Pub Date : 2024-08-10DOI: 10.20517/microstructures.2024.26
Jessica Jein White, Ming Zhou, J. J. Hinsch, William W. Bennett, Yun Wang
The organochlorine contaminants in wastewater can be degraded by using sulfidated nanoscale zero-valent iron. However, the specific role of S dopants and the underlying degradation mechanism are largely unknown. In this study, we applied ab initio molecular dynamics and density functional theory to investigate the remediation mechanism of two chlorinated organic compounds, cis-dichloroethene and tetrachloroethene, focusing on the role of sulfur dopant coverage on the nZVI surface, represented by a stepped Fe(211) facet, and compare it to a flat (110) surface. Our results revealed that low S coverage facilitates the dissociation of the contaminants due to stronger interaction with the iron surface. Conversely, high S coverage initially hinders dissociation but promotes adsorption of the contaminants for later dissociation, suggesting a potential benefit for remediation. By comparing with the water molecule adsorption energies, we demonstrate that S doping enhances selectivity towards these contaminants only at high S coverage. Our theoretical findings, therefore, highlight the importance of optimizing S coverage for effective wastewater treatment using sulfidated nanoscale zero-valent iron.
废水中的有机氯污染物可通过使用硫化纳米级零价铁来降解。然而，S掺杂剂的具体作用和基本降解机制在很大程度上还不为人所知。在本研究中，我们应用 ab initio 分子动力学和密度泛函理论研究了两种氯化有机化合物（顺式二氯乙烷和四氯乙烯）的降解机制，重点研究了硫掺杂剂在 nZVI 表面（以阶梯状 Fe(211) 面为代表）上的作用，并将其与平面 (110) 表面进行了比较。我们的研究结果表明，由于与铁表面的相互作用较强，低硫覆盖率有利于污染物的解离。相反，高 S 覆盖率最初会阻碍污染物的解离，但会促进污染物的吸附，以便日后解离，这表明高 S 覆盖率对修复具有潜在的益处。通过与水分子吸附能的比较，我们证明只有在高 S 覆盖率的情况下，S 掺杂才能提高对这些污染物的选择性。因此，我们的理论发现强调了优化 S 覆盖率对于利用硫化纳米级零价铁有效处理废水的重要性。
{"title":"A theoretical investigation on sulfidated nanoscale zero valent iron for removal of cis-DCE and PCE","authors":"Jessica Jein White, Ming Zhou, J. J. Hinsch, William W. Bennett, Yun Wang","doi":"10.20517/microstructures.2024.26","DOIUrl":"https://doi.org/10.20517/microstructures.2024.26","url":null,"abstract":"The organochlorine contaminants in wastewater can be degraded by using sulfidated nanoscale zero-valent iron. However, the specific role of S dopants and the underlying degradation mechanism are largely unknown. In this study, we applied ab initio molecular dynamics and density functional theory to investigate the remediation mechanism of two chlorinated organic compounds, cis-dichloroethene and tetrachloroethene, focusing on the role of sulfur dopant coverage on the nZVI surface, represented by a stepped Fe(211) facet, and compare it to a flat (110) surface. Our results revealed that low S coverage facilitates the dissociation of the contaminants due to stronger interaction with the iron surface. Conversely, high S coverage initially hinders dissociation but promotes adsorption of the contaminants for later dissociation, suggesting a potential benefit for remediation. By comparing with the water molecule adsorption energies, we demonstrate that S doping enhances selectivity towards these contaminants only at high S coverage. Our theoretical findings, therefore, highlight the importance of optimizing S coverage for effective wastewater treatment using sulfidated nanoscale zero-valent iron.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"11 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921353","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}
Pub Date : 2024-08-09DOI: 10.20517/microstructures.2024.15
Ning Liu, Tengfei Hu, Zhengqian Fu, Jingxian Zhang, Y. Duan, Zhen Wang, Fangfang Xu, Shaoming Dong
Si3N4 ceramics, renowned for their superior mechanical properties, are widely regarded as the most promising materials for electronic device casing. This is particularly evident in the context of 5th generation mobile networks, where they outperform both glass and zirconia. However, achieving a synergetic balance between color and mechanical properties remains a significant challenge. In this study, we propose the use of phase separation in liquid phases, supported by a novel Eu2O3-YAG-MgO system, to engineer hollow structures. This approach aims to achieve high-toughness colored Si3N4 ceramics. The resulting hollow structure not only acts as a reinforcing phase in response to the stress field caused by lattice mismatch but also serves as one of the dominant chromophores. This is achieved through the 5d→4f transition of Eu2+ coupled with the 5D0→7FJ transition of Eu3+ under photon excitation. These findings offer new insights into the development of high-performance Si3N4 ceramics with well-controlled color.
{"title":"Synergistic regulation of color and mechanical properties of silicon nitride ceramics via engineering hollow structures of Eu-enriched secondary phases","authors":"Ning Liu, Tengfei Hu, Zhengqian Fu, Jingxian Zhang, Y. Duan, Zhen Wang, Fangfang Xu, Shaoming Dong","doi":"10.20517/microstructures.2024.15","DOIUrl":"https://doi.org/10.20517/microstructures.2024.15","url":null,"abstract":"Si3N4 ceramics, renowned for their superior mechanical properties, are widely regarded as the most promising materials for electronic device casing. This is particularly evident in the context of 5th generation mobile networks, where they outperform both glass and zirconia. However, achieving a synergetic balance between color and mechanical properties remains a significant challenge. In this study, we propose the use of phase separation in liquid phases, supported by a novel Eu2O3-YAG-MgO system, to engineer hollow structures. This approach aims to achieve high-toughness colored Si3N4 ceramics. The resulting hollow structure not only acts as a reinforcing phase in response to the stress field caused by lattice mismatch but also serves as one of the dominant chromophores. This is achieved through the 5d→4f transition of Eu2+ coupled with the 5D0→7FJ transition of Eu3+ under photon excitation. These findings offer new insights into the development of high-performance Si3N4 ceramics with well-controlled color.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"45 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923003","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}
Pub Date : 2024-08-09DOI: 10.20517/microstructures.2024.33
G. Schuck, D. Többens, Susan Schorr
Based on previously published research, the structural response of the tetragonal hybrid perovskite crystal structure of MAPbX3 [MA: [CH3NH3]+, methylammonium; X = I, Br] to thermal expansion is reviewed here. From an averaged crystal structure perspective, the tetragonal perovskite structure of MAPbI3 and MAPbBr3, based on diffraction data, shows apparent Pb-X bond length shortening and apparent shrinkage of the [PbX6] octahedra with increasing temperature. At the same time, these apparent observations, and hence the thermal expansion, are related to the progressive phase transformation towards the cubic structure, as the lattice parameters respond to a shear stress that couples to the order parameters, and this coupling is predicted by group theory and thus aims to explain precisely the apparent negative thermal expansion-like effects. A different picture emerges for the thermal expansion when considering the very localized structure, since neither a shortening of the Pb-X bond lengths nor a shrinking of the [PbX6] octahedra is observed with pair distribution function analysis, and the presence of orthorhombic short-range order in the tetragonal and cubic perovskite structures is assumed in published studies. The compared extended X-ray absorption fine structure studies, which also map the local structure and provide the “true” bond distance, show no lead-halide bond length shortening with temperature. The perpendicular mean square relative displacement has been determined. Therefore, a comparison of the tension and bond expansion effects in both perovskites can be made. In the orthorhombic phase of MAPbI3 and MAPbBr3, positive expansion and negative tension of the lead-halide bond are almost balanced. After transitioning to the tetragonal phase, the equilibrium shifts toward negative tension. This suggests that both hybrid perovskites have tighter lead-halide bonds and less rigid [PbX6] octahedra in the tetragonal phase than in the low temperature perovskite crystal structure.
{"title":"On the thermal expansion of the tetragonal phase of MAPbI3 and MAPbBr3","authors":"G. Schuck, D. Többens, Susan Schorr","doi":"10.20517/microstructures.2024.33","DOIUrl":"https://doi.org/10.20517/microstructures.2024.33","url":null,"abstract":"Based on previously published research, the structural response of the tetragonal hybrid perovskite crystal structure of MAPbX3 [MA: [CH3NH3]+, methylammonium; X = I, Br] to thermal expansion is reviewed here. From an averaged crystal structure perspective, the tetragonal perovskite structure of MAPbI3 and MAPbBr3, based on diffraction data, shows apparent Pb-X bond length shortening and apparent shrinkage of the [PbX6] octahedra with increasing temperature. At the same time, these apparent observations, and hence the thermal expansion, are related to the progressive phase transformation towards the cubic structure, as the lattice parameters respond to a shear stress that couples to the order parameters, and this coupling is predicted by group theory and thus aims to explain precisely the apparent negative thermal expansion-like effects. A different picture emerges for the thermal expansion when considering the very localized structure, since neither a shortening of the Pb-X bond lengths nor a shrinking of the [PbX6] octahedra is observed with pair distribution function analysis, and the presence of orthorhombic short-range order in the tetragonal and cubic perovskite structures is assumed in published studies. The compared extended X-ray absorption fine structure studies, which also map the local structure and provide the “true” bond distance, show no lead-halide bond length shortening with temperature. The perpendicular mean square relative displacement has been determined. Therefore, a comparison of the tension and bond expansion effects in both perovskites can be made. In the orthorhombic phase of MAPbI3 and MAPbBr3, positive expansion and negative tension of the lead-halide bond are almost balanced. After transitioning to the tetragonal phase, the equilibrium shifts toward negative tension. This suggests that both hybrid perovskites have tighter lead-halide bonds and less rigid [PbX6] octahedra in the tetragonal phase than in the low temperature perovskite crystal structure.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"49 34","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923938","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}
To address energy shortages and environmental issues, prioritizing renewable energy development and usage is crucial. Employing renewable sources for water electrolysis offers a sustainable method for hydrogen generation. Reducing the water electrolysis potential is vital for efficient clean energy conversion and storage. Substituting the anodic oxygen evolution reaction in conventional hydrogen production from water electrolysis with the more thermodynamically favorable 5-hydroxymethylfurfural (HMF) oxidation reaction can greatly decrease overpotential and yield the valuable product 2,5-furan dicarboxylic acid. The key to this process is developing effective electrocatalysts to minimize the potential of the HMF electrooxidation-hydrogen production system. Therefore, this review provides a comprehensive introduction to the modulation strategies that affect the electronic and geometric structure of electrocatalysts for HMF oxidation-assisted water splitting. The strategies encompass heteroatom doping, defect projection, interface engineering, structural design, and multi-metal synergies. The catalysts are assessed from various angles, encompassing structural characterization, reaction mechanisms, and electrochemical performance. Finally, current challenges in the catalyst design and potential development of this promising field are proposed.
{"title":"Modulation strategies of electrocatalysts for 5-hydroxymethylfurfural oxidation-assisted water splitting","authors":"Tongxue Zhang, Shuai Liu, Fumin Wang, Wenxian Liu, Xinyuan He, Qian Liu, Xubin Zhang, Xijun Liu","doi":"10.20517/microstructures.2023.93","DOIUrl":"https://doi.org/10.20517/microstructures.2023.93","url":null,"abstract":"To address energy shortages and environmental issues, prioritizing renewable energy development and usage is crucial. Employing renewable sources for water electrolysis offers a sustainable method for hydrogen generation. Reducing the water electrolysis potential is vital for efficient clean energy conversion and storage. Substituting the anodic oxygen evolution reaction in conventional hydrogen production from water electrolysis with the more thermodynamically favorable 5-hydroxymethylfurfural (HMF) oxidation reaction can greatly decrease overpotential and yield the valuable product 2,5-furan dicarboxylic acid. The key to this process is developing effective electrocatalysts to minimize the potential of the HMF electrooxidation-hydrogen production system. Therefore, this review provides a comprehensive introduction to the modulation strategies that affect the electronic and geometric structure of electrocatalysts for HMF oxidation-assisted water splitting. The strategies encompass heteroatom doping, defect projection, interface engineering, structural design, and multi-metal synergies. The catalysts are assessed from various angles, encompassing structural characterization, reaction mechanisms, and electrochemical performance. Finally, current challenges in the catalyst design and potential development of this promising field are proposed.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"30 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141810206","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}
Pub Date : 2024-07-24DOI: 10.20517/microstructures.2024.19
Mattia Colalongo, Nikita Vostrov, Isaac Martens, E. Zatterin, Marie-Ingrid Richard, Francois Cadiou, Quentin Jacquet, J. Drnec, Steven J. Leake, Tanja Kallio, Xiaobo Zhu, S. Lyonnard, T. Schulli
The necessity of mapping crystal defects in battery materials after synthesis is crucial in understanding heterogeneity within a single crystal domain and among particles to develop superior crystal quality materials. Numerous imaging techniques have been developed over the past years to study these materials at the nanoscale. However, most of them use electron beams which demand many hours of sample preparation, and they are incompatible with the investigation of batteries under realistic working conditions. Techniques such as Scanning X-ray Diffraction Imaging (Scanning X-ray Diffraction Microscopy) or Bragg Coherent Diffraction Imaging are increasingly available on the latest generation synchrotron sources. Their progressive deployment will allow for a standardized method for imaging crystal lattice imperfections such as lattice tilt and strain in individual particles without any prior sample preparation. In this paper, we exploited Scanning X-ray Diffraction Microscopy to probe the strain variation in single crystals and polycrystalline particles and Bragg Coherent Diffraction Imaging to reconstruct the volume of a single crystal particle. Presented case studies were performed on particles of different active cathode materials ($$ rm{LiNi_{0.6}Mn_{0.2}Co_{0.2}O_{2}} $$ , $$ rm{LiNiO_{2}} $$ and $$ rm{LiMn_{1.5}Ni_{0.5}O_{4}} $$ ); however, these techniques can also be employed on other battery components for a more holistic structural understanding of used materials and (de)lithiation dynamics on the microscale.
电池材料在合成后必须绘制晶体缺陷图，这对于了解单晶域内和颗粒间的异质性以开发优质晶体材料至关重要。在过去的几年里，已经开发出许多成像技术，用于在纳米尺度上研究这些材料。然而，这些技术大多使用电子束，需要耗费大量时间制备样品，而且不适合在实际工作条件下研究电池。扫描 X 射线衍射成像（扫描 X 射线衍射显微镜）或布拉格相干衍射成像等技术越来越多地应用于最新一代同步辐射源。它们的逐步应用将为晶格缺陷成像（如单个颗粒中的晶格倾斜和应变）提供标准化方法，而无需事先制备样品。在本文中，我们利用扫描 X 射线衍射显微镜探测单晶和多晶颗粒的应变变化，并利用布拉格相干衍射成像重建单晶颗粒的体积。所介绍的案例研究是针对不同活性阴极材料（$$ rm{LiNi_{0.6}Mn_{0.2}Co_{0.2}O_{2}} 、$$ rm{LiNi_{0.6}Mn_{0.2}Co_{0.2}O_{2}} ）的颗粒进行的。$$ ， $$ rm{LiNiO_{2}}$$ 和 $$ rm{LiMn_{1.5}Ni_{0.5}O_{4}}} ）。然而，这些技术也可用于其他电池组件，以便更全面地了解所用材料的结构和微尺度上的（脱）锂化动力学。
{"title":"Imaging inter - and intra-particle features in crystalline cathode materials for Li-ion batteries using nano-focused beam techniques at 4th generation synchrotron sources","authors":"Mattia Colalongo, Nikita Vostrov, Isaac Martens, E. Zatterin, Marie-Ingrid Richard, Francois Cadiou, Quentin Jacquet, J. Drnec, Steven J. Leake, Tanja Kallio, Xiaobo Zhu, S. Lyonnard, T. Schulli","doi":"10.20517/microstructures.2024.19","DOIUrl":"https://doi.org/10.20517/microstructures.2024.19","url":null,"abstract":"The necessity of mapping crystal defects in battery materials after synthesis is crucial in understanding heterogeneity within a single crystal domain and among particles to develop superior crystal quality materials. Numerous imaging techniques have been developed over the past years to study these materials at the nanoscale. However, most of them use electron beams which demand many hours of sample preparation, and they are incompatible with the investigation of batteries under realistic working conditions. Techniques such as Scanning X-ray Diffraction Imaging (Scanning X-ray Diffraction Microscopy) or Bragg Coherent Diffraction Imaging are increasingly available on the latest generation synchrotron sources. Their progressive deployment will allow for a standardized method for imaging crystal lattice imperfections such as lattice tilt and strain in individual particles without any prior sample preparation. In this paper, we exploited Scanning X-ray Diffraction Microscopy to probe the strain variation in single crystals and polycrystalline particles and Bragg Coherent Diffraction Imaging to reconstruct the volume of a single crystal particle. Presented case studies were performed on particles of different active cathode materials ($$ rm{LiNi_{0.6}Mn_{0.2}Co_{0.2}O_{2}} $$ , $$ rm{LiNiO_{2}} $$ and $$ rm{LiMn_{1.5}Ni_{0.5}O_{4}} $$ ); however, these techniques can also be employed on other battery components for a more holistic structural understanding of used materials and (de)lithiation dynamics on the microscale.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"63 19","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809341","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}
Pub Date : 2024-07-17DOI: 10.20517/microstructures.2024.06
Nan Yang, Tianwei He, Xinqi Chen, Yijun He, Tong Zhou, G. Zhang, Qingju Liu
Solar-driven photocatalysis hydrogen evolution is a promising method to generate hydrogen from water, a green and clean energy source, using solar and semiconductors. Up to now, TiO2 still represents the most inexpensive and widely studied metal oxide semiconductors for photocatalysis. TiO2 coupling with other semiconductors to form heterojunctions is considered an efficient way to improve photocatalytic performances. In this review, TiO2-based heterojunctions are classified into conventional, p-n type, Z-scheme, S-scheme, and other heterojunctions based on their band structures. The photocatalytic mechanisms of various types of heterojunctions are described in detail. In order to rationally design and better synthesize heterojunctions with excellent performance, the contribution of theoretical calculations to the field of TiO2-based heterojunction photocatalysts and the key role of theoretical prediction are also discussed. Finally, the opportunities and current challenges to promote photocatalytic performance are provided to assist the design of TiO2-based heterojunction photocatalysts with superior performance.
{"title":"TiO2-based heterojunctions for photocatalytic hydrogen evolution reaction","authors":"Nan Yang, Tianwei He, Xinqi Chen, Yijun He, Tong Zhou, G. Zhang, Qingju Liu","doi":"10.20517/microstructures.2024.06","DOIUrl":"https://doi.org/10.20517/microstructures.2024.06","url":null,"abstract":"Solar-driven photocatalysis hydrogen evolution is a promising method to generate hydrogen from water, a green and clean energy source, using solar and semiconductors. Up to now, TiO2 still represents the most inexpensive and widely studied metal oxide semiconductors for photocatalysis. TiO2 coupling with other semiconductors to form heterojunctions is considered an efficient way to improve photocatalytic performances. In this review, TiO2-based heterojunctions are classified into conventional, p-n type, Z-scheme, S-scheme, and other heterojunctions based on their band structures. The photocatalytic mechanisms of various types of heterojunctions are described in detail. In order to rationally design and better synthesize heterojunctions with excellent performance, the contribution of theoretical calculations to the field of TiO2-based heterojunction photocatalysts and the key role of theoretical prediction are also discussed. Finally, the opportunities and current challenges to promote photocatalytic performance are provided to assist the design of TiO2-based heterojunction photocatalysts with superior performance.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":" 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141831509","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}
Pub Date : 2024-07-09DOI: 10.20517/microstructures.2024.03
Fan Zhang, Wei Liu
As a highly intricate process encompassing multiple length scales, catalysis research evolves into a comprehensive understanding of reaction kinetics across microscopic to atomic dimensions when electron microscopy, particularly the in situ transmission electron microscopy (TEM), emerges to be increasingly relevant. Meanwhile, the absence of effective methodologies for measuring reaction products during catalysis complicates efforts to elucidate the operational state and catalytic activity of the catalyst. With ongoing advancements of refined gas-cell design within TEM and other in situ accessories, diverse methodologies have emerged to ascertain the occurrence of chemical reactions. In this review, we summarized the recent progress of operando TEM while further extending its conceptual boundaries by including newly emerged reaction-detecting approaches capable of bridging microstructure to the reaction process. These methods involve not only traditional ones of product detection, e.g., in situ mass spectrometry and electron energy loss spectroscopy, but also other reaction-correlative characterizations, such as directly imaging reactant molecule, modified in situ reactor for thermogravimetry and temperature-programmed reaction, and TEM image-based microstructure quantification and activity correlation. Applications, inherent challenges, and our perspectives within these operando TEM techniques are deliberated.
催化反应是一个包含多种长度尺度的高度复杂的过程，当电子显微镜，尤其是原位透射电子显微镜（TEM）变得越来越重要时，催化研究就发展成为对从微观到原子层面的反应动力学的全面了解。同时，由于缺乏有效的方法来测量催化反应过程中的反应产物，使得阐明催化剂运行状态和催化活性的工作变得更加复杂。随着 TEM 和其他原位配件中精细气室设计的不断进步，出现了多种方法来确定化学反应的发生。在本综述中，我们总结了操作式 TEM 的最新进展，同时进一步扩展了其概念边界，纳入了新出现的反应检测方法，这些方法能够将微观结构与反应过程联系起来。这些方法不仅包括传统的产物检测方法，如原位质谱法和电子能量损失光谱法，还包括其他反应相关表征方法，如直接成像反应物分子、用于热重分析和温度编程反应的改良原位反应器，以及基于 TEM 图像的微观结构量化和活性相关性。本文讨论了这些操作型 TEM 技术的应用、固有挑战和我们的观点。
{"title":"Recent progress of operando transmission electron microscopy in heterogeneous catalysis","authors":"Fan Zhang, Wei Liu","doi":"10.20517/microstructures.2024.03","DOIUrl":"https://doi.org/10.20517/microstructures.2024.03","url":null,"abstract":"As a highly intricate process encompassing multiple length scales, catalysis research evolves into a comprehensive understanding of reaction kinetics across microscopic to atomic dimensions when electron microscopy, particularly the in situ transmission electron microscopy (TEM), emerges to be increasingly relevant. Meanwhile, the absence of effective methodologies for measuring reaction products during catalysis complicates efforts to elucidate the operational state and catalytic activity of the catalyst. With ongoing advancements of refined gas-cell design within TEM and other in situ accessories, diverse methodologies have emerged to ascertain the occurrence of chemical reactions. In this review, we summarized the recent progress of operando TEM while further extending its conceptual boundaries by including newly emerged reaction-detecting approaches capable of bridging microstructure to the reaction process. These methods involve not only traditional ones of product detection, e.g., in situ mass spectrometry and electron energy loss spectroscopy, but also other reaction-correlative characterizations, such as directly imaging reactant molecule, modified in situ reactor for thermogravimetry and temperature-programmed reaction, and TEM image-based microstructure quantification and activity correlation. Applications, inherent challenges, and our perspectives within these operando TEM techniques are deliberated.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"65 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141664894","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}
Pub Date : 2024-07-04DOI: 10.20517/microstructures.2023.98
Fei Wang, Dan Li, Jian Mao
Cerium dioxide (CeO2) has emerged as a promising electrocatalyst for electrocatalytic nitrate reduction to produce ammonia (NRA). However, the NRA performance of CeO2 still needs to be improved and the interface-related NRA electrocatalytic activity of CeO2 is unclear. Herein, CeO2 with exposed (111) or (200)/(220) planes is prepared by adjusting the amount of added surfactant simply. The CeO2 with exposed (220)/(200) planes presents higher NRA performance than that of CeO2 with the exposed (111) plane. Based on density functional theory, the enhanced mechanism is revealed. The exposed (111) plane of CeO2 repels $$mathrm{NO}_{3}^{-}$$ , interrupting the following NRA processes. For exposed (200)/(220) planes of CeO2, they show high affinity for $$mathrm{NO}_{3}^{-}$$ and relatively low energy barriers for NRA reactions, bringing about enhanced NRA performance. This work shows a crystal-plane-dependent strategy for enhancing the catalytic performance of electrocatalysts.
{"title":"Control of exposed crystal planes of CeO2 enhances electrocatalytic nitrate reduction","authors":"Fei Wang, Dan Li, Jian Mao","doi":"10.20517/microstructures.2023.98","DOIUrl":"https://doi.org/10.20517/microstructures.2023.98","url":null,"abstract":"Cerium dioxide (CeO2) has emerged as a promising electrocatalyst for electrocatalytic nitrate reduction to produce ammonia (NRA). However, the NRA performance of CeO2 still needs to be improved and the interface-related NRA electrocatalytic activity of CeO2 is unclear. Herein, CeO2 with exposed (111) or (200)/(220) planes is prepared by adjusting the amount of added surfactant simply. The CeO2 with exposed (220)/(200) planes presents higher NRA performance than that of CeO2 with the exposed (111) plane. Based on density functional theory, the enhanced mechanism is revealed. The exposed (111) plane of CeO2 repels $$mathrm{NO}_{3}^{-}$$ , interrupting the following NRA processes. For exposed (200)/(220) planes of CeO2, they show high affinity for $$mathrm{NO}_{3}^{-}$$ and relatively low energy barriers for NRA reactions, bringing about enhanced NRA performance. This work shows a crystal-plane-dependent strategy for enhancing the catalytic performance of electrocatalysts.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":" 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141677521","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}
Pub Date : 2024-06-12DOI: 10.20517/microstructures.2023.106
Jianfang Ren, Zhao Wang, Nixon Du, Wenlong Cheng, L. Ju
Cardiovascular diseases, primarily driven by thrombosis, remain the leading cause of global mortality. Although traditional cell culture and animal models have provided foundational insights, they often fail to capture the complex pathophysiology of thrombosis, which hinders the development of targeted therapies for cardiovascular diseases. The advent of microfluidics and vascular tissue engineering has propelled the advancement of vessel-on-a-chip technologies, which enable the simulation of the key aspects of Virchow’s Triad: hypercoagulability, alteration in blood flow, and endothelial wall injury. With the ability to replicate patient-specific vascular architectures and hemodynamic conditions, vessel-on-a-chip models offer unprecedented insights into the mechanisms underlying thrombosis formation and progression. This review explores the evolution of microfluidic technologies in thrombosis research, highlighting breakthroughs in endothelialized devices and their roles in emulating conditions such as vessel stenosis, flow reversal, and endothelial damage. The limitations and challenges of the current vessel-on-a-chip systems are addressed, and future perspectives on the potential for personalized medicine and targeted therapies are presented. Vessel-on-a-chip technology holds immense potential for revolutionizing thrombosis research, enabling the development of targeted, patient-specific diagnostic tools and therapeutic strategies. Realizing this potential will require interdisciplinary collaboration and continued innovation in the fields of microfluidics and vascular tissue engineering.
{"title":"Charting the course of blood flow: vessel-on-a-chip technologies in thrombosis studies","authors":"Jianfang Ren, Zhao Wang, Nixon Du, Wenlong Cheng, L. Ju","doi":"10.20517/microstructures.2023.106","DOIUrl":"https://doi.org/10.20517/microstructures.2023.106","url":null,"abstract":"Cardiovascular diseases, primarily driven by thrombosis, remain the leading cause of global mortality. Although traditional cell culture and animal models have provided foundational insights, they often fail to capture the complex pathophysiology of thrombosis, which hinders the development of targeted therapies for cardiovascular diseases. The advent of microfluidics and vascular tissue engineering has propelled the advancement of vessel-on-a-chip technologies, which enable the simulation of the key aspects of Virchow’s Triad: hypercoagulability, alteration in blood flow, and endothelial wall injury. With the ability to replicate patient-specific vascular architectures and hemodynamic conditions, vessel-on-a-chip models offer unprecedented insights into the mechanisms underlying thrombosis formation and progression. This review explores the evolution of microfluidic technologies in thrombosis research, highlighting breakthroughs in endothelialized devices and their roles in emulating conditions such as vessel stenosis, flow reversal, and endothelial damage. The limitations and challenges of the current vessel-on-a-chip systems are addressed, and future perspectives on the potential for personalized medicine and targeted therapies are presented. Vessel-on-a-chip technology holds immense potential for revolutionizing thrombosis research, enabling the development of targeted, patient-specific diagnostic tools and therapeutic strategies. Realizing this potential will require interdisciplinary collaboration and continued innovation in the fields of microfluidics and vascular tissue engineering.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"135 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141351417","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}
Pub Date : 2024-06-11DOI: 10.20517/microstructures.2024.01
Zhaomeng Liu, Yingying Song, Shizheng Fu, Pengyan An, Mohan Dong, Shuran Wang, Qingsong Lai, Xuan‐Wen Gao, Wen-Bin Luo
Sodium-ion batteries (SIBs) are recognized as a leading option for energy storage systems, attributed to their environmental friendliness, natural abundance of sodium, and uncomplicated design. Cathode materials are crucial in defining the structural integrity and functional efficacy of SIBs. Recent studies have extensively focused on manganese (Mn)-based layered oxides, primarily due to their substantial specific capacity, cost-effectiveness, non-toxic nature, and ecological compatibility. Additionally, these materials offer a versatile voltage range and diverse configurational possibilities. However, the complex phase transition during a circular process affects its electrochemical performance. Herein, we set the multiphase Mn-based layered oxides as the research target and take the relationship between the structure and phase transition of these materials as the starting point, aiming to clarify the mechanism between the microstructure and phase transition of multiphase layered oxides. Meanwhile, the structure-activity relationship between structural changes and electrochemical performance of Mn-based layered oxides is revealed. Various modification methods for multiphase Mn-based layered oxides are summarized. As a result, a reasonable structural design is proposed for producing high-performance SIBs based on these oxides.
{"title":"Multiphase manganese-based layered oxide for sodium-ion batteries: structural change and phase transition","authors":"Zhaomeng Liu, Yingying Song, Shizheng Fu, Pengyan An, Mohan Dong, Shuran Wang, Qingsong Lai, Xuan‐Wen Gao, Wen-Bin Luo","doi":"10.20517/microstructures.2024.01","DOIUrl":"https://doi.org/10.20517/microstructures.2024.01","url":null,"abstract":"Sodium-ion batteries (SIBs) are recognized as a leading option for energy storage systems, attributed to their environmental friendliness, natural abundance of sodium, and uncomplicated design. Cathode materials are crucial in defining the structural integrity and functional efficacy of SIBs. Recent studies have extensively focused on manganese (Mn)-based layered oxides, primarily due to their substantial specific capacity, cost-effectiveness, non-toxic nature, and ecological compatibility. Additionally, these materials offer a versatile voltage range and diverse configurational possibilities. However, the complex phase transition during a circular process affects its electrochemical performance. Herein, we set the multiphase Mn-based layered oxides as the research target and take the relationship between the structure and phase transition of these materials as the starting point, aiming to clarify the mechanism between the microstructure and phase transition of multiphase layered oxides. Meanwhile, the structure-activity relationship between structural changes and electrochemical performance of Mn-based layered oxides is revealed. Various modification methods for multiphase Mn-based layered oxides are summarized. As a result, a reasonable structural design is proposed for producing high-performance SIBs based on these oxides.","PeriodicalId":515723,"journal":{"name":"Microstructures","volume":"16 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141355859","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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