Single-atom catalysts(SACs)are considered as the most promising nonprecious metal alternatives for oxygen reduction reactions(ORR)in proton exchange membrane fuel cells because of their high atomic utilization and exc...Single-atom catalysts(SACs)are considered as the most promising nonprecious metal alternatives for oxygen reduction reactions(ORR)in proton exchