Mohammed Sifat, Eugene Shin, Anthony Schevon, Hugo Ramos, Amol Pophali, Hye-Jung Jung, Gary Halada, Yizhi Meng, N. Olynik, D. Sprouster, Taejin Kim
Crystal violet (CV) is an organic chloride salt and a triphenylmethane dye commonly used in the textile processing industry, also being used as a disinfectant and a biomedical stain. Although CV is widely used, it is carcinogenic to humans and is retained by industrial-produced effluent for an extended period. The different types of metal oxide (MOx) have impressive photocatalytic properties, allowing them to be utilized for pollutant degradation. The role of the photocatalyst is to facilitate oxidation and reduction processes by trapping light energy. In this study, we investigated different types of metal oxides, such as titanium dioxide (TiO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), iron (III) oxide (Fe2O3), copper (II) oxide (CuO), copper (I) oxide (Cu2O), and niobium pentoxide (Nb2O5) for the CV decomposition reaction at ambient conditions. For characterization, BET and Raman spectroscopy were applied, providing findings showing that the surface area of the anatase TiO2 and ZnO were 5 m2/g and 12.1 m2/g, respectively. The activity tests over TiO2 and ZnO catalysts revealed that up to ~98% of the dye could be decomposed under UV irradiation in <2 h. The decomposition of CV is directly influenced by various factors, such as the types of MOx, the band gap–water splitting relationship, and the recombination rate of electron holes.
{"title":"Photocatalytic Degradation of Crystal Violet (CV) Dye over Metal Oxide (MOx) Catalysts","authors":"Mohammed Sifat, Eugene Shin, Anthony Schevon, Hugo Ramos, Amol Pophali, Hye-Jung Jung, Gary Halada, Yizhi Meng, N. Olynik, D. Sprouster, Taejin Kim","doi":"10.3390/catal14060377","DOIUrl":"https://doi.org/10.3390/catal14060377","url":null,"abstract":"Crystal violet (CV) is an organic chloride salt and a triphenylmethane dye commonly used in the textile processing industry, also being used as a disinfectant and a biomedical stain. Although CV is widely used, it is carcinogenic to humans and is retained by industrial-produced effluent for an extended period. The different types of metal oxide (MOx) have impressive photocatalytic properties, allowing them to be utilized for pollutant degradation. The role of the photocatalyst is to facilitate oxidation and reduction processes by trapping light energy. In this study, we investigated different types of metal oxides, such as titanium dioxide (TiO2), zinc oxide (ZnO), zirconium dioxide (ZrO2), iron (III) oxide (Fe2O3), copper (II) oxide (CuO), copper (I) oxide (Cu2O), and niobium pentoxide (Nb2O5) for the CV decomposition reaction at ambient conditions. For characterization, BET and Raman spectroscopy were applied, providing findings showing that the surface area of the anatase TiO2 and ZnO were 5 m2/g and 12.1 m2/g, respectively. The activity tests over TiO2 and ZnO catalysts revealed that up to ~98% of the dye could be decomposed under UV irradiation in <2 h. The decomposition of CV is directly influenced by various factors, such as the types of MOx, the band gap–water splitting relationship, and the recombination rate of electron holes.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"24 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141342909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The removal of pesticides and other organic pollutants from water through advanced oxidation processes (AOPs) holds great promise. The main advantage of these technologies is that they remove, or at least reduce, pesticide levels by mineralization rather than transfer, as in conventional processes. This study first evaluated the effectiveness of UV/S2O8= compared to heterogeneous photocatalysis using UV/TiO2 processes on the degradation of two commonly used herbicides (terbuthylazine and isoproturon) in aqueous solutions using a laboratory photoreactor. In addition, the effect of the UV wavelength on the degradation efficiency of both herbicides was investigated. Although the degradation rate was greater under UV(254)/S2O8= nm than under UV(365)/S2O8= nm, complete degradation of the herbicides (0.2 mg L−1) was achieved within 30 min under UV-366 nm using a Na2S2O8 dose of 250 mg L−1 in the absence of inorganic anions. To assess the impact of the water matrix, the individual and combined effects of sulfate (SO4=), bicarbonate (HCO3−), and chloride (Cl−) were evaluated. These can react with hydroxyl (HO•) and sulfate (SO4•−) radicals generated during AOPs to form new radicals with a lower redox potential. The results showed negligible effects of SO4=, while the combination of HCO3− and Cl− seemed to be the key to the decrease in herbicide removal efficiency found when working with complex matrices. Finally, the main intermediates detected during the photodegradation process are identified, and the likely pathways involving dealkylation, dechlorination, and hydroxylation are proposed and discussed.
