A series of Zn salts were used as catalysts for the reaction of glycerol and urea to produce glycerol carbonate and it was found that ZnSO4 showed the highest catalytic activity. Furthermore, the effects of reaction parameters on the glycerol conversion and glycerol carbonate yield were studied in detail. The results indicated that the glycerol conversion and glycerol carbonate yield were increased with the reaction temperature, reaction time, and catalyst amount while the optimal reaction conditions were 140 °C, 240 min, catalyst amount of 5 wt% (based on the glycerol weight), and urea-to-glycerol molar ratio of 1.1:1. During the reaction, the ZnSO4 catalyst is transformed into Zn(NH3)2SO4 at the initial stage of the reaction and then further transformed into Zn(C3H6O3). Zn(C3H6O3) and (NH4)2SO4 may be the true active species for the activation of urea and glycerol, respectively. The reaction mechanism is proposed in this article. Based on the experimental results, a reaction kinetics model considering the change in volume of the reaction system was also established, and the model parameters were obtained by fitting the experimental data. The statistical results showed that the established kinetics model is accurate.
{"title":"Reaction Kinetics and Mechanism for the Synthesis of Glycerol Carbonate from Glycerol and Urea Using ZnSO4 as a Catalyst","authors":"Huajun Wang, Jingjing Ma","doi":"10.3390/catal14010041","DOIUrl":"https://doi.org/10.3390/catal14010041","url":null,"abstract":"A series of Zn salts were used as catalysts for the reaction of glycerol and urea to produce glycerol carbonate and it was found that ZnSO4 showed the highest catalytic activity. Furthermore, the effects of reaction parameters on the glycerol conversion and glycerol carbonate yield were studied in detail. The results indicated that the glycerol conversion and glycerol carbonate yield were increased with the reaction temperature, reaction time, and catalyst amount while the optimal reaction conditions were 140 °C, 240 min, catalyst amount of 5 wt% (based on the glycerol weight), and urea-to-glycerol molar ratio of 1.1:1. During the reaction, the ZnSO4 catalyst is transformed into Zn(NH3)2SO4 at the initial stage of the reaction and then further transformed into Zn(C3H6O3). Zn(C3H6O3) and (NH4)2SO4 may be the true active species for the activation of urea and glycerol, respectively. The reaction mechanism is proposed in this article. Based on the experimental results, a reaction kinetics model considering the change in volume of the reaction system was also established, and the model parameters were obtained by fitting the experimental data. The statistical results showed that the established kinetics model is accurate.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"51 11","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139449455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Yousaf Arshad, Anam Suhail Ahmad, Jakub Mularski, Aleksandra Modzelewska, M. Jackowski, H. Pawlak-Kruczek, Lukasz Niedzwiecki
The advancement of plasma technology is intricately linked with the utilization of computational fluid dynamics (CFD) models, which play a pivotal role in the design and optimization of industrial-scale plasma reactors. This comprehensive compilation encapsulates the evolving landscape of plasma reactor design, encompassing fluid dynamics, chemical kinetics, heat transfer, and radiation energy. By employing diverse tools such as FLUENT, Python, MATLAB, and Abaqus, CFD techniques unravel the complexities of turbulence, multiphase flow, and species transport. The spectrum of plasma behavior equations, including ion and electron densities, electric fields, and recombination reactions, is presented in a holistic manner. The modeling of non-thermal plasma reactors, underpinned by precise mathematical formulations and computational strategies, is further empowered by the integration of machine learning algorithms for predictive modeling and optimization. From biomass gasification to intricate chemical reactions, this work underscores the versatile potential of plasma hybrid modeling in reshaping various industrial processes. Within the sphere of plasma catalysis, modeling and simulation methodologies have paved the way for transformative progress. Encompassing reactor configurations, kinetic pathways, hydrogen production, waste valorization, and beyond, this compilation offers a panoramic view of the multifaceted dimensions of plasma catalysis. Microkinetic modeling and catalyst design emerge as focal points for optimizing CO2 conversion, while the intricate interplay between plasma and catalysts illuminates insights into ammonia synthesis, methane reforming, and hydrocarbon conversion. Leveraging neural networks and advanced modeling techniques enables predictive prowess in the optimization of plasma-catalytic processes. The integration of plasma and catalysts for diverse applications, from waste valorization to syngas production and direct CO2/CH4 conversion, exemplifies the wide-reaching potential of plasma catalysis in sustainable practices. Ultimately, this anthology underscores the transformative influence of modeling and simulation in shaping the forefront of plasma-catalytic processes, fostering innovation and sustainable applications.
{"title":"Pioneering the Future: A Trailblazing Review of the Fusion of Computational Fluid Dynamics and Machine Learning Revolutionizing Plasma Catalysis and Non-Thermal Plasma Reactor Design","authors":"Muhammad Yousaf Arshad, Anam Suhail Ahmad, Jakub Mularski, Aleksandra Modzelewska, M. Jackowski, H. Pawlak-Kruczek, Lukasz Niedzwiecki","doi":"10.3390/catal14010040","DOIUrl":"https://doi.org/10.3390/catal14010040","url":null,"abstract":"The advancement of plasma technology is intricately linked with the utilization of computational fluid dynamics (CFD) models, which play a pivotal role in the design and optimization of industrial-scale plasma reactors. This comprehensive compilation encapsulates the evolving landscape of plasma reactor design, encompassing fluid dynamics, chemical kinetics, heat transfer, and radiation energy. By employing diverse tools such as FLUENT, Python, MATLAB, and Abaqus, CFD techniques unravel the complexities of turbulence, multiphase flow, and species transport. The spectrum of plasma behavior equations, including ion and electron densities, electric fields, and recombination reactions, is presented in a holistic manner. The modeling of non-thermal plasma reactors, underpinned by precise mathematical formulations and computational strategies, is further empowered by the integration of machine learning algorithms for predictive modeling and optimization. From biomass gasification to intricate chemical reactions, this work underscores the versatile potential of plasma hybrid modeling in reshaping various industrial processes. Within the sphere of plasma catalysis, modeling and simulation methodologies have paved the way for transformative progress. Encompassing reactor configurations, kinetic pathways, hydrogen production, waste valorization, and beyond, this compilation offers a panoramic view of the multifaceted dimensions of plasma catalysis. Microkinetic modeling and catalyst design emerge as focal points for optimizing CO2 conversion, while the intricate interplay between plasma and catalysts illuminates insights into ammonia synthesis, methane reforming, and hydrocarbon conversion. Leveraging neural networks and advanced modeling techniques enables predictive prowess in the optimization of plasma-catalytic processes. The integration of plasma and catalysts for diverse applications, from waste valorization to syngas production and direct CO2/CH4 conversion, exemplifies the wide-reaching potential of plasma catalysis in sustainable practices. Ultimately, this anthology underscores the transformative influence of modeling and simulation in shaping the forefront of plasma-catalytic processes, fostering innovation and sustainable applications.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"49 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139449597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The morphology of catalysts in microchannels plays a crucial role in the orbital maneuvering and networking applications of micro/nano satellites using hydrogen peroxide as a unit propellant. In this paper, a microfluidic reaction chip was designed and fabricated to detect the reaction rate of the catalytic decomposition of hydrogen peroxide solution by a microchannel catalytic bed. In addition, a silver thin film prepared by constant-current electroplating was used as a substrate for the microchannel catalyst. The results show that the ratio of surface area to area of silver film and the average particle size of silver particles have a significant positive correlation on the reaction rate of catalytic decomposition, while the thickness, silver content, and surface roughness of the silver film have no significant effect on the reaction rate of catalytic decomposition. The catalytic performance of the microchannel catalytic bed of silver thin film is greatly influenced by the conditions of electroplating, namely, the electroplating temperature (T), time (t), and current (I). And when I = 0.3 mA, t = 180 s, and T = 60 °C, the microchannel catalytic bed of the silver film prepared by electroplating reaches the optimal reaction rate for the catalytic decomposition of hydrogen peroxide solution. This study has the best process parameters for the design and optimization of heterogeneous catalysts applied to microfluidic reactors.
{"title":"Structure and Microchannel Catalytic Bed Performance of Silver Thin Films Prepared by Electroplating","authors":"Yong Yang, Y. Ye, Rui-qi Shen","doi":"10.3390/catal14010039","DOIUrl":"https://doi.org/10.3390/catal14010039","url":null,"abstract":"The morphology of catalysts in microchannels plays a crucial role in the orbital maneuvering and networking applications of micro/nano satellites using hydrogen peroxide as a unit propellant. In this paper, a microfluidic reaction chip was designed and fabricated to detect the reaction rate of the catalytic decomposition of hydrogen peroxide solution by a microchannel catalytic bed. In addition, a silver thin film prepared by constant-current electroplating was used as a substrate for the microchannel catalyst. The results show that the ratio of surface area to area of silver film and the average particle size of silver particles have a significant positive correlation on the reaction rate of catalytic decomposition, while the thickness, silver content, and surface roughness of the silver film have no significant effect on the reaction rate of catalytic decomposition. The catalytic performance of the microchannel catalytic bed of silver thin film is greatly influenced by the conditions of electroplating, namely, the electroplating temperature (T), time (t), and current (I). And when I = 0.3 mA, t = 180 s, and T = 60 °C, the microchannel catalytic bed of the silver film prepared by electroplating reaches the optimal reaction rate for the catalytic decomposition of hydrogen peroxide solution. This study has the best process parameters for the design and optimization of heterogeneous catalysts applied to microfluidic reactors.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"36 14","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Niloofar Mohammadpour, H. Kierzkowska‐Pawlak, J. Balcerzak, P. Uznański, J. Tyczkowski
Addressing the challenges associated with the highly exothermic nature of CO2 methanation, there is considerable interest in innovative catalyst designs on structural metallic supports. One promising solution in this regard involves thin films containing cobalt oxide within a carbon matrix, fabricated using the cold plasma deposition method (PECVD). The objective of this study was to search for a relationship between the molecular structure, nanostructure, and electronic structure of such films and their catalytic activity. The investigations employed various techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), X-ray diffraction (XRD), UV-VIS absorption, and catalytic tests in the CO2 methanation process. Three types of films were tested: untreated as-deposited (ad-CoO), thermally post-treated (TT-CoO), and argon plasma post-treated (PT-CoO) films. Among these, TT-CoO exhibited the most favorable catalytic properties, demonstrating a CO2 conversion rate of 83%, CH4 selectivity of 98% at 400 °C, and stability during the catalytic process. This superior performance was attributed to the formation of nanoscale heterojunctions in the TT-CoO film, where p-type CoO nanocrystallites interacted with the n-type carbon matrix. This work provides compelling evidence highlighting the key role of nanoscale heterojunctions in shaping the properties of nanocatalysts in thermal catalysis. These findings suggest promising prospects for designing new catalytic systems by manipulating interactions at the nanoscale.
为了应对二氧化碳甲烷化的高放热性所带来的挑战，人们对金属结构支撑物上的创新催化剂设计产生了浓厚的兴趣。这方面一个很有前景的解决方案是使用冷等离子体沉积法（PECVD）在碳基质中制造含有氧化钴的薄膜。本研究的目的是寻找此类薄膜的分子结构、纳米结构和电子结构与其催化活性之间的关系。研究采用了多种技术，包括 X 射线光电子能谱 (XPS)、紫外光电子能谱 (UPS)、X 射线衍射 (XRD)、紫外可见吸收以及二氧化碳甲烷化过程中的催化测试。测试了三种类型的薄膜：未经处理的沉积薄膜（ad-CoO）、热后处理薄膜（TT-CoO）和氩等离子体后处理薄膜（PT-CoO）。其中，TT-CoO 表现出最有利的催化特性，二氧化碳转化率达到 83%，400 °C 时的甲烷选择性达到 98%，并且在催化过程中保持稳定。这种优异的性能归功于 TT-CoO 薄膜中形成的纳米级异质结，其中 p 型 CoO 纳米晶与 n 型碳基质相互作用。这项工作提供了令人信服的证据，凸显了纳米级异质结在热催化中塑造纳米催化剂特性的关键作用。这些发现为通过操纵纳米尺度的相互作用来设计新型催化系统提供了广阔的前景。
{"title":"Plasma-Deposited CoO–(Carbon Matrix) Thin-Film Nanocatalysts: The Impact of Nanoscale p-n Heterojunctions on Activity in CO2 Methanation","authors":"Niloofar Mohammadpour, H. Kierzkowska‐Pawlak, J. Balcerzak, P. Uznański, J. Tyczkowski","doi":"10.3390/catal14010038","DOIUrl":"https://doi.org/10.3390/catal14010038","url":null,"abstract":"Addressing the challenges associated with the highly exothermic nature of CO2 methanation, there is considerable interest in innovative catalyst designs on structural metallic supports. One promising solution in this regard involves thin films containing cobalt oxide within a carbon matrix, fabricated using the cold plasma deposition method (PECVD). The objective of this study was to search for a relationship between the molecular structure, nanostructure, and electronic structure of such films and their catalytic activity. The investigations employed various techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), X-ray diffraction (XRD), UV-VIS absorption, and catalytic tests in the CO2 methanation process. Three types of films were tested: untreated as-deposited (ad-CoO), thermally post-treated (TT-CoO), and argon plasma post-treated (PT-CoO) films. Among these, TT-CoO exhibited the most favorable catalytic properties, demonstrating a CO2 conversion rate of 83%, CH4 selectivity of 98% at 400 °C, and stability during the catalytic process. This superior performance was attributed to the formation of nanoscale heterojunctions in the TT-CoO film, where p-type CoO nanocrystallites interacted with the n-type carbon matrix. This work provides compelling evidence highlighting the key role of nanoscale heterojunctions in shaping the properties of nanocatalysts in thermal catalysis. These findings suggest promising prospects for designing new catalytic systems by manipulating interactions at the nanoscale.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"52 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min Zheng, Xiangzhou Li, Dulin Yin, Steven R. Kirk, Hui Li, Peng Zhou, Yanhong Yang
Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW.
{"title":"Ammonium Phosphotungstate Bonded on Imidazolized Activated Carbon for Selective Catalytic Rearrangement of α-Epoxypinane to Carveol","authors":"Min Zheng, Xiangzhou Li, Dulin Yin, Steven R. Kirk, Hui Li, Peng Zhou, Yanhong Yang","doi":"10.3390/catal14010036","DOIUrl":"https://doi.org/10.3390/catal14010036","url":null,"abstract":"Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"30 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chenxuan Zhu, M. Guo, Ziqi Wang, Jiang He, Jiaqi Qiu, Yuxuan Guo, Yunfei Yan, Jingyu Ran, Zhongqing Yang
Carbon nitride MXene exhibits good metal conductivity, high photothermal conversion, carrier mobility, and high exposure of active sites, which makes it a promising co-catalyst for photothermal synergistic transformation of CO2. In this paper, Ti3CN/TiO2 heterojunction was constructed in situ using Ti3CN as TiO2 precursor to investigate the performance of Ti3CN MXene in photothermal synergistic transformation of CO2, and then the monolayer structure was utilized to enhance the interfacial charge transfer and improve the photothermal catalytic activity of Ti3CN. The catalysts were characterized by SEM, XRD, XPS, and UV-Vis DRS, and it was found the heterojunction constructed by monolayer MXene had a narrower bandgap and a higher carrier generation mobility, which, combined with the catalytic activity test, proved the single monolayer Ti3CN MXene had better photothermal synergistic conversion efficiency of CO2, and the heterojunction yield was 11.36 μmol·g−1·h−1 after layering, compared with that before layering (9.41%), which was 1.2 times higher than that before layering (9.41 μmol·g−1·h−1).
{"title":"Enhancement of Carrier Migration by Monolayer MXene Structure in Ti3CN/TiO2 Heterojunction to Achieve Efficient Photothermal Synergistic Transformation of CO2","authors":"Chenxuan Zhu, M. Guo, Ziqi Wang, Jiang He, Jiaqi Qiu, Yuxuan Guo, Yunfei Yan, Jingyu Ran, Zhongqing Yang","doi":"10.3390/catal14010035","DOIUrl":"https://doi.org/10.3390/catal14010035","url":null,"abstract":"Carbon nitride MXene exhibits good metal conductivity, high photothermal conversion, carrier mobility, and high exposure of active sites, which makes it a promising co-catalyst for photothermal synergistic transformation of CO2. In this paper, Ti3CN/TiO2 heterojunction was constructed in situ using Ti3CN as TiO2 precursor to investigate the performance of Ti3CN MXene in photothermal synergistic transformation of CO2, and then the monolayer structure was utilized to enhance the interfacial charge transfer and improve the photothermal catalytic activity of Ti3CN. The catalysts were characterized by SEM, XRD, XPS, and UV-Vis DRS, and it was found the heterojunction constructed by monolayer MXene had a narrower bandgap and a higher carrier generation mobility, which, combined with the catalytic activity test, proved the single monolayer Ti3CN MXene had better photothermal synergistic conversion efficiency of CO2, and the heterojunction yield was 11.36 μmol·g−1·h−1 after layering, compared with that before layering (9.41%), which was 1.2 times higher than that before layering (9.41 μmol·g−1·h−1).","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"32 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139389760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Surface geometry at the atomic level is an important factor related to the activity of a catalytic site. It is important to identify sites with high activity to comprehend the performance of a given catalyst. In this work, it is proposed that the optimal surface for a given reaction step should satisfy the condition ∂E∂xi|TS=0, where E is the transition state energy and xi is any variable characterizing the surface. Taking three elementary steps as examples, it is shown that the optimal site found by this method has significantly reduced TS (transition state) energy compared with facets commonly applied in previous studies, and, thus, it can be several orders more active. The method provides an insight into the geometric impact of catalysis, gives a blueprint for an ideal catalyst surface structure, and, thus, provides guidance for catalyst development.
原子层面的表面几何形状是影响催化位点活性的一个重要因素。要了解特定催化剂的性能，识别高活性位点非常重要。本研究提出，特定反应步骤的最佳表面应满足条件 ∂E∂xi|TS=0，其中 E 是过渡态能量，xi 是表征表面的任何变量。以三个基本步骤为例，研究表明，与以往研究中常用的面相比，用这种方法找到的最佳点的 TS（过渡态）能量大大降低，因此其活性可以提高几个数量级。该方法深入揭示了催化的几何影响，提供了理想催化剂表面结构的蓝图，从而为催化剂开发提供了指导。
{"title":"Ideal Site Geometry for Heterogeneous Catalytic Reactions: A DFT Study","authors":"Runcong Liu","doi":"10.3390/catal14010034","DOIUrl":"https://doi.org/10.3390/catal14010034","url":null,"abstract":"Surface geometry at the atomic level is an important factor related to the activity of a catalytic site. It is important to identify sites with high activity to comprehend the performance of a given catalyst. In this work, it is proposed that the optimal surface for a given reaction step should satisfy the condition ∂E∂xi|TS=0, where E is the transition state energy and xi is any variable characterizing the surface. Taking three elementary steps as examples, it is shown that the optimal site found by this method has significantly reduced TS (transition state) energy compared with facets commonly applied in previous studies, and, thus, it can be several orders more active. The method provides an insight into the geometric impact of catalysis, gives a blueprint for an ideal catalyst surface structure, and, thus, provides guidance for catalyst development.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":" 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139140603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmad M. Alghamdi, A. Ibrahim, Fekri Abdulraqeb Ahmed Ali, Nouf A. Bamatraf, A. Fakeeha, Ahmed I. Osman, S. Alreshaidan, Farid Fadhillah, S. Al‐Zahrani, Ahmed S. Al-Fatesh
This study examines nickel catalysts on two different supports—magnesium oxide (MgO) and modified MgO (with 10 wt.% MOx; M = Ti, Zr, Al)—for their effectiveness in the dry reforming of methane. The reactions were conducted at 700 °C in a tubular microreactor. The study compares the best-performing catalyst with a reference catalyst (5Ni/MgO) by conducting dry reforming of methane at different reaction temperatures. The catalysts are evaluated using surface area, porosity, X-ray diffraction, infrared spectroscopy, transmission electron microscope, thermogravimeter, and temperature-programmed techniques. The 5Ni/MgO + ZrO2 catalyst demonstrates inferior catalytic activity due to insufficient active sites. On the other hand, the 5Ni/MgO + TiO2 catalyst shows limited catalytic excellence due to excessive coke deposits, which are six times higher than other catalysts. The 5Ni/MgO and 5Ni/MgO + Al2O3 catalysts have the richest basic and acidic profiles, respectively. The 5Ni/MgO + Al2O3 catalyst is superior to other catalysts due to its stronger metal–support interaction on the expanded surface and the efficient diffusion of carbon on its less crystalline surface. At 700 °C, this catalyst achieves 73% CH4 conversion, and at 800 °C, it reaches 83% conversion. This study emphasizes the crucial role of the reaction temperature in reducing carbon deposition and enhancing the efficiency of the reforming process.
{"title":"Tailored Ni-MgO Catalysts: Unveiling Temperature-Driven Synergy in CH4-CO2 Reforming","authors":"Ahmad M. Alghamdi, A. Ibrahim, Fekri Abdulraqeb Ahmed Ali, Nouf A. Bamatraf, A. Fakeeha, Ahmed I. Osman, S. Alreshaidan, Farid Fadhillah, S. Al‐Zahrani, Ahmed S. Al-Fatesh","doi":"10.3390/catal14010033","DOIUrl":"https://doi.org/10.3390/catal14010033","url":null,"abstract":"This study examines nickel catalysts on two different supports—magnesium oxide (MgO) and modified MgO (with 10 wt.% MOx; M = Ti, Zr, Al)—for their effectiveness in the dry reforming of methane. The reactions were conducted at 700 °C in a tubular microreactor. The study compares the best-performing catalyst with a reference catalyst (5Ni/MgO) by conducting dry reforming of methane at different reaction temperatures. The catalysts are evaluated using surface area, porosity, X-ray diffraction, infrared spectroscopy, transmission electron microscope, thermogravimeter, and temperature-programmed techniques. The 5Ni/MgO + ZrO2 catalyst demonstrates inferior catalytic activity due to insufficient active sites. On the other hand, the 5Ni/MgO + TiO2 catalyst shows limited catalytic excellence due to excessive coke deposits, which are six times higher than other catalysts. The 5Ni/MgO and 5Ni/MgO + Al2O3 catalysts have the richest basic and acidic profiles, respectively. The 5Ni/MgO + Al2O3 catalyst is superior to other catalysts due to its stronger metal–support interaction on the expanded surface and the efficient diffusion of carbon on its less crystalline surface. At 700 °C, this catalyst achieves 73% CH4 conversion, and at 800 °C, it reaches 83% conversion. This study emphasizes the crucial role of the reaction temperature in reducing carbon deposition and enhancing the efficiency of the reforming process.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":" 24","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139138537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The preparation of high-value-added platform compounds from biomass materials provides an important method for solving fossil energy shortages. Known as the “sleeping giant”, 5-HMF is one of the most important biomass platform compounds with promising applications. At present, raw materials for the preparation of 5-HMF mainly comprise sugar compounds and non-food biomass. The current systems for preparing 5-HMF are disadvantaged by poor selectivity and a low conversion rate. This paper focuses on the catalytic mechanisms and catalytic systems for the synthesis of 5-HMF from different biomass feedstocks and reviews a series of existing techniques for the preparation of 5-HMF. Catalytic systems for the synthesis of 5-HMF from different feedstocks are also discussed in depth, providing theoretical support for its subsequent in-depth study. The development of efficient catalysts and catalytic systems for the conversion of polysaccharide raw materials into 5-HMF is anticipated.
