Gloribel Morales Hernández, José Escobar, J.G. Pacheco Sosa, Mario A. Guzmán Cruz, José G. Torres Torres, Paz del Ángel Vicente, M. Barrera, Carlos E. Santolalla Vargas, Hermicenda Pérez Vidal
Lanthanum (La) integration (at various nominal contents) in SBA-15 prepared under acidic medium was intended from corresponding direct nitrate addition during mesoporous silica formation. Materials were impregnated with Pt (1.5 wt%) and studied through several textural (N2 physisorption), structural (XRD, TG-DTG), and surface (FTIR, STEM-HAADF, SEM-EDS, NH3, and CO2 TPD) instrumental techniques. Pt-impregnated solids were tested in phenol hydrodeoxygenation (HDO, T = 250 °C, 3.2 MPa, batch reactor, n-decane as solvent). Catalytic activity (in pseudo-first-order kinetic constant, kHDO basis) was not directly related to Pt dispersion, which was not determined by nominal rare earth content. Determining the actual composition of modified SBA-15 materials is crucial in reaching sound conclusions regarding their physicochemical properties, especially when La modifier is directly added during mesoporous matrix formation, where efficient interaction among constituents could be difficult to get. Otherwise, results from some characterization techniques (N2 physisorption and FTIR, for instance) could be misleading and even contradictory. Indeed, extant modifier precursors, when under SBA-15 synthesis conditions, could affect the properties of prepared materials even though they were absent in obtained formulations. Performing simple compositional analysis could eliminate uncertainties regarding the role of various modifiers on characteristics of final catalysts. However, several groups have failed in doing so.
{"title":"La-Modified SBA-15 Prepared by Direct Synthesis: Importance of Determining Actual Composition","authors":"Gloribel Morales Hernández, José Escobar, J.G. Pacheco Sosa, Mario A. Guzmán Cruz, José G. Torres Torres, Paz del Ángel Vicente, M. Barrera, Carlos E. Santolalla Vargas, Hermicenda Pérez Vidal","doi":"10.3390/catal14070436","DOIUrl":"https://doi.org/10.3390/catal14070436","url":null,"abstract":"Lanthanum (La) integration (at various nominal contents) in SBA-15 prepared under acidic medium was intended from corresponding direct nitrate addition during mesoporous silica formation. Materials were impregnated with Pt (1.5 wt%) and studied through several textural (N2 physisorption), structural (XRD, TG-DTG), and surface (FTIR, STEM-HAADF, SEM-EDS, NH3, and CO2 TPD) instrumental techniques. Pt-impregnated solids were tested in phenol hydrodeoxygenation (HDO, T = 250 °C, 3.2 MPa, batch reactor, n-decane as solvent). Catalytic activity (in pseudo-first-order kinetic constant, kHDO basis) was not directly related to Pt dispersion, which was not determined by nominal rare earth content. Determining the actual composition of modified SBA-15 materials is crucial in reaching sound conclusions regarding their physicochemical properties, especially when La modifier is directly added during mesoporous matrix formation, where efficient interaction among constituents could be difficult to get. Otherwise, results from some characterization techniques (N2 physisorption and FTIR, for instance) could be misleading and even contradictory. Indeed, extant modifier precursors, when under SBA-15 synthesis conditions, could affect the properties of prepared materials even though they were absent in obtained formulations. Performing simple compositional analysis could eliminate uncertainties regarding the role of various modifiers on characteristics of final catalysts. However, several groups have failed in doing so.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141668467","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}
Elena Millán Ordóñez, Noelia Mota Toledo, Bertrand Revel, Olivier Lafon, R. N. Navarro Yerga
The performance of bifunctional hybrid catalysts based on phosphotungstic acid (H3PW12O40, HPW) supported on TiO2 combined with a Cu-ZnO(Al) catalyst in the direct synthesis of dimethyl ether (DME) from syngas has been investigated. In this work, different types of TiO2 were used as a support to study the effect of changes in the structure of the TiO2 support on the acidity and dispersion of HPW. Various TiO2 supports with different structural and surface characteristics have been studied and the results indicate that: (i) the crystallinity and crystallite size of the primary particles of the HPW units depend on the TiO2 support; (ii) the pore size distribution of the TiO2 support affects the surface segregation of the heteropolyacids; and (iii) changes in the supported HPW acid catalysts do not significantly alter the crystal structure of the CuO and ZnO phases after contact with CZA in bifunctional catalysts. The activity results indicate that the variation in the intrinsic activity of the Cu-ZnOx centers in the bifunctional catalysts for direct DME synthesis is minimal due to the limited alteration of the crystal structure of the centers.
