarlo R. Salazar-Banda, Justo Lobato and Manuel A. Rodrigo
Catalysts 2024, 14(2), 152; https://doi.org/10.3390/catal14020152 - 18 Feb 2024
Viewed by 1023
Abstract
In this work, a series of novel mixed metal oxide (MMO) electrodes with the composition Ti/RuO2Sb2O4Ptx (0 ≤ x ≤ 10.0) were developed, envisaging their application in a reversible electrochemical cell based on the chloralkaline process [...] Read more.
In this work, a series of novel mixed metal oxide (MMO) electrodes with the composition Ti/RuO2Sb2O4Ptx (0 ≤ x ≤ 10.0) were developed, envisaging their application in a reversible electrochemical cell based on the chloralkaline process as an energy storage system. These electrodes were synthesized via the ionic liquid method. Comprehensive physical, chemical, and electrochemical characterizations were conducted to evaluate their performance. The feasibility of employing these electrodes within reversible processes was explored, using the products generated during the electrolytic operation of the system for fuel cell operation. During the electrolyzer operation, higher current densities resulted in enhanced current efficiencies for the production of oxidized chlorine species. Notably, the presence of platinum in the catalyst exhibited a negligible impact on the coulombic efficiency at low current densities where water oxidation predominates. However, at higher current densities, the presence of platinum significantly improved coulombic efficiency, approaching values of approximately 60%. Transitioning to a fuel cell operation, despite the improved kinetic performance associated with a higher platinum content, the process efficiency was predominantly governed by ohmic losses. Curiously, the MMO electrode made without platinum (Ti/(RuO2)70-(Sb2O4)30) displayed the lowest ohmic losses. This study establishes optimal conditions for future investigations into this promising possibility, which holds great potential for energy storage via chloralkaline-based reversible reactions. Full article
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19 pages, 5532 KiB  
Article
Influence of Particle Size of CeO2 Nanospheres Encapsulated in SBA-15 Mesopores on SO2 Tolerance during NH3-SCR Reaction
by Xinyu Han, Mengyao Bian, Kaijie Liu, Xin Yang, Daying Zheng, Xiangguang Yang and Yibo Zhang
Catalysts 2024, 14(2), 151; https://doi.org/10.3390/catal14020151 - 18 Feb 2024
Viewed by 976
Abstract
Ce-based selective catalytic reductions with an NH3 (NH3-SCR) catalyst have emerged as a focal point in denitrification catalyst research. However, the correlation between the structural characteristics of Ce-based catalysts and the influence of CeO2 nanoparticle size on SO2 [...] Read more.
Ce-based selective catalytic reductions with an NH3 (NH3-SCR) catalyst have emerged as a focal point in denitrification catalyst research. However, the correlation between the structural characteristics of Ce-based catalysts and the influence of CeO2 nanoparticle size on SO2 resistance remains unclear. CeO2 nanospheres with different sizes of less than 10 nm were synthesized, and a series of supported CeO2/SBA-15 catalysts were prepared according to the 10 nm pore size of SBA-15. These catalysts were used to explore the influence of the size of the CeO2 nanospheres on these catalysts, specifically on their SO2 resistance in NH3-SCR reactions. With the increase in size, their SO2 resistance became stronger. The results of NH3-TPD, H2-TPR, and XPS indicated that the catalyst with the largest particle size had the lowest adsorption of SO2, which was attributed to more acid sites and a mutual effect between Si and Ce, resulting in the best SO2 resistance. It was also observed that there was less sulfate deposition on the catalyst by thermogravimetric analysis. In situ DRIFTs revealed that after SO2 poisoning, the NH3-SCR reaction on the catalyst predominantly follows the E-R mechanism. This study offers recommendations for the development of Ce-based SO2-resistant NH3-SCR catalysts, specifically focusing on the synthesis and interaction of nanomaterials. Full article
(This article belongs to the Special Issue Rare Earth Catalysis: From Synthesis to Sustainable Applications)
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15 pages, 3391 KiB  
Article
Investigating the Impact of Na2WO4 Doping in La2O3-Catalyzed OCM Reaction: A Structure–Activity Study via In Situ XRD-MS
by Danyu Wang, Junyu Lang, Zhehao Qiu, Ningxujin Ding and Yong Yang
Catalysts 2024, 14(2), 150; https://doi.org/10.3390/catal14020150 - 18 Feb 2024
Viewed by 884
Abstract
The La2O3 catalyst exhibits good performance in OCM reactions for its promising C2 selectivity and yield. Previous studies have affirmed that the formation of carbonates in La2O3 impedes the catalyst’s activity as a result of poisoning [...] Read more.
The La2O3 catalyst exhibits good performance in OCM reactions for its promising C2 selectivity and yield. Previous studies have affirmed that the formation of carbonates in La2O3 impedes the catalyst’s activity as a result of poisoning from CO2 exposure. In this study, a series of Na2WO4-impregnated La2O3 catalysts were synthesized to investigate the poisoning-resistant effect. The bulk phase and kinetics of the catalysts were analyzed in reactors employed with in situ XRD-MS and online MS, focusing on the CO2 adsorption on La2O3 and the phase transition process to La2O2CO3 in temperature zone correlated to OCM light-off. In situ XRD analysis revealed that, with Na2WO4 doped, CO2 exposure at elevated temperatures formed La2O2CO3 in tetragonal crystal phases, exhibiting distinctive differences from the hexagonal phase carbonates in undoped commercial La2O3. The ability to develop tetragonal or monoclinic La2O2CO3 was suggested as a descriptor to assess the sensitivity of La2O3 catalysts to CO2 adsorption, a tunable characteristic found in this study through varying Na2WO4 doping levels. Coupled XRD-MS analysis of CO2 adsorption uptake and phase change further confirmed a positive dependence between the resistivity of La2O3 catalyst to CO2 adsorption and its low-temperature C2 selectivity. The results extended the previous CO2 poisoning effect from multiple perspectives, offering a novel modification approach for enhancing the low-temperature performance of La2O3 catalysts in OCM. Full article
(This article belongs to the Special Issue Heterogeneous Catalysis for Selective Hydrogenation)
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14 pages, 3547 KiB  
Article
Magnetic Metallic Nanoparticles Coated with Carbon for the Catalytic Removal of Bromate from Water
by Patrícia S. F. Ramalho, Olívia Salomé G. P. Soares, José J. M. Órfão and Manuel Fernando R. Pereira
Catalysts 2024, 14(2), 149; https://doi.org/10.3390/catal14020149 - 17 Feb 2024
Viewed by 972
Abstract
Bromate, often detected in drinking water, is associated with a significant risk of cancer. Catalytic reduction has been recognized as an effective treatment technique to remove ions by reducing them over metal catalysts in the presence of a reducing agent, usually hydrogen. This [...] Read more.
Bromate, often detected in drinking water, is associated with a significant risk of cancer. Catalytic reduction has been recognized as an effective treatment technique to remove ions by reducing them over metal catalysts in the presence of a reducing agent, usually hydrogen. This work aims to synthesize metallic magnetic nanoparticles of iron oxide (FeO) and mixed iron oxides with manganese (MnFeO), cobalt (CoFeO), and copper (CuFeO) coated with carbon via chemical vapor deposition (C-MNP) to be applied as catalysts to the reduction of bromate in water. The use of magnetic nanoparticles coated with carbon enables catalyst recovery via magnetic separation and takes advantage of the catalytic properties of the carbon materials. The iron particles proved to be the most promising catalysts for the reduction of bromate into bromide, the highest removal being obtained with the CFeO@CVD750 sample, resulting in a 99% conversion after 120 min of reaction under the conditions tested. Due to its magnetic nature, the catalytic material was easily removed after the reaction and applied in four consecutive cycles without losing its catalytic properties. These results highlight the great potential of carbon-coated magnetic nanoparticles for reducing bromate in water. Full article
(This article belongs to the Section Environmental Catalysis)
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14 pages, 2302 KiB  
Article
Immobilization of Alcohol Dehydrogenases on Silica-Based Supports and Their Application in Enantioselective Ketone Reductions
by Daria Armani, Oreste Piccolo and Antonella Petri
Catalysts 2024, 14(2), 148; https://doi.org/10.3390/catal14020148 - 17 Feb 2024
Viewed by 1043
Abstract
The use of immobilized alcohol dehydrogenases (ADHs) offers numerous advantages, especially in the reaction conditions required by industrial applications. Looking for more efficient and cost-effective methods of ADH immobilization, in this study we explored silica-based supports as an alternative to the use of [...] Read more.
The use of immobilized alcohol dehydrogenases (ADHs) offers numerous advantages, especially in the reaction conditions required by industrial applications. Looking for more efficient and cost-effective methods of ADH immobilization, in this study we explored silica-based supports as an alternative to the use of functionalized polymeric resins. Three commercially available ADHs were immobilized by adsorption and covalent bond formation. The obtained supported biocatalysts were applied for the bioreduction of acetophenone and some derivatives with good yields and excellent enantioselectivity. The important intermediate (S)-1-[3,5-bis(trifluoromethyl)phenyl]ethanol was obtained with a high enantiomeric excess (>99%) by using the highest performing immobilized ADH sample. The reusability of this biocatalyst was investigated in a flow system for five consecutive runs; the experiments showed that the biocatalyst could be recycled without a loss of activity and enantioselectivity. Finally, cross-linking with the glutaraldehyde of the supported biocatalyst was also carried out to prevent the leaching of the enzyme during the catalytic reactions. Full article
(This article belongs to the Special Issue Immobilized Biocatalysts, 3rd Edition)
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17 pages, 9298 KiB  
Article
TiO2/Zeolite Composites for SMX Degradation under UV Irradiation
by Saule Mergenbayeva, Zhanibek Abitayev, Milana Batyrbayeva, John Vakros, Dionissios Mantzavinos, Timur Sh. Atabaev and Stavros G. Poulopoulos
Catalysts 2024, 14(2), 147; https://doi.org/10.3390/catal14020147 - 16 Feb 2024
Viewed by 965
Abstract
Sulfamethoxazole (SMX) is a common antibiotic that is considered an emerging pollutant of water bodies, as it is toxic for various aquatic species. TiO2-based photocatalysis is a promising method for SMX degradation in water. In this work, TiO2/zeolite (Z-45 [...] Read more.
Sulfamethoxazole (SMX) is a common antibiotic that is considered an emerging pollutant of water bodies, as it is toxic for various aquatic species. TiO2-based photocatalysis is a promising method for SMX degradation in water. In this work, TiO2/zeolite (Z-45 loaded with TiO2 labeled as TZ and ZSM-5 loaded with TiO2 labeled as TZSM) composites were prepared by mechanical mixing and liquid impregnation methods, and the photocatalytic performance of these composites (200 mg·L−1) was investigated toward the degradation of SMX (30 mg·L−1) in water under UV light (365 nm). The pseudo-first-order reaction rate constant of the TZSM1450 composite was 0.501 min−1, which was 2.08 times higher than that of TiO2 (k = 0.241 min−1). Complete SMX degradation was observed in 10 min using the UV/TZSM1450 system. The mineralization ability in terms of total organic carbon (TOC) removal was also assessed for all of the prepared composites. The results showed that 65% and 67% of SMX could be mineralized within 120 min of photocatalytic reaction by TZSM2600 and TZSM1450, respectively. The presence of Cl and CO32 anions inhibited the degradation of SMX, while the presence of NO3 had almost no effect on the degradation efficiency of the UV/TZSM1450 system. The electrical energy per order estimated for the prepared composites was in the range of 68.53–946.48 kWh m−3 order−1. The results obtained revealed that the TZSM1450 composite shows promising potential as a photocatalyst for both the degradation and mineralization of SMX. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis: Design, Characterization and Applications)
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22 pages, 2707 KiB  
Review
Metal-Based Heterogeneous Catalysts for the Synthesis of Valuable Chemical Blends via Hydrodeoxygenation of Lignin-Derived Fractions
by Marvin Chávez-Sifontes and María Ventura
Catalysts 2024, 14(2), 146; https://doi.org/10.3390/catal14020146 - 16 Feb 2024
Viewed by 1131
Abstract
Currently, many research projects are focused on the conversion of renewable raw materials into chemicals and fuels. Lignocellulosic biomass is a raw material used for the production of bio-oils and black liquors. These biomass-derived fractions offer promising paths for the production of valuable [...] Read more.
Currently, many research projects are focused on the conversion of renewable raw materials into chemicals and fuels. Lignocellulosic biomass is a raw material used for the production of bio-oils and black liquors. These biomass-derived fractions offer promising paths for the production of valuable chemical products. Various catalytic methods have been investigated for upgrading the biomass-derived fractions. Researchers are interested in the hydrodeoxygenation process (HDO); in this process, the oxygen groups are eliminated by breaking the C-O bonds and water as a product. Incorporating heterogeneous catalysts (i.e., noble metals, transition metals, and metal sulfides) improves this process. Most HDO review articles describe catalytic results for model phenolic compounds. However, there is also a need to investigate the catalytic activity of real biomass-derived fractions. This paper explains research results regarding the upgrading of lignin-derived fractions (i.e., black liquors) by HDO. The paper has been organized according to the type of heterogeneous catalyst and shows compelling results based on different experimental conditions. The final sections present an analysis of the documented results and outline perspectives about integrating lignin into the biorefinery framework. Full article
(This article belongs to the Special Issue New Advances in Metal Oxide Catalysts)
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17 pages, 4753 KiB  
Article
Nickel-Based Single-Atom Alloys for Methane Dehydrogenation and the Effect of Subsurface Carbon: First-Principles Investigations
by Naiyuan Dong, Tanglaw Roman and Catherine Stampfl
Catalysts 2024, 14(2), 145; https://doi.org/10.3390/catal14020145 - 16 Feb 2024
Viewed by 1148
Abstract
Using ab initio calculations, the reaction path for methane dehydrogenation over a series of Ni-based single-atom alloys (Cu, Fe, Pt, Pd, Zn, Al) and the effect that subsurface carbon at the Ni(111) surface has on the reaction barriers are investigated. Due to the [...] Read more.
Using ab initio calculations, the reaction path for methane dehydrogenation over a series of Ni-based single-atom alloys (Cu, Fe, Pt, Pd, Zn, Al) and the effect that subsurface carbon at the Ni(111) surface has on the reaction barriers are investigated. Due to the well-known problem of coking for Ni-based catalysts, the adsorption and associated physical properties of 0.25 ML, 1.0 ML, and 2 ML of carbon on the Ni(111) surface of various sites are first studied. It is found that the presence of subsurface carbon reduces the stability of the intermediates and increases the reaction barriers, thus reducing the performance of the Ni(111) catalyst. The presence of Al, Zn, and Pt is found to reduce the barriers for the CH4 → CH3 + H and CH3 → CH2 + H (Pt); and CH → C + H (Al, Zn) reactions, while Ni(111) yields the lowest barriers for the CH2 → CH + H reaction. These results thus suggest that doping the Ni surface with both Al or Zn atoms and Pt atoms, functioning as distinct active sites, may bring about an improved reactivity and/or selectivity for methane decomposition. Furthermore, the results show that there can be significant adparticle–adparticle interactions in the simulation cell, which affect the reaction energy diagram and thus highlight the importance of ensuring a common reference energy for all steps. Full article
(This article belongs to the Special Issue Application of Catalysts in CO2 Capture, Production and Utilization)
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32 pages, 9982 KiB  
Article
Preparation and Property Characterization of Eu2SmSbO7/ZnBiEuO4 Heterojunction Photocatalysts and Photocatalytic Degradation of Chlorpyrifos under Visible Light Irradiation
by Jingfei Luan, Yichun Wang, Ye Yao, Liang Hao, Jun Li and Yu Cao
Catalysts 2024, 14(2), 144; https://doi.org/10.3390/catal14020144 - 15 Feb 2024
Viewed by 1013
Abstract
Eu2SmSbO7 and ZnBiEuO4 were synthesized for the first time using the hydrothermal method. Eu2SmSbO7/ZnBiEuO4 heterojunction photocatalyst (EZHP) was synthesized for the first time using the solvothermal method. The crystal cell parameter of Eu2 [...] Read more.
Eu2SmSbO7 and ZnBiEuO4 were synthesized for the first time using the hydrothermal method. Eu2SmSbO7/ZnBiEuO4 heterojunction photocatalyst (EZHP) was synthesized for the first time using the solvothermal method. The crystal cell parameter of Eu2SmSbO7 was 10.5547 Å. The band gap width of Eu2SmSbO7 was measured and found to be 2.881 eV. The band gap width of ZnBiEuO4 was measured and found to be 2.571 eV. EZHP efficiently degraded the pesticide chlorpyrifos under visible light irradiation (VLID). After VLID of 160 min, the conversion rate of the chlorpyrifos concentration reached 100%, while the conversion rate of the total organic carbon (TOC) concentration was 98.02% using EZHP. After VLID of 160 min, the photocatalytic degradation conversion rates of chlorpyrifos using EZHP were 1.13 times, 1.19 times, and 2.84 times those using Eu2SmSbO7, ZnBiEuO4, and nitrogen-doped titanium dioxide (N-doped TiO2), respectively. The photocatalytic activity could be ranked as follows: EZHP > Eu2SmSbO7 > ZnBiEuO4 > N-doped TiO2. The conversion rates of chlorpyrifos were 98.16%, 97.03%, 96.03%, and 95.06% for four cycles of experiments after VLID of 160 min using EZHP. This indicated that EZHP was stable and could be reused. In addition, the experiments with the addition of capture agents demonstrated that the oxidation removal ability of three oxidation free radicals for degrading chlorpyrifos obeyed the following order: hydroxyl radical > superoxide anion > holes. This study examined the intermediates of chlorpyrifos during the photocatalytic degradation of chlorpyrifos, and a degradation path was proposed, at the same time, the degradation mechanism of chlorpyrifos was revealed. This study provides a scientific basis for the development of efficient heterojunction photocatalysts. Full article
(This article belongs to the Topic New Materials and Advanced Applications in Photocatalysis)
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11 pages, 1445 KiB  
Article
Hydrogenation of Styrene-Butadiene Rubber Catalyzed by Tris(triisopropylphosphine)hydridorhodium(I)
by Minghui Liu, Wenxin Li, Chengzhuo Zheng, Fei Yuan, Hui Wang, Chengdong Wang, Qinmin Pan and Garry L. Rempel
Catalysts 2024, 14(2), 143; https://doi.org/10.3390/catal14020143 - 13 Feb 2024
Viewed by 1045
Abstract
The hydrogenation of C=C bonds in styrene−butadiene rubber (SBR), catalyzed by RhH(P(i-Pr)3)3, was experimentally investigated. Tris(triisopropylphosphine)hydridorhodium(I), RhH(P(i-Pr)3)3 (i-Pr=CH(CH3)2) was prepared by using rhodium chloride (RhCl3), tetrahydrofuran (THF), triisopropylphosphine (P(i-Pr)3 [...] Read more.
The hydrogenation of C=C bonds in styrene−butadiene rubber (SBR), catalyzed by RhH(P(i-Pr)3)3, was experimentally investigated. Tris(triisopropylphosphine)hydridorhodium(I), RhH(P(i-Pr)3)3 (i-Pr=CH(CH3)2) was prepared by using rhodium chloride (RhCl3), tetrahydrofuran (THF), triisopropylphosphine (P(i-Pr)3) and a sodium mercury amalgam. The effect of catalyst/polymer ratio, reaction temperature, and hydrogen pressure on the reactivity of the catalytic system has been studied. The optimal experimental condition was obtained. The hydrogenated styrene-butadiene rubber (HSBR) was analyzed by FT-IR and 1H-NMR. In the absence of any additives, the conversion of C=C bonds in SBR could easily reach 95% in a short period of time, and no obvious cross-linking was observed. The dynamic properties of SBR did not change after the hydrogenation of the unsaturated C=C bonds. A preliminary reaction mechanism was also proposed. This study provides a new route, not only for the chemical modification of SBR by using a rhodium complex but also for the hydrogenation of other unsaturated polymers, such as diene-based rubbers. Full article
(This article belongs to the Section Catalysis in Organic and Polymer Chemistry)
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14 pages, 4725 KiB  
Communication
The Green Synthesis of Biodiesel via Esterification in Water Catalyzed by the Phosphotungstic Acid–Functionalized Hydrophobic MCM–41 Catalyst
by Dengke Li, Qinghao Shi, Fengbing Liang and Dexin Feng
Catalysts 2024, 14(2), 142; https://doi.org/10.3390/catal14020142 - 13 Feb 2024
Viewed by 1128
Abstract
Biodiesel is a non-toxic and environmentally friendly fuel that is made from renewable biological sources. It can replace petrochemical diesel and has very broad application prospects. However, the main raw materials in biodiesel are animal and plant oils, which present the problems of [...] Read more.
Biodiesel is a non-toxic and environmentally friendly fuel that is made from renewable biological sources. It can replace petrochemical diesel and has very broad application prospects. However, the main raw materials in biodiesel are animal and plant oils, which present the problems of high costs and a lack of resources. The current research primarily emphasizes the transesterification process, with comparatively less focus on the esterification of fatty acids. In this paper, a series of phosphotungstic acid (PTA)-functionalized hydrophobic MCM–41 catalysts, OTS–PTA–MCM–41(Cx), were synthesized and used to catalyze the esterification of long-chain fatty acids with methanol in water. The experimental results show that the yield of esterification reached a maximum when catalyzed by OTS–PTA–MCM–41(Cx) and synthesized with a template agent with two carbon atoms less than the number of carbon atoms of a fatty acid. The effects of different reaction variables were investigated to optimize the reaction conditions for the maximum conversion. The stability of the catalyst was also verified. Finally, a mixed catalyst was used to catalyze in situ the esterification of fatty acids in a fermentation broth, which reached a high level (close to 90%). This paper provides references for the synthesis of a hydrophobic solid acid catalyst and green synthesis by esterification reactions in an aqueous solution and a fermentation broth system. Full article
(This article belongs to the Section Catalytic Materials)
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26 pages, 5714 KiB  
Review
Influence of Impurities in the Chemical Processing Chain of Biomass on the Catalytic Valorisation of Cellulose towards γ-Valerolactone
by Preeti Kashyap, Magdalena Brzezińska, Nicolas Keller and Agnieszka M. Ruppert
Catalysts 2024, 14(2), 141; https://doi.org/10.3390/catal14020141 - 12 Feb 2024
Viewed by 1635
Abstract
The conversion of lignocellulosic biomass to valuable chemicals such as levulinic acid and γ-valerolactone is a promising approach for achieving a sustainable circular economy. However, the presence of impurities during the stepwise chemical processing chain of the biomass feedstock can significantly impact both [...] Read more.