{"title":"Impact of Inorganic Anions on the Photodegradation of Herbicide Residues in Water by UV/Persulfate-Based Advanced Oxidation","authors":"G. Pérez-Lucas, Aitor Campillo, Simón Navarro","doi":"10.3390/catal14060376","DOIUrl":"https://doi.org/10.3390/catal14060376","url":null,"abstract":"The removal of pesticides and other organic pollutants from water through advanced oxidation processes (AOPs) holds great promise. The main advantage of these technologies is that they remove, or at least reduce, pesticide levels by mineralization rather than transfer, as in conventional processes. This study first evaluated the effectiveness of UV/S2O8= compared to heterogeneous photocatalysis using UV/TiO2 processes on the degradation of two commonly used herbicides (terbuthylazine and isoproturon) in aqueous solutions using a laboratory photoreactor. In addition, the effect of the UV wavelength on the degradation efficiency of both herbicides was investigated. Although the degradation rate was greater under UV(254)/S2O8= nm than under UV(365)/S2O8= nm, complete degradation of the herbicides (0.2 mg L−1) was achieved within 30 min under UV-366 nm using a Na2S2O8 dose of 250 mg L−1 in the absence of inorganic anions. To assess the impact of the water matrix, the individual and combined effects of sulfate (SO4=), bicarbonate (HCO3−), and chloride (Cl−) were evaluated. These can react with hydroxyl (HO•) and sulfate (SO4•−) radicals generated during AOPs to form new radicals with a lower redox potential. The results showed negligible effects of SO4=, while the combination of HCO3− and Cl− seemed to be the key to the decrease in herbicide removal efficiency found when working with complex matrices. Finally, the main intermediates detected during the photodegradation process are identified, and the likely pathways involving dealkylation, dechlorination, and hydroxylation are proposed and discussed.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141348557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junling Zhan, Chongyao Bi, Xiaohui Du, Tao Liu, Mingjun Jia
Rationally controlling the morphology and microstructure of the zeolite crystals could play a significant role in optimizing their physicochemical properties and catalytic performances for application in various zeolite-based heterogeneous catalysis processes. Among different controlling strategies, the utilization of zeolite growth modifiers (ZGMs), which are molecules capable of altering the anisotropic rates of crystal growth, is becoming a promising approach to modulate the morphology and microstructural characteristics of zeolite crystals. In this mini-review, we attempt to provide an organized overview of the recent progress in the usage of several easily available polymer-based growth modifiers in the synthesis of some commonly used microporous zeolites and to reveal their roles in controlling the morphology and various physicochemical properties of zeolite crystals during hydrothermal synthesis processes. This review is expected to provide some guidance for deeply understanding the modulation mechanisms of polymer-based zeolite growth modifiers and for appropriately utilizing such a modulation strategy to achieve precise control of the morphology and microstructure of zeolite crystals that display optimal performance in the target catalytic reactions.