{"title":"Effect of TiO2 on Acidity and Dispersion of H3PW12O40 in Bifunctional Cu-ZnO(Al)-H3PW12O40/TiO2 Catalysts for Direct Dimethyl Ether Synthesis","authors":"Elena Millán Ordóñez, Noelia Mota Toledo, Bertrand Revel, Olivier Lafon, R. N. Navarro Yerga","doi":"10.3390/catal14070435","DOIUrl":"https://doi.org/10.3390/catal14070435","url":null,"abstract":"The performance of bifunctional hybrid catalysts based on phosphotungstic acid (H3PW12O40, HPW) supported on TiO2 combined with a Cu-ZnO(Al) catalyst in the direct synthesis of dimethyl ether (DME) from syngas has been investigated. In this work, different types of TiO2 were used as a support to study the effect of changes in the structure of the TiO2 support on the acidity and dispersion of HPW. Various TiO2 supports with different structural and surface characteristics have been studied and the results indicate that: (i) the crystallinity and crystallite size of the primary particles of the HPW units depend on the TiO2 support; (ii) the pore size distribution of the TiO2 support affects the surface segregation of the heteropolyacids; and (iii) changes in the supported HPW acid catalysts do not significantly alter the crystal structure of the CuO and ZnO phases after contact with CZA in bifunctional catalysts. The activity results indicate that the variation in the intrinsic activity of the Cu-ZnOx centers in the bifunctional catalysts for direct DME synthesis is minimal due to the limited alteration of the crystal structure of the centers.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141668416","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}
In the face of escalating environmental challenges, innovative solutions for purifying air and water are more critical than ever [...]
面对不断升级的环境挑战，净化空气和水的创新解决方案比以往任何时候都更加重要 [...]
{"title":"Editorial: Air and Water Purification Processes through Photocatalysis—Scale-Up Perspectives, 2nd Edition","authors":"Maria Laura Tummino, R. N. Navarro Yerga","doi":"10.3390/catal14070434","DOIUrl":"https://doi.org/10.3390/catal14070434","url":null,"abstract":"In the face of escalating environmental challenges, innovative solutions for purifying air and water are more critical than ever [...]","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"104 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667053","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}
K. Kouvelis, Evangelia E. Karavaka, D. Panagiotaras, Dimitris Papoulis, Z. Frontistis, A. Petala
Developing highly active and available, environmentally friendly, and low-cost photocatalytic materials is one of the most popular topics in photocatalytic degradation systems. In the present study, a series of BiOCl/Sepiolite composite photocatalysts were prepared (in the range of 5%BiOCl/Sepiolite–30%BiOCl/Sepiolite). Their characterization was conducted using X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, nitrogen physical physisorption at the temperature of liquid nitrogen (77 K), and attenuated total reflectance-Fourier transform infrared spectroscopy. Results showed that composite photocatalysts possess superior efficiency than the parent materials for losartan, an antihypertensive agent, degradation in water, with the sample with only 10%wt. BiOCl shows the highest performance. The beneficial effect of the addition of sepiolite to BiOCl is derived from the increase in surface area, the prevention of particle aggregation, and the efficient separation of photogenerated species. Increasing catalyst concentration from 125 mg/L up to 500 mg/L was accompanied by an increase in the apparent kinetic constant from 0.077 min−1 to 0.197 min−1 while varying losartan concentration from 0.25 to 5.00 mg/L slowed down the removal efficiency. In addition, losartan degradation was only partially hampered in the case of bottled water, whereas it was practically stopped in a secondary wastewater effluent. Overall, this study serves as a useful guide for using geopolymers in photocatalytic applications.
{"title":"Photocatalytic Degradation of Losartan with BiOCl/Sepiolite Nanocomposites","authors":"K. Kouvelis, Evangelia E. Karavaka, D. Panagiotaras, Dimitris Papoulis, Z. Frontistis, A. Petala","doi":"10.3390/catal14070433","DOIUrl":"https://doi.org/10.3390/catal14070433","url":null,"abstract":"Developing highly active and available, environmentally friendly, and low-cost photocatalytic materials is one of the most popular topics in photocatalytic degradation systems. In the present study, a series of BiOCl/Sepiolite composite photocatalysts were prepared (in the range of 5%BiOCl/Sepiolite–30%BiOCl/Sepiolite). Their characterization was conducted using X-ray diffraction, diffuse reflectance spectroscopy, scanning electron microscopy, nitrogen physical physisorption at the temperature of liquid nitrogen (77 K), and attenuated total reflectance-Fourier transform infrared spectroscopy. Results showed that composite photocatalysts possess superior efficiency than the parent materials for losartan, an antihypertensive agent, degradation in water, with the sample with only 10%wt. BiOCl shows the highest performance. The beneficial effect of the addition of sepiolite to BiOCl is derived from the increase in surface area, the prevention of particle aggregation, and the efficient separation of photogenerated species. Increasing catalyst concentration from 125 mg/L up to 500 mg/L was accompanied by an increase in the apparent kinetic constant from 0.077 min−1 to 0.197 min−1 while varying losartan concentration from 0.25 to 5.00 mg/L slowed down the removal efficiency. In addition, losartan degradation was only partially hampered in the case of bottled water, whereas it was practically stopped in a secondary wastewater effluent. Overall, this study serves as a useful guide for using geopolymers in photocatalytic applications.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670193","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}
Simona Renda, J. Lasobras, J. Soler, J. Herguido, Miguel Menéndez
The fluidization of two different solids was investigated by varying the temperature and pressure conditions and the fluidizing gas. The solids are a novel catalyst and a water sorbent that could be used to perform sorption-enhanced methanol synthesis; the operating conditions were selected accordingly to this process. The aim of this investigation was to find an expression for predicting the minimum fluidization conditions of a methanol synthesis catalyst and an adsorbent in the presence of their process stream and operating conditions. The findings of this study highlighted how umf (STP) decreases with a rise in temperature and increases with a rise in pressure, according to other works in the literature with different solids. Furthermore, the type of gas was found to influence the minimum fluidization velocity significantly. The experimental results agreed well with a theoretical expression of the minimum fluidization velocity adjusted for temperature, pressure, and viscosity. The choice of the expression for viscosity calculation in the case of gas mixtures was found to be of key importance. These results will be useful for researchers aiming to calculate the minimum fluidization velocity of a catalyst or other solids under reaction conditions using results obtained at ambient conditions with air or inert gas.
{"title":"Dependence of the Fluidizing Condition on Operating Parameters for Sorption-Enhanced Methanol Synthesis Catalyst and Adsorbent","authors":"Simona Renda, J. Lasobras, J. Soler, J. Herguido, Miguel Menéndez","doi":"10.3390/catal14070432","DOIUrl":"https://doi.org/10.3390/catal14070432","url":null,"abstract":"The fluidization of two different solids was investigated by varying the temperature and pressure conditions and the fluidizing gas. The solids are a novel catalyst and a water sorbent that could be used to perform sorption-enhanced methanol synthesis; the operating conditions were selected accordingly to this process. The aim of this investigation was to find an expression for predicting the minimum fluidization conditions of a methanol synthesis catalyst and an adsorbent in the presence of their process stream and operating conditions. The findings of this study highlighted how umf (STP) decreases with a rise in temperature and increases with a rise in pressure, according to other works in the literature with different solids. Furthermore, the type of gas was found to influence the minimum fluidization velocity significantly. The experimental results agreed well with a theoretical expression of the minimum fluidization velocity adjusted for temperature, pressure, and viscosity. The choice of the expression for viscosity calculation in the case of gas mixtures was found to be of key importance. These results will be useful for researchers aiming to calculate the minimum fluidization velocity of a catalyst or other solids under reaction conditions using results obtained at ambient conditions with air or inert gas.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 37","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670349","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 interaction between point defects in (La1−xCax)MnO3−δ (x = 0, 0.2, 0.3, 0.4) perovskites and their redox catalytic properties in a three-reactor chemical looping hydrogen production process is investigated. During the reduction step with CH4, the behavior of the materials is extrinsically determined and strongly depends on the Ca content. At small oxygen deficiencies, CH4 becomes oxidized to CO2. As the deficiency increases, partial oxidation to CO and H2 at a molar ratio of approximately 2 is favored. During the water-splitting step, the dependency on the Ca content is much weaker since it is intrinsically determined by the Mn2+→Mn3+ oxidation with simultaneous annihilation of oxygen vacancies that are not required to compensate for the extra negative charge of the Ca dopant. Hydrogen productivities in the order of 13 cm3 (STP) H2/g solid could be achieved during the water-splitting step at 1000 °C. The materials exhibited reproducible catalytic behavior during 10 cycles of the complete three-step process and were found to retain their perovskite structure.
研究了 (La1-xCax)MnO3-δ (x = 0, 0.2, 0.3, 0.4) 包晶石中的点缺陷与其在三反应器化学循环制氢过程中的氧化还原催化特性之间的相互作用。在与 CH4 的还原过程中，材料的行为是由外在决定的，并与 Ca 的含量密切相关。在缺氧较小时，CH4 会被氧化成 CO2。随着缺氧程度的增加，部分氧化成 CO 和 H2 的摩尔比约为 2。在分水步骤中，对 Ca 含量的依赖性要弱得多，因为它本质上是由 Mn2+→Mn3+ 氧化和氧空位同时湮灭决定的，而氧空位不需要补偿 Ca 掺杂剂的额外负电荷。在 1000 °C 的分水步骤中，氢气生产率可达到 13 cm3（STP）H2/g 固体的数量级。在完整的三步过程的 10 个循环中，这些材料表现出了可重复的催化行为，并保持了它们的包晶结构。
{"title":"(La1−xCax)MnO3−δ (x = 0, 0.2, 0.3, 0.4) Perovskites as Redox Catalysts in Chemical Looping Hydrogen Production Process: The Relation between Defect Chemistry and Redox Performance","authors":"Moschos Moschos, A. Evdou, Vassilios Zaspalis","doi":"10.3390/catal14070431","DOIUrl":"https://doi.org/10.3390/catal14070431","url":null,"abstract":"The interaction between point defects in (La1−xCax)MnO3−δ (x = 0, 0.2, 0.3, 0.4) perovskites and their redox catalytic properties in a three-reactor chemical looping hydrogen production process is investigated. During the reduction step with CH4, the behavior of the materials is extrinsically determined and strongly depends on the Ca content. At small oxygen deficiencies, CH4 becomes oxidized to CO2. As the deficiency increases, partial oxidation to CO and H2 at a molar ratio of approximately 2 is favored. During the water-splitting step, the dependency on the Ca content is much weaker since it is intrinsically determined by the Mn2+→Mn3+ oxidation with simultaneous annihilation of oxygen vacancies that are not required to compensate for the extra negative charge of the Ca dopant. Hydrogen productivities in the order of 13 cm3 (STP) H2/g solid could be achieved during the water-splitting step at 1000 °C. The materials exhibited reproducible catalytic behavior during 10 cycles of the complete three-step process and were found to retain their perovskite structure.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141671536","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}
Tetrahydrofurfuryl alcohol, a cost-effective biomass derivative, offers a sustainable path for synthesizing 1,5-pentanediol through hydrogenolysis. To develop the efficient production of 1,5-pentanediol from this alcohol, we have prepared a series of MgAl2O4-modified Pt/WOx/γ-Al2O3 catalysts with varying compositions via impregnation–calcination methods. The physicochemical properties of these catalysts were subsequently characterized using diverse techniques. Characterization revealed that magnesia–alumina spinel modification enhanced Pt particle dispersion, CO adsorption on Pt/WOx/γ-Al2O3, reduced Pt particle reduction temperature, diminished the acid content in the catalysts, and increased the surface oxygen vacancy concentration. These alterations appear to influence the catalyst performance, though other factors cannot be ruled out. Catalytic activity tests demonstrated that magnesia–alumina spinel modification improved tetrahydrofurfuryl alcohol hydrogenolysis activity and the 1,5-pentanediol selectivity of Pt/WOx/γ-Al2O3. Optimal performance was achieved at 12% magnesia–alumina spinel loading, with a tetrahydrofurfuryl alcohol conversion of 47.3% and 1,5-pentanediol selectivity of 88.4%.
{"title":"Selective Hydrogenolysis of Tetrahydrofurfuryl Alcohol to 1,5-Pentanediol over MgAl2O4-Modified Pt/WO3/γ-Al2O3 Catalyst","authors":"Weiying Wang, Changlin Chen","doi":"10.3390/catal14070428","DOIUrl":"https://doi.org/10.3390/catal14070428","url":null,"abstract":"Tetrahydrofurfuryl alcohol, a cost-effective biomass derivative, offers a sustainable path for synthesizing 1,5-pentanediol through hydrogenolysis. To develop the efficient production of 1,5-pentanediol from this alcohol, we have prepared a series of MgAl2O4-modified Pt/WOx/γ-Al2O3 catalysts with varying compositions via impregnation–calcination methods. The physicochemical properties of these catalysts were subsequently characterized using diverse techniques. Characterization revealed that magnesia–alumina spinel modification enhanced Pt particle dispersion, CO adsorption on Pt/WOx/γ-Al2O3, reduced Pt particle reduction temperature, diminished the acid content in the catalysts, and increased the surface oxygen vacancy concentration. These alterations appear to influence the catalyst performance, though other factors cannot be ruled out. Catalytic activity tests demonstrated that magnesia–alumina spinel modification improved tetrahydrofurfuryl alcohol hydrogenolysis activity and the 1,5-pentanediol selectivity of Pt/WOx/γ-Al2O3. Optimal performance was achieved at 12% magnesia–alumina spinel loading, with a tetrahydrofurfuryl alcohol conversion of 47.3% and 1,5-pentanediol selectivity of 88.4%.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":"174 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141674182","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}
Hydrogen peroxide (H2O2) is one of the most environmentally friendly and versatile chemical oxidizing agents, with only O2 and H2O as reaction products. It is widely used in environmental protection, industrial production, and medical fields. At present, most of the industrial production of H2O2 adopts anthraquinone oxidation, but there are shortcomings such as pollution of the environment and large energy consumption. Covalent organic frameworks (COFs) are a class of porous crystalline materials formed by organic molecular building blocks connected by covalent bonds. The ordered conjugated structure of COFs not only facilitates the absorption of light energy but also promotes the transport of excited-state electrons. Therefore, the photochemical synthesis of H2O2 from water and oxygen using photocatalysts based on COFs as a green route has attracted much attention. In this review, we provide an overview of recent studies on COFs as photocatalysts and the different mechanisms involved in the photocatalytic production of hydrogen peroxide. Then, we summarize the various strategies to improve the performance. Finally, we outline the challenges and future directions of COFs in practical applications. This review highlights the potential and application prospects of COFs in the photochemical synthesis of H2O2, aiming to provide guidance for the design of COF-based catalysts and the optimization for photocatalytic production of H2O2, in order to promote scientific development and application in this field.
{"title":"Photocatalytic Production of Hydrogen Peroxide from Covalent-Organic-Framework-Based Materials: A Mini-Review","authors":"Jiayi Meng, Yamei Huang, Xing-Zhi Wang, Yifan Liao, Huihui Zhang, Wei-Lin Dai","doi":"10.3390/catal14070429","DOIUrl":"https://doi.org/10.3390/catal14070429","url":null,"abstract":"Hydrogen peroxide (H2O2) is one of the most environmentally friendly and versatile chemical oxidizing agents, with only O2 and H2O as reaction products. It is widely used in environmental protection, industrial production, and medical fields. At present, most of the industrial production of H2O2 adopts anthraquinone oxidation, but there are shortcomings such as pollution of the environment and large energy consumption. Covalent organic frameworks (COFs) are a class of porous crystalline materials formed by organic molecular building blocks connected by covalent bonds. The ordered conjugated structure of COFs not only facilitates the absorption of light energy but also promotes the transport of excited-state electrons. Therefore, the photochemical synthesis of H2O2 from water and oxygen using photocatalysts based on COFs as a green route has attracted much attention. In this review, we provide an overview of recent studies on COFs as photocatalysts and the different mechanisms involved in the photocatalytic production of hydrogen peroxide. Then, we summarize the various strategies to improve the performance. Finally, we outline the challenges and future directions of COFs in practical applications. This review highlights the potential and application prospects of COFs in the photochemical synthesis of H2O2, aiming to provide guidance for the design of COF-based catalysts and the optimization for photocatalytic production of H2O2, in order to promote scientific development and application in this field.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141675046","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}
M. Nazir, A. Rehman, T. Najam, M. Elsadek, M. A. Ali, Ismail Hossain, Muhammad Khurram Tufail, Syed Shoaib Ahmad Shah
In this study, copper (Cu)- and manganese (Mn)-based layered double hydroxide (LDH) nanosheets were produced by modest and low-cost hydrothermal technique to display an improved photocatalytic performance toward the degradation of aqueous methylene blue (MB). The morphological and structural properties of the as-prepared photocatalysts were characterized through various techniques comprising XRD, FT-IR, SEM, EDS, and their MB degradation activity was evaluated under visible light irradiation. SEM results explore that the synthesized LDH materials have a sheet-like morphology and are stacked layer by layer. Various analysis parameters, such as the effect of the contact time, concentration and pH of MB solutions were performed to optimize the performance of fabricated LDH materials. The results revealed that the as-synthesized CuAl-LDH and MnAl-LDH exhibited a 74.95 and 70.93% removal of MB under solar light within 180 min. Moreover, synthesized photocatalysts showed an excellent performance of up to four regeneration cycles. We believe that this study provides novel mechanistic insights into the design and preparation of highly competent photocatalysts using low-cost materials, with applications in environmental remediation.
{"title":"Copper- and Manganese-Based Bimetallic Layered Double Hydroxides for Catalytic Reduction of Methylene Blue","authors":"M. Nazir, A. Rehman, T. Najam, M. Elsadek, M. A. Ali, Ismail Hossain, Muhammad Khurram Tufail, Syed Shoaib Ahmad Shah","doi":"10.3390/catal14070430","DOIUrl":"https://doi.org/10.3390/catal14070430","url":null,"abstract":"In this study, copper (Cu)- and manganese (Mn)-based layered double hydroxide (LDH) nanosheets were produced by modest and low-cost hydrothermal technique to display an improved photocatalytic performance toward the degradation of aqueous methylene blue (MB). The morphological and structural properties of the as-prepared photocatalysts were characterized through various techniques comprising XRD, FT-IR, SEM, EDS, and their MB degradation activity was evaluated under visible light irradiation. SEM results explore that the synthesized LDH materials have a sheet-like morphology and are stacked layer by layer. Various analysis parameters, such as the effect of the contact time, concentration and pH of MB solutions were performed to optimize the performance of fabricated LDH materials. The results revealed that the as-synthesized CuAl-LDH and MnAl-LDH exhibited a 74.95 and 70.93% removal of MB under solar light within 180 min. Moreover, synthesized photocatalysts showed an excellent performance of up to four regeneration cycles. We believe that this study provides novel mechanistic insights into the design and preparation of highly competent photocatalysts using low-cost materials, with applications in environmental remediation.","PeriodicalId":505577,"journal":{"name":"Catalysts","volume":" 46","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141676667","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}
Amr Fouda, Mohammed Ali Abdel-Rahman, A. Eid, S. Selim, H. Ejaz, Muharib Alruwaili, Emad Manni, Muhammad S. Almuhayawi, Soad K. Al Jaouni, S. Hassan
In the current investigation, the antibacterial activity of zinc oxide nanoparticles (ZnO-NPs) formed by an aqueous extract of Psidium guajava leaves against foodborne pathogenic bacterial strains was investigated. To achieve this goal, 33 bacterial isolates were obtained from spoiled fruits. Among these isolates, 79% showed cellulase activity, 82% showed amylase activity, 81% exhibited xylanase potential, and 65% exhibited lipase activity. Moreover, 12 isolates showed complete hemolysis (β-hemolysis). The identification of these isolates was done using sequencing and amplification of 16s rRNA as Staphylococcus aureus (two strains), Pseudomonas syringae (one strain), E. coli (two strains), Salmonella typhimurium (two strains), Listeria monocytogenes (one isolate), Bacillus cereus (two isolates), and Bacillus subtilis (two isolates). The formed ZnO-NPs by aqueous Psidium guajava leaf extract were characterized using UV, FT-IR, TEM, EDX, XRD, DLS, and Zeta potential. The data revealed the successful formation of a spherical shape, crystallographic structure, and well-arranged ZnO-NPs. FT-IR showed the effect of different functional groups in the plant extract in the formation of ZnO-NPs through reducing, capping, and stabilizing of end products. Moreover, EDX analysis showed that the Zn ion occupied the main component of the produced NPs. Interestingly, the obtained bacterial strains showed varied sensitivity toward green-synthesized ZnO-NPs. The growth inhibition of foodborne pathogenic strains by ZnO-NPs was concentration dependent, forming a zone of inhibition in the range of 20–23 mm at a concentration of 200 µg mL−1, which decreased to 15–18 mm at 100 µg mL−1. Moreover, the values of MIC were 25 and 50 µg mL−1 based on the bacterial strain. Overall, the green-synthesized ZnO-NPs can be a useful approach for inhibiting the growth of spoilage bacterial strains that destroy fruits and hence reduce the harmful effects of traditional treatment methods on the environment and human health.
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