The conversion of lignocellulosic biomass to valuable chemicals such as levulinic acid and γ-valerolactone is a promising approach for achieving a sustainable circular economy. However, the presence of impurities during the stepwise chemical processing chain of the biomass feedstock can significantly impact both the hydrolysis and hydrogenation steps implemented to convert the cellulosic feedstock to levulinic acid and further to γ-valerolactone, respectively. This review article explores the effects of those impurities by classifying them into two groups, namely endogenous and exogenous types, based on whether they originate directly from the raw lignocellulosic biomass or arise during its multi-step chemical processing. Endogenous impurities include heavy metals, alkali metals, alkaline earth metals, proteins, and side products from the downstream treatment of cellulose, while exogenous impurities are introduced during physical pre-treatments such as ball milling or during the hydrolysis step, or they might originate from the reactor setup. The specific catalyst deactivation by carbonaceous species such as humins and coke is considered. The mechanisms of impurity-induced catalyst deactivation and by-product formation are thoroughly discussed. Additionally, strategies for minimizing the detrimental effects of impurities on biomass conversion and enhancing catalytic efficiency and stability are also proposed. Full article
(This article belongs to the Section Biomass Catalysis)
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3 pages, 169 KiB  
Editorial
Gold, Silver and Copper Catalysis
by Sónia Alexandra Correia Carabineiro
Catalysts 2024, 14(2), 140; https://doi.org/10.3390/catal14020140 - 10 Feb 2024
Viewed by 1011
Abstract
In terms of catalysis, the exploration of novel materials and innovative methodologies continues to drive the field forward, offering solutions to pressing challenges in various industrial applications [...] Full article
(This article belongs to the Special Issue Gold, Silver and Copper Catalysis)
11 pages, 5920 KiB  
Article
The Regeneration of Dolomite as a Heterogeneous Catalyst for Biodiesel Production
by Rasa Šlinkšienė, Rasa Paleckienė, Ieva Gaidė, Violeta Makarevičienė and Eglė Sendžikienė
Catalysts 2024, 14(2), 139; https://doi.org/10.3390/catal14020139 - 10 Feb 2024
Viewed by 981
Abstract
Dolomite as a heterogeneous catalyst can be used in biodiesel synthesis. Process material costs can be reduced by regenerating and reusing the catalyst. Two methods of regeneration of dolomite were studied: (1) washing for 30 min with methanol, filtration, and washing for 30 [...] Read more.
Dolomite as a heterogeneous catalyst can be used in biodiesel synthesis. Process material costs can be reduced by regenerating and reusing the catalyst. Two methods of regeneration of dolomite were studied: (1) washing for 30 min with methanol, filtration, and washing for 30 min with hexane and (2) calcination at high temperature. Catalytic efficiency and catalyst changes after 1–6 cycles were evaluated. X-ray, FTIR, and SEM studies were performed. Calcination has been found to be a more effective method of catalyst regeneration than washing with solvents. The catalytic effectiveness of dolomite only slightly decreased over six application cycles. The results of the instrumental analysis showed that the structure and composition of the dolomite do not change during calcination after three cycles, while obvious changes in the structure of dolomite during catalyst washing were observed. Full article
(This article belongs to the Section Biomass Catalysis)
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14 pages, 3777 KiB  
Article
Regulating the Hydrodeoxygenation Activity of Molybdenum Carbide with Different Diamines as Carbon Sources
by Linyuan Zhou, Huiru Yang, Xiangze Du and Changwei Hu
Catalysts 2024, 14(2), 138; https://doi.org/10.3390/catal14020138 - 10 Feb 2024
Viewed by 1076
Abstract
The hydrodeoxygenation (HDO) of renewable fats or fatty acids into alkanes is a powerful measure to address energy and environmental crises. Molybdenum carbide-based catalysts are promising due to their platinum-like noble metal electronic properties. In this paper, Mo2C catalysts were prepared [...] Read more.
The hydrodeoxygenation (HDO) of renewable fats or fatty acids into alkanes is a powerful measure to address energy and environmental crises. Molybdenum carbide-based catalysts are promising due to their platinum-like noble metal electronic properties. In this paper, Mo2C catalysts were prepared by one-step carbonization of amine molybdenum oxide (AMO) precursors using diamines with different carbon chain lengths as ligands. The physical and chemical properties and the HDO catalytic activity of the catalysts were investigated. The results indicate that as the carbon chain of diamines in the precursor increases, the carbon content of the catalysts in the surface and bulk phase increases. The Mo2C-12 catalyst exhibited excellent catalytic performance, with a palmitic acid conversion rate of 100% and an alkane selectivity of 96.6%, which are attributed to the smallest particle size, largest pore size, and synergistic effect of carbon. This work provides a simple and safe method for regulating the surface properties of Mo2C catalysts. Full article
(This article belongs to the Section Environmental Catalysis)
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24 pages, 2405 KiB  
Review
Advanced Technologies Conciliating Desulfurization and Denitrogenation to Prepare Clean Fuels
by Rui G. Faria, Dinis Silva, Fátima Mirante, Sandra Gago, Luís Cunha-Silva and Salete S. Balula
Catalysts 2024, 14(2), 137; https://doi.org/10.3390/catal14020137 - 09 Feb 2024
Viewed by 1367
Abstract
The removal of sulfur- and nitrogen-containing compounds present in fuels is and will be crucial to accomplish actual strict regulations to avoid environmental and humanity health adversities. The conventional hydrodesulfurization and hydrodenitrogenation processes conducted by refineries are limited due to severe operating conditions, [...] Read more.