{"title":"Morphology and Microstructural Optimization of Zeolite Crystals Utilizing Polymer Growth Modifiers for Enhanced Catalytic Application","authors":"Junling Zhan, Chongyao Bi, Xiaohui Du, Tao Liu, Mingjun Jia","doi":"10.3390/catal14060375","DOIUrl":"https://doi.org/10.3390/catal14060375","url":null,"abstract":"Rationally controlling the morphology and microstructure of the zeolite crystals could play a significant role in optimizing their physicochemical properties and catalytic performances for application in various zeolite-based heterogeneous catalysis processes. Among different controlling strategies, the utilization of zeolite growth modifiers (ZGMs), which are molecules capable of altering the anisotropic rates of crystal growth, is becoming a promising approach to modulate the morphology and microstructural characteristics of zeolite crystals. In this mini-review, we attempt to provide an organized overview of the recent progress in the usage of several easily available polymer-based growth modifiers in the synthesis of some commonly used microporous zeolites and to reveal their roles in controlling the morphology and various physicochemical properties of zeolite crystals during hydrothermal synthesis processes. This review is expected to provide some guidance for deeply understanding the modulation mechanisms of polymer-based zeolite growth modifiers and for appropriately utilizing such a modulation strategy to achieve precise control of the morphology and microstructure of zeolite crystals that display optimal performance in the target catalytic reactions.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"23 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141354668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingli Li, He Cui, Yi Zhao, Shunli Li, Jiabo Wang, Kai Ge, Yongfang Yang
Photocatalytic technology, which is regarded as a green route to transform solar energy into chemical fuels, plays an important role in the fields of energy and environmental protection. An emerging S-scheme heterojunction with the tightly coupled interface, whose photocatalytic efficiency exceeds those of conventional type II and Z-scheme photocatalysts, has received much attention due to its rapid charge carrier separation and strong redox capacity. This review provides a systematic description of S-scheme heterojunction in the photocatalysis, including its development, reaction mechanisms, preparation, and characterization methods. In addition, S-scheme photocatalysts for CO2 reduction are described in detail by categorizing them as 0D/1D, 0D/2D, 0D/3D, 2D/2D, and 2D/3D. Finally, some defects of S-scheme heterojunctions are pointed out, and the future development of S-scheme heterojunctions is proposed.
光催化技术被视为将太阳能转化为化学燃料的绿色途径，在能源和环境保护领域发挥着重要作用。一种新兴的具有紧密耦合界面的 S 型结构异质结，其光催化效率超过了传统的 II 型和 Z 型光催化剂，因其快速的电荷载流子分离和强大的氧化还原能力而备受关注。本综述系统阐述了光催化中的 S 型梯度异质结，包括其发展、反应机理、制备和表征方法。此外，还详细介绍了用于还原二氧化碳的 S 型光催化剂，将其分为 0D/1D、0D/2D、0D/3D、2D/2D 和 2D/3D。最后，指出了 S 型异质结的一些缺陷，并提出了 S 型异质结的未来发展方向。
{"title":"S-Scheme Heterojunction Photocatalysts for CO2 Reduction","authors":"Mingli Li, He Cui, Yi Zhao, Shunli Li, Jiabo Wang, Kai Ge, Yongfang Yang","doi":"10.3390/catal14060374","DOIUrl":"https://doi.org/10.3390/catal14060374","url":null,"abstract":"Photocatalytic technology, which is regarded as a green route to transform solar energy into chemical fuels, plays an important role in the fields of energy and environmental protection. An emerging S-scheme heterojunction with the tightly coupled interface, whose photocatalytic efficiency exceeds those of conventional type II and Z-scheme photocatalysts, has received much attention due to its rapid charge carrier separation and strong redox capacity. This review provides a systematic description of S-scheme heterojunction in the photocatalysis, including its development, reaction mechanisms, preparation, and characterization methods. In addition, S-scheme photocatalysts for CO2 reduction are described in detail by categorizing them as 0D/1D, 0D/2D, 0D/3D, 2D/2D, and 2D/3D. Finally, some defects of S-scheme heterojunctions are pointed out, and the future development of S-scheme heterojunctions is proposed.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"77 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141352932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as an effective solution to reduce Pt consumption while further promoting their performance, making them promising for various electrocatalytic reactions. This review summarizes the latest advances in PtCu-based alloy catalysts over the past several years from both synthetic and applied perspectives. In the synthesis section, the selection of support and reagents, synthesis routes, as well as post-treatment methods at high temperatures are reviewed. The application section focuses not only on newly proposed electrochemical reactions such as nitrogen-related reactions and O2 reduction but also extends to device-level applications. The discussion in this review aims to provide further insights and guidance for the development of PtCu electrocatalysts for practical applications.