{"title":"Catalytic Systems for 5-Hydroxymethylfurfural Preparation from Different Biomass Feedstocks: A Review","authors":"Jiao Tao, Yunchuan Pan, Haiyang Zhou, Yufei Tang, Guoquan Ren, Zhihao Yu, Jiaxuan Li, Rui Zhang, Xiaoyun Li, Yina Qiao, Xuebin Lu, Jian Xiong","doi":"10.3390/catal14010030","DOIUrl":"https://doi.org/10.3390/catal14010030","url":null,"abstract":"The preparation of high-value-added platform compounds from biomass materials provides an important method for solving fossil energy shortages. Known as the “sleeping giant”, 5-HMF is one of the most important biomass platform compounds with promising applications. At present, raw materials for the preparation of 5-HMF mainly comprise sugar compounds and non-food biomass. The current systems for preparing 5-HMF are disadvantaged by poor selectivity and a low conversion rate. This paper focuses on the catalytic mechanisms and catalytic systems for the synthesis of 5-HMF from different biomass feedstocks and reviews a series of existing techniques for the preparation of 5-HMF. Catalytic systems for the synthesis of 5-HMF from different feedstocks are also discussed in depth, providing theoretical support for its subsequent in-depth study. The development of efficient catalysts and catalytic systems for the conversion of polysaccharide raw materials into 5-HMF is anticipated.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":" 19","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139142989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We used ab initio molecular dynamics simulations to compare the activation of 2-propanol on the low index Co3O4 (111), (110) and (001) surfaces in dry conditions. The thermal and surface assisted decomposition of a film of 2-propanol to 2-propoxide on the B-termination of each surface was monitored and analyzed. The investigations suggest an activity order of Co3O4 (111) > (110) > (001). On all surfaces, the Co3+ serves as an adsorption sites. On the B-terminated (111) surface, full dissociation of all 2-propanol molecules at the interface is observed, accompanied by a Mars-van Krevelen-type mechanism upon pre-hydroxylation of the surface. The active regions show Co3+–O2-propoxide–Co2+ bridges where the coordinatively unsaturated Co2+ ions also participate in the adsorption and decomposition of 2-propanol. On the (110) surface, 2-propanol dissociation is driven by temperature, which activates the two-fold coordinatively unsaturated surface oxygens. The (001) surface on which almost no dissociation occurs is the least active. No formation of acetone is observed in the simulations conditions on all surfaces.
我们利用 ab initio 分子动力学模拟比较了在干燥条件下 2-丙醇在低指数 Co3O4 (111)、(110) 和 (001) 表面上的活化情况。对每种表面的 B 端上将 2-丙醇分解为 2-丙氧基的薄膜的热分解和表面辅助分解进行了监测和分析。研究表明，Co3O4 的活性顺序为 (111) > (110) > (001)。在所有表面上，Co3+ 都是吸附位点。在 B 端（111）表面，观察到所有 2-丙醇分子在界面上完全解离，并伴随着表面预羟基化后的 Mars-van Krevelen 型机制。活性区域显示出 Co3+-O2-propoxide-Co2+ 桥，其中配位不饱和的 Co2+ 离子也参与了 2-丙醇的吸附和分解。在（110）表面，2-丙醇的解离是由温度驱动的，温度激活了表面的两倍配位不饱和氧原子。几乎不发生解离的 (001) 表面活性最低。在所有表面的模拟条件下都没有观察到丙酮的形成。
{"title":"2-Propanol Activation on the Low Index Co3O4 Surfaces: A Comparative Study Using Molecular Dynamics Simulations","authors":"A. H. Omranpoor, S. Kenmoe","doi":"10.3390/catal14010025","DOIUrl":"https://doi.org/10.3390/catal14010025","url":null,"abstract":"We used ab initio molecular dynamics simulations to compare the activation of 2-propanol on the low index Co3O4 (111), (110) and (001) surfaces in dry conditions. The thermal and surface assisted decomposition of a film of 2-propanol to 2-propoxide on the B-termination of each surface was monitored and analyzed. The investigations suggest an activity order of Co3O4 (111) > (110) > (001). On all surfaces, the Co3+ serves as an adsorption sites. On the B-terminated (111) surface, full dissociation of all 2-propanol molecules at the interface is observed, accompanied by a Mars-van Krevelen-type mechanism upon pre-hydroxylation of the surface. The active regions show Co3+–O2-propoxide–Co2+ bridges where the coordinatively unsaturated Co2+ ions also participate in the adsorption and decomposition of 2-propanol. On the (110) surface, 2-propanol dissociation is driven by temperature, which activates the two-fold coordinatively unsaturated surface oxygens. The (001) surface on which almost no dissociation occurs is the least active. No formation of acetone is observed in the simulations conditions on all surfaces.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"244 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2023-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139152737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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