The removal of sulfur- and nitrogen-containing compounds present in fuels is and will be crucial to accomplish actual strict regulations to avoid environmental and humanity health adversities. The conventional hydrodesulfurization and hydrodenitrogenation processes conducted by refineries are limited due to severe operating conditions, and even more importantly, they are inefficient for simultaneously removing nitrogen- and sulfur-containing compounds in fuels. On the other hand, non-hydrogen technologies are beneficial in terms of mild operating conditions, and during the last two decades, some successful works have shown that these can be highly effective at efficiently removing both sulfur- and nitrogen-containing compounds from liquid fuels. For more than four decades, extensive research (thousands of publications since the 1980s) has been dedicated to developing remote desulfurization technologies without taking into consideration the presence of a complex fuel matrix, or even taking into account the presence of other harmful pollutant elements, such as nitrogen. Even more recently, several effective non-hydrogen denitrogenation processes have been reported without considering the presence of sulfur compounds. This review paper is a reflection on the limited work that has been successfully performed to simultaneously remove sulfur- and nitrogen-containing compounds from fuels. An evaluation of different methodologies (adsorption, extraction, oxidative (photo)catalysis, ultrasound-assisted oxidation) is presented here. Furthermore, this review intends to define new future strategies that will allow the design of more suitable and economical technologies, effectively conciliating desulfurization and denitrogenation processes to produce more sustainable fuels. Full article
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22 pages, 10846 KiB  
Article
Cobalt–Magnesium Oxide Catalysts for Deep Oxidation of Hydrocarbons
by Magira Zhylkybek, Bolatbek Khussain, Alexandr Sass, Ivan Torlopov, Tolkyn Baizhumanova, Svetlana Tungatarova, Alexandr Brodskiy, Galina Xanthopoulou, Kenzhegul Rakhmetova, Rabiga Sarsenova, Kaysar Kassymkan and Yermek Aubakirov
Catalysts 2024, 14(2), 136; https://doi.org/10.3390/catal14020136 - 09 Feb 2024
Viewed by 1032
Abstract
Co–Mg catalysts for methane combustion were synthesized and studied, revealing the transformation of MgCo2O4 spinel into a CoO–MgO solid solution with oxygen release from the spinel lattice as the calcination temperature increased. Repeated heat treatment of the calcined solid solution [...] Read more.
Co–Mg catalysts for methane combustion were synthesized and studied, revealing the transformation of MgCo2O4 spinel into a CoO–MgO solid solution with oxygen release from the spinel lattice as the calcination temperature increased. Repeated heat treatment of the calcined solid solution at lower temperatures led to spinel regeneration with segregation of the solid solution phase. A TPR of the samples showed the presence of two characteristic peaks, the first of which relates to the transition of Co3+Oh spinel to the Co2+Oh structure of CoO, and the second to the reduction of CoO to Co°. The second peak was observed at 540–620 °C for samples calcined at temperatures below spinel decomposition, and for high-temperature samples at 900–1100 °C. Taking into account the identity of the structure of phases obtained in both cases, the formation of not a true CoO–MgO solid solution, but rather a mixture of ordered oxides (“pseudo-solid solution”) in the low-temperature region, was postulated. A study of the activity of the samples showed the high activity of the spinel systems and a linear relationship between the activation energy of methane oxidation and the heat treatment temperature. Full article
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14 pages, 2639 KiB  
Article
Modification of SmMn2O5 Catalyst with Silver for Soot Oxidation: Ag Loading and Metal–Support Interactions
by Baofang Jin, Yuxin Liu, Yue Ma, Zhenguo Li, Kaixiang Li, Shuang Liu, Rui Ran and Xiaodong Wu
Catalysts 2024, 14(2), 135; https://doi.org/10.3390/catal14020135 - 09 Feb 2024
Viewed by 983
Abstract
A series of Ag-modified manganese-mullite (SmMn2O5) catalysts with different Ag contents (1, 3, and 6 wt.%) were prepared via a citric acid sol–gel method for catalytic soot oxidation. The catalysts were characterized by powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), [...] Read more.
A series of Ag-modified manganese-mullite (SmMn2O5) catalysts with different Ag contents (1, 3, and 6 wt.%) were prepared via a citric acid sol–gel method for catalytic soot oxidation. The catalysts were characterized by powder X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Raman spectroscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy analysis (HRTEM), X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). The soot oxidation activity of the mullite was significantly promoted by the addition of silver and affected by the loading amount of the metal. Herein, the influences of silver loading on the metal size distribution and its interactions with the mullite were studied. Based on these characterizations, a possible soot oxidation reaction mechanism was proposed for silver-modified SmMn2O5. Full article
(This article belongs to the Section Industrial Catalysis)
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0 pages, 3500 KiB  
Article
Catalytic Partial Oxidation of Methane to Methanol over Fe2O3/MWCNTs
by Zhengqing Zhou, Yinghua Zhang, Zhian Huang, Jia Liu, Jinguo Sang, Zuochun Luan, Wei Tian, Yukun Gao, Xingyu Zhang, Yucheng Ji and Tao Tang
Catalysts 2024, 14(2), 134; https://doi.org/10.3390/catal14020134 - 08 Feb 2024
Viewed by 916
Abstract
The catalytic partial oxidation of methane (CPOM) to methanol has been regarded as a promising approach for methane utilization, despite that the conversion remains a formidable challenge in the perspective of catalysts. A novel catalyst system of multi-wall carbon nanotubes (MWCNTs) that supported [...] Read more.