{"title":"Recent Advances of PtCu Alloy in Electrocatalysis: Innovations and Applications","authors":"Ziyang Shen, Jinyao Tang, Xiaochen Shen","doi":"10.3390/catal14060373","DOIUrl":"https://doi.org/10.3390/catal14060373","url":null,"abstract":"Developing highly active and durable platinum-based catalysts is crucial for electrochemical renewable energy conversion technologies but the limited supply and high cost of platinum have hindered their widespread implementation. The incorporation of non-noble metals, particularly copper, into Pt catalysts has been demonstrated as an effective solution to reduce Pt consumption while further promoting their performance, making them promising for various electrocatalytic reactions. This review summarizes the latest advances in PtCu-based alloy catalysts over the past several years from both synthetic and applied perspectives. In the synthesis section, the selection of support and reagents, synthesis routes, as well as post-treatment methods at high temperatures are reviewed. The application section focuses not only on newly proposed electrochemical reactions such as nitrogen-related reactions and O2 reduction but also extends to device-level applications. The discussion in this review aims to provide further insights and guidance for the development of PtCu electrocatalysts for practical applications.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"48 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141358992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lutf Ullah, Sehrish Munsif, Long Cao, Jing-Cai Zhang, Wei-Zhen Li
Catalytic combustion of volatile organic compounds (VOCs) usually requires external energy input to hold the desired reaction temperature via electric heating. This work presents an example of internal onsite heating of the catalytic active sites via hydrogen catalytic combustion with air over a conventional Pd/Al2O3 catalyst. Hydrogen combustion was ignited by the catalyst at room temperature without electric heating, and thus the temperatures were readily varied with the concentrations of H2. Representative oxygenated VOCs such as methanol, formaldehyde and formic acid can be completely oxidized into CO2 and water by co-feeding with H2 below its low explosion limit of 4% using Pd/Al2O3 as shared catalyst. The catalytic performance apparently is not sensitive to the sizes of Pd nanoparticles in fresh and spent states, as revealed by XRD and STEM. This provides an option for using renewable green hydrogen to eliminate VOC pollutants in an energy-efficient way.
{"title":"Facile Abatement of Oxygenated Volatile Organic Compounds via Hydrogen Co-Combustion over Pd/Al2O3 Catalyst as Onsite Heating Source","authors":"Lutf Ullah, Sehrish Munsif, Long Cao, Jing-Cai Zhang, Wei-Zhen Li","doi":"10.3390/catal14060372","DOIUrl":"https://doi.org/10.3390/catal14060372","url":null,"abstract":"Catalytic combustion of volatile organic compounds (VOCs) usually requires external energy input to hold the desired reaction temperature via electric heating. This work presents an example of internal onsite heating of the catalytic active sites via hydrogen catalytic combustion with air over a conventional Pd/Al2O3 catalyst. Hydrogen combustion was ignited by the catalyst at room temperature without electric heating, and thus the temperatures were readily varied with the concentrations of H2. Representative oxygenated VOCs such as methanol, formaldehyde and formic acid can be completely oxidized into CO2 and water by co-feeding with H2 below its low explosion limit of 4% using Pd/Al2O3 as shared catalyst. The catalytic performance apparently is not sensitive to the sizes of Pd nanoparticles in fresh and spent states, as revealed by XRD and STEM. This provides an option for using renewable green hydrogen to eliminate VOC pollutants in an energy-efficient way.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"1 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141363307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. A. Durante-Salmerón, Isabel Fraile-Gutiérrez, Rubén Gil-Gonzalo, N. Acosta, I. Aranaz, Andrés R. Alcántara