The catalytic partial oxidation of methane (CPOM) to methanol has been regarded as a promising approach for methane utilization, despite that the conversion remains a formidable challenge in the perspective of catalysts. A novel catalyst system of multi-wall carbon nanotubes (MWCNTs) that supported Fe2O3 with existing I2, consisting of non-noble metal and working in weak acid at an ambient temperature, was investigated for CPOM. MWCNTs supported the Fe2O3 catalyst, which was prepared by the impregnation method and characterized via HRTEM, XRD, XPS, FT-IR, and BET techniques. The characterization results reveal that, as a non-noble metal catalyst, the Fe2O3/MWCNTs catalyst had a good catalytic performance and stability in the CPOM. With the variation of reaction pressure and the dosage of Fe2O3/MWCNTs, the catalyst system obtained the highest methane conversion rate of 7.41% and methanol selectivity of 86.3%, which is analogous to that of the equivalently strong acid catalyst system. The I2-Fe2O3/MWCNTs catalyst system has great potential in the application of CPOM under mild, environmentally benign conditions, such as non-noble metal requirement, ambient temperature, and weak acid. The reaction mechanism was discussed. Full article
(This article belongs to the Section Environmental Catalysis)
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13 pages, 3365 KiB  
Article
Study on the Degradation Effect of Tetracycline Using a Co-Catalyst Loaded on Red Mud
by Yang Yue, Qu Wu, Chaofan Zheng, Yongjun Sun and Kinjal J. Shah
Catalysts 2024, 14(2), 133; https://doi.org/10.3390/catal14020133 - 08 Feb 2024
Viewed by 881
Abstract
Red mud was modified by impregnation with Co element loading. The Co-RM catalyst was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), and UV full-band scanning. The results showed that the modified Co-RM catalyst successfully loaded the Co [...] Read more.
Red mud was modified by impregnation with Co element loading. The Co-RM catalyst was characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray fluorescence (XRF), and UV full-band scanning. The results showed that the modified Co-RM catalyst successfully loaded the Co element and formed an irregular pore structure on the surface, thereby increasing the number of active sites of the red mud catalyst and effectively improving the degradation efficiency of tetracycline. Under the optimal conditions of a catalyst dosage of 0.3 g/L, a persulfate dosage of 3 g/L, a reaction temperature of 50 °C, and a pH value of 7, a removal rate of 50 mg/L of tetracycline can be achieved: 89.5% after 90 min. The effects of common anions and humic acids in water, as well as radical quenchers (anhydrous ethanol and tert-butanol), on the degradation of tetracycline were investigated. The results showed that Cl, CO32−, HCO3, H2PO4, NO32−, HPO42−, and humic acids showed inhibitory effects on the degradation of tetracycline, while SO42− showed a promoting effect on the degradation of tetracycline. The free radical quenching experiment showed that the most important free radicals that can degrade tetracycline in the system are sulfate radicals. Full article
(This article belongs to the Special Issue Heterogeneous Catalysts for Organic Wastewater Treatment)
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12 pages, 2760 KiB  
Article
Forming a Cu-Based Catalyst for Efficient Hydrogenation Conversion of Starch into Glucose
by Shenghua Zhu, Jue Li, Fuchang Cheng and Jinghua Liang
Catalysts 2024, 14(2), 132; https://doi.org/10.3390/catal14020132 - 08 Feb 2024
Viewed by 1095
Abstract
A pellet-forming as-catalyst, CuO/Al2O3, was prepared by the precipitation–tablet molding method and characterized by the Brunner–Emmet–Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) techniques and TEM. The characterization results showed that the formed [...] Read more.
A pellet-forming as-catalyst, CuO/Al2O3, was prepared by the precipitation–tablet molding method and characterized by the Brunner–Emmet–Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) techniques and TEM. The characterization results showed that the formed CuO/Al2O3 was in situ reduced to Cu/Al2O3 and Cu2O/ Al2O3 catalysts in the reaction system. The catalytic performance of catalyzing hydrogenation starch into glucose was investigated in an autoclave over CuO/Al2O3. The yield of glucose reached 83.16% at a temperature of 160 °C, a pressure of 1.8 MPa, a 100 g starch solution of 15 wt%, a catalyst dosage of 2.25%, a reaction time of 4 h, and a rotational speed of 630 r/min. The reusability of the catalyst was evaluated, and the glucose yield did not decrease obviously even after being reused for five consecutive cycles. Starch was converted into glucose through the synergistic action of Cu+ and Cu0 catalysis. This work is expected to provide valuable insights into the design of catalysts and the hydrogenation process for efficient starch hydrogenation. Full article
(This article belongs to the Section Catalytic Materials)
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16 pages, 7713 KiB  
Article
Improvement of NH3-SCR Performance by Exposing Different Active Components in a VCeMn/Ti Catalytic System
by Shifei Gu, Chengheng Huang, Xiaorong Han, Qiuju Qin, Donghai Mo, Chen Li, Yuhua You, Lihui Dong and Bin Li
Catalysts 2024, 14(2), 131; https://doi.org/10.3390/catal14020131 - 07 Feb 2024
Viewed by 835
Abstract
The physicochemical properties of active components play a key role in enhancing catalytic performance. In multi-component catalysts, different components offer a wide range of structural possibilities and catalytic potential. However, determining the role of specific components in enhancing efficiency may be blurry. This [...] Read more.
The physicochemical properties of active components play a key role in enhancing catalytic performance. In multi-component catalysts, different components offer a wide range of structural possibilities and catalytic potential. However, determining the role of specific components in enhancing efficiency may be blurry. This study synthetized a range of catalysts with various metal compositions on their external surfaces to investigate their catalytic activity on NH3-SCR. The V/CeMn/Ti catalysts exhibited exceptional catalytic efficiency and strong tolerance to SO2 during the SCR process. In the system, Mn and Ce facilitated electron transfer during the catalytic removal of NOx. As an assisting agent, increased the number of active species and acidic sites, playing a crucial role in oxidizing NO to NO2 and facilitating the denitrogenation reaction process at low temperatures. Further studies showed that the three ingredients exhibited unique adsorbent behaviors on the reacting gases, which provided different catalytic possibilities. This work modeled the particular catalysis of V and Ce (Mn) species, respectively, and offers experimental instruction for improving the activity and excellent tolerance to SO2 by controlling active ingredients. Full article
(This article belongs to the Special Issue Rare Earth Catalysis: From Synthesis to Sustainable Applications)
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12 pages, 6434 KiB  
Article
Regulating Lattice Oxygen on the Surfaces of Porous Single-Crystalline NiO for Stabilized and Enhanced CO Oxidation
by Xin Wen and Kui Xie
Catalysts 2024, 14(2), 130; https://doi.org/10.3390/catal14020130 - 07 Feb 2024
Viewed by 953
Abstract
The long-range ordered lattice structure and interconnected porous microstructure of porous single crystals (PSCs) provide structural regularity and connectivity in remote electron movement to stabilize oxygen vacancies and activate lattice oxygen linked to surface active sites. In this work, we prepare NiO powder, [...] Read more.
The long-range ordered lattice structure and interconnected porous microstructure of porous single crystals (PSCs) provide structural regularity and connectivity in remote electron movement to stabilize oxygen vacancies and activate lattice oxygen linked to surface active sites. In this work, we prepare NiO powder, single-crystal (SC) NiO, and PSC NiO. NiO contains a significant amount of oxygen vacancies. We find that the structure of porous NiO can create more oxygen vacancies. We load Pt onto these NiO crystals by atomic layer deposition (ALD) to activate lattice oxygen on definite NiO surfaces. The results show that Pt-loaded NiO effectively exhibits CO oxidation performance, in which Pt-loaded PSC NiO completely oxidizes CO at 65 °C. With 1% CO fully adsorbed, the density of activate lattice oxygen becomes an essential factor affecting performance. PSC NiO with deposited Pt clusters exhibited stable CO oxidation catalysis when run in air at ~65 °C for 300 h. Full article
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23 pages, 7253 KiB  
Article
Insight into the Catalytic Performance of a Zinc-Pillared Curcumin/Bentonite Composite for Enhanced Oxidation of Ibuprofen Residuals into Environmental Products: The Pathway and Toxicity
by Sarah I. Othman, Marwa H. Shemy, Haifa E. Alfassam, Haifa A. Alqhtani, Ahmed A. Allam, Mostafa R. Abukhadra and Stefano Bellucci
Catalysts 2024, 14(2), 129; https://doi.org/10.3390/catal14020129 - 07 Feb 2024
Viewed by 1068
Abstract
Environmental organo bentonite synthesis using curcumin-derived chemicals is used as catalyst support for zinc with a Zn-pillaring structure (Zn@CU/BEN). The obtained composite was assessed as an affordable, highly effective, and multifunctional photocatalyst for enhanced oxidation of ibuprofen (IBU) residuals in water supplies. The [...] Read more.
Environmental organo bentonite synthesis using curcumin-derived chemicals is used as catalyst support for zinc with a Zn-pillaring structure (Zn@CU/BEN). The obtained composite was assessed as an affordable, highly effective, and multifunctional photocatalyst for enhanced oxidation of ibuprofen (IBU) residuals in water supplies. The Zn@CU/BEN composite (0.4 g/L) displayed significant catalytic activities, resulting in the complete oxidation of IBU (25 mg/L) after 80 min. Then, the complete mineralization based on the full elimination of TOC content was recognized after 160 min, with significant indications about the formed intermediates. The identified intermediates, together with the identification of hydroxyl radicals as the essential oxidizing agent, declared an oxidation pathway of IBU over Zn@CU/BEN that involved three steps: hydroxylation, decarboxylation/demethylation, and ring-opening processes. The toxic properties of raw pollutants as well as the oxidizing product at different durations were assessed based on the cell viability results of kidney (HEK293T) and liver (HepG2) cell lines. The partially oxidized sample in the initial duration displayed a higher toxicity impact than the raw IBU. However, the treated sample after 160 min reflected high biosafety and non-toxic properties (cell viability > 97%). The synergetic impact of bentonite and bentonite organo-modified by curcumin extract reflects enhancements in the adsorption as well as the oxidation performance of pillared zinc as a catalyst. Full article
(This article belongs to the Topic Advanced Oxidation Processes for Wastewater Purification)
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4 pages, 168 KiB  
Editorial
Catalysis on Zeolites and Zeolite-like Materials
by Wladimir Reschetilowski
Catalysts 2024, 14(2), 128; https://doi.org/10.3390/catal14020128 - 07 Feb 2024
Viewed by 1013
Abstract
When the Swedish mineralogist Axel F [...] Full article
(This article belongs to the Special Issue Catalysis on Zeolites and Zeolite-Like Materials)
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