Chitin and chitosan, abundant biopolymers derived from the shells of crustaceans and the cell walls of fungi, have garnered considerable attention in pharmaceutical circles due to their biocompatibility, biodegradability, and versatile properties. Deep eutectic solvents (DESs), emerging green solvents composed of eutectic mixtures of hydrogen bond acceptors and donors, offer promising avenues for enhancing the solubility and functionality of chitin and chitosan in pharmaceutical formulations. This review delves into the potential of utilizing DESs as solvents for chitin and chitosan, highlighting their efficiency in dissolving these polymers, which facilitates the production of novel drug delivery systems, wound dressings, tissue engineering scaffolds, and antimicrobial agents. The distinctive physicochemical properties of DESs, including low toxicity, low volatility, and adaptable solvation power, enable the customization of chitin and chitosan-based materials to meet specific pharmaceutical requirements. Moreover, the environmentally friendly nature of DESs aligns with the growing demand for sustainable and eco-friendly processes in pharmaceutical manufacturing. This revision underscores recent advances illustrating the promising role of DESs in evolving the pharmaceutical applications of chitin and chitosan, laying the groundwork for the development of innovative drug delivery systems and biomedical materials with enhanced efficacy and safety profiles.
甲壳素和壳聚糖是从甲壳类动物的外壳和真菌的细胞壁中提取的丰富生物聚合物，由于其生物相容性、生物可降解性和多功能性，在医药界引起了广泛关注。深共晶溶剂（DES）是由氢键受体和供体的共晶混合物组成的新兴绿色溶剂，为提高甲壳素和壳聚糖在药物制剂中的溶解性和功能性提供了广阔的前景。本综述深入探讨了利用 DES 作为甲壳素和壳聚糖溶剂的潜力，强调了 DES 在溶解这些聚合物方面的效率，这有助于生产新型给药系统、伤口敷料、组织工程支架和抗菌剂。DES 具有独特的理化特性，包括低毒性、低挥发性和适应性强的溶解能力，可定制甲壳素和壳聚糖基材料，以满足特定的制药要求。此外，DES 的环保特性符合制药行业对可持续发展和环保工艺日益增长的需求。本修订版强调了最近的研究进展，说明DES在甲壳素和壳聚糖制药应用的发展中具有广阔的前景，为开发具有更高的疗效和安全性的创新型给药系统和生物医学材料奠定了基础。
{"title":"Strategies to Prepare Chitin and Chitosan-Based Bioactive Structures Aided by Deep Eutectic Solvents: A Review","authors":"D. A. Durante-Salmerón, Isabel Fraile-Gutiérrez, Rubén Gil-Gonzalo, N. Acosta, I. Aranaz, Andrés R. Alcántara","doi":"10.3390/catal14060371","DOIUrl":"https://doi.org/10.3390/catal14060371","url":null,"abstract":"Chitin and chitosan, abundant biopolymers derived from the shells of crustaceans and the cell walls of fungi, have garnered considerable attention in pharmaceutical circles due to their biocompatibility, biodegradability, and versatile properties. Deep eutectic solvents (DESs), emerging green solvents composed of eutectic mixtures of hydrogen bond acceptors and donors, offer promising avenues for enhancing the solubility and functionality of chitin and chitosan in pharmaceutical formulations. This review delves into the potential of utilizing DESs as solvents for chitin and chitosan, highlighting their efficiency in dissolving these polymers, which facilitates the production of novel drug delivery systems, wound dressings, tissue engineering scaffolds, and antimicrobial agents. The distinctive physicochemical properties of DESs, including low toxicity, low volatility, and adaptable solvation power, enable the customization of chitin and chitosan-based materials to meet specific pharmaceutical requirements. Moreover, the environmentally friendly nature of DESs aligns with the growing demand for sustainable and eco-friendly processes in pharmaceutical manufacturing. This revision underscores recent advances illustrating the promising role of DESs in evolving the pharmaceutical applications of chitin and chitosan, laying the groundwork for the development of innovative drug delivery systems and biomedical materials with enhanced efficacy and safety profiles.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141366043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingqiao Xing, Ning Liu, Chengna Dai, Biaohua Chen
CO2 oxidative dehydrogenation of propane (CO2-ODHP), being not only favorable for olefin production but also beneficial for CO2 emission control, has recently attracted great attention. Here, a series of single metal (Cr) and bimetal (Zr, La, Fe) modified ZSM-5 zeolites were prepared via an impregnation method. It was found that the bimetal modified ZSM-5 possessed much higher C3H8 and CO2 conversion than that of monometallic modified Cr3%-ZSM-5 (Cr3%-Z5), especially for Cr3%Zr2%-ZSM-5 (Cr3%Zr2%-Z5), which displayed the highest activity (65.4%) and olefin yield (1.65 × 103 μmol·gcat−1 h−1). Various characterizations were performed, including XRD, N2 adsorption-desorption, H2-TPR, Raman, XPS, HAAD-STEM, and TEM. It was revealed that Zr not only favored an improvement in the redox ability of Cr, but also contributed to the surface dispersion of loaded Cr species, constituting two major reasons explaining the superior activity of Cr3%Zr2%-Z5. To further improve CO2-ODHP catalytic behavior, a series of Cr3%-ZSM-5@SBA-15-n composite zeolite catalysts with diverse (ZSM-5/SBA-15) mass ratios were prepared (Cr3%-ZS-n, n = 0.5, 2, 6, 16), which screened out an optimum mass ratio of six. Based on this, the Cr3%Zr2%-ZS-6 compound was further prepared, and it eventually achieved even higher CO2-ODHP activity (76.9%) and olefin yield (1.72 × 103 μmol·gcat−1 h−1). Finally, the CO2-ODHP reaction mechanism was further investigated using in situ FTIR, and it was found that the reaction followed the Mars–van Krevelen mechanism, wherein CO2 participated in the reaction through generation of polydentate carbonates. The Cr6+ constituted as the active site, which was reduced to Cr3+ after the dihydrogen reaction, and was then further oxidized into Cr6+ by CO2, forming polydentate carbonates, and thus cycling the reactive species Cr6+. Additionally, assisted by a Brönsted acid site (favoring breaking of the C-C bond), C2H4 and CH4 were produced.
{"title":"CO2 Oxidative Dehydrogenation of Propane to Olefin over Cr-M (M = Zr, La, Fe) Based Zeolite Catalyst","authors":"Mingqiao Xing, Ning Liu, Chengna Dai, Biaohua Chen","doi":"10.3390/catal14060370","DOIUrl":"https://doi.org/10.3390/catal14060370","url":null,"abstract":"CO2 oxidative dehydrogenation of propane (CO2-ODHP), being not only favorable for olefin production but also beneficial for CO2 emission control, has recently attracted great attention. Here, a series of single metal (Cr) and bimetal (Zr, La, Fe) modified ZSM-5 zeolites were prepared via an impregnation method. It was found that the bimetal modified ZSM-5 possessed much higher C3H8 and CO2 conversion than that of monometallic modified Cr3%-ZSM-5 (Cr3%-Z5), especially for Cr3%Zr2%-ZSM-5 (Cr3%Zr2%-Z5), which displayed the highest activity (65.4%) and olefin yield (1.65 × 103 μmol·gcat−1 h−1). Various characterizations were performed, including XRD, N2 adsorption-desorption, H2-TPR, Raman, XPS, HAAD-STEM, and TEM. It was revealed that Zr not only favored an improvement in the redox ability of Cr, but also contributed to the surface dispersion of loaded Cr species, constituting two major reasons explaining the superior activity of Cr3%Zr2%-Z5. To further improve CO2-ODHP catalytic behavior, a series of Cr3%-ZSM-5@SBA-15-n composite zeolite catalysts with diverse (ZSM-5/SBA-15) mass ratios were prepared (Cr3%-ZS-n, n = 0.5, 2, 6, 16), which screened out an optimum mass ratio of six. Based on this, the Cr3%Zr2%-ZS-6 compound was further prepared, and it eventually achieved even higher CO2-ODHP activity (76.9%) and olefin yield (1.72 × 103 μmol·gcat−1 h−1). Finally, the CO2-ODHP reaction mechanism was further investigated using in situ FTIR, and it was found that the reaction followed the Mars–van Krevelen mechanism, wherein CO2 participated in the reaction through generation of polydentate carbonates. The Cr6+ constituted as the active site, which was reduced to Cr3+ after the dihydrogen reaction, and was then further oxidized into Cr6+ by CO2, forming polydentate carbonates, and thus cycling the reactive species Cr6+. Additionally, assisted by a Brönsted acid site (favoring breaking of the C-C bond), C2H4 and CH4 were produced.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141373411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rajeh Alotaibi, M. Amer, P. Arunachalam, Saad G. Alshammari
Using green synthetic methods, a manganese-cobalt oxyhydroxide (MnCo-OOH) nanocomposite for electrocatalysis was prepared. Electrocatalysts were examined using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FESEM). In an alkaline medium, cyclic voltammetry and chronoamperometric analysis were applied to assess the electrocatalytic features of the MnCo-OOH nanocomposite. A strong correlation existed between MnCo-OOH’s morphology, crystallinity, and electrochemical activity. Upon examining the electrochemical characteristics, the as-deposited MnCo-OOH catalyst demonstrated a significantly lower overpotential, achieving 75 mA·cm−2 OER current density at 370 mV, four times larger than 19.7 mA·cm−2 for CoOOH catalysts, signifying that the MnCo-OOH catalyst exhibits a higher electrocatalytic OER features. In addition, the MnCo-OOH nanocomposite demonstrated a high current density of 30 and 65 mA·cm−2 at 1.55 and 1.60 VRHE for 12 h in 1.0 M KOH aqueous electrolyte. As a result of this study, it was determined that the fabricated MnCo-OOH nanocomposite would be an appropriate electrocatalyst in water electrolysis.
{"title":"Green Synthesis of Manganese-Cobalt Oxyhydroxide Nanocomposite as Electrocatalyst for Enhanced Oxygen Evolution Reaction in Alkaline Medium","authors":"Rajeh Alotaibi, M. Amer, P. Arunachalam, Saad G. Alshammari","doi":"10.3390/catal14060369","DOIUrl":"https://doi.org/10.3390/catal14060369","url":null,"abstract":"Using green synthetic methods, a manganese-cobalt oxyhydroxide (MnCo-OOH) nanocomposite for electrocatalysis was prepared. Electrocatalysts were examined using powder X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), and field-emission scanning electron microscopy (FESEM). In an alkaline medium, cyclic voltammetry and chronoamperometric analysis were applied to assess the electrocatalytic features of the MnCo-OOH nanocomposite. A strong correlation existed between MnCo-OOH’s morphology, crystallinity, and electrochemical activity. Upon examining the electrochemical characteristics, the as-deposited MnCo-OOH catalyst demonstrated a significantly lower overpotential, achieving 75 mA·cm−2 OER current density at 370 mV, four times larger than 19.7 mA·cm−2 for CoOOH catalysts, signifying that the MnCo-OOH catalyst exhibits a higher electrocatalytic OER features. In addition, the MnCo-OOH nanocomposite demonstrated a high current density of 30 and 65 mA·cm−2 at 1.55 and 1.60 VRHE for 12 h in 1.0 M KOH aqueous electrolyte. As a result of this study, it was determined that the fabricated MnCo-OOH nanocomposite would be an appropriate electrocatalyst in water electrolysis.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"85 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141378217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the intensification of global resource shortages and the environmental crisis, hydrogen energy has garnered significant attention as a renewable and clean energy source. Water splitting is considered the most promising method of hydrogen production due to its non-polluting nature and high hydrogen concentration. However, the slow kinetics of the two key reactions, the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER), have greatly limited the development of related technologies. Meanwhile, the scarcity and high cost of precious metal catalysts represented by Pt and Ir/RuO2 limit their large-scale commercial application. Thus, it is essential to develop catalysts based on Earth’s transition metals that have abundant reserves. Vanadium (V) is an early transition metal with a distinct electronic structure from late transition metals such as Fe, Co, and Ni, which has been emphasized and studied by researchers. Numerous vanadium-based electrocatalysts have been developed for the HER and OER. In this review, the mechanisms of the HER and OER are described. Then, the compositions, properties, and modification strategies of various vanadium-based electrocatalysts are summarized, which include vanadium-based oxides, hydroxides, dichalcogenides, phosphides, nitrides, carbides, and vanadate. Finally, potential challenges and future perspectives are presented based on the current status of V-based electrocatalysts for water splitting.
随着全球资源短缺和环境危机的加剧，氢能作为一种可再生清洁能源备受关注。水分裂因其无污染和高氢气浓度而被认为是最有前途的制氢方法。然而，氢进化反应（HER）和氧进化反应（OER）这两个关键反应的缓慢动力学极大地限制了相关技术的发展。同时，以 Pt 和 Ir/RuO2 为代表的贵金属催化剂的稀缺性和高成本也限制了其大规模商业应用。因此，开发基于地球上储量丰富的过渡金属的催化剂至关重要。钒（V）是一种早期过渡金属，其电子结构与铁、钴和镍等晚期过渡金属截然不同，一直受到研究人员的重视和研究。针对 HER 和 OER 开发了许多钒基电催化剂。本综述首先介绍了 HER 和 OER 的机理。然后，总结了各种钒基电催化剂的组成、性质和改性策略，包括钒基氧化物、氢氧化物、二钙化物、磷化物、氮化物、碳化物和钒酸盐。最后，根据钒基电催化剂在水分离方面的现状，介绍了潜在的挑战和未来的展望。
{"title":"Recent Advances in Vanadium-Based Electrocatalysts for Hydrogen and Oxygen Evolution Reactions: A Review","authors":"Haoyu Li, Juan Wu, Mengyao Li, Yude Wang","doi":"10.3390/catal14060368","DOIUrl":"https://doi.org/10.3390/catal14060368","url":null,"abstract":"With the intensification of global resource shortages and the environmental crisis, hydrogen energy has garnered significant attention as a renewable and clean energy source. Water splitting is considered the most promising method of hydrogen production due to its non-polluting nature and high hydrogen concentration. However, the slow kinetics of the two key reactions, the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER), have greatly limited the development of related technologies. Meanwhile, the scarcity and high cost of precious metal catalysts represented by Pt and Ir/RuO2 limit their large-scale commercial application. Thus, it is essential to develop catalysts based on Earth’s transition metals that have abundant reserves. Vanadium (V) is an early transition metal with a distinct electronic structure from late transition metals such as Fe, Co, and Ni, which has been emphasized and studied by researchers. Numerous vanadium-based electrocatalysts have been developed for the HER and OER. In this review, the mechanisms of the HER and OER are described. Then, the compositions, properties, and modification strategies of various vanadium-based electrocatalysts are summarized, which include vanadium-based oxides, hydroxides, dichalcogenides, phosphides, nitrides, carbides, and vanadate. Finally, potential challenges and future perspectives are presented based on the current status of V-based electrocatalysts for water splitting.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"46 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141385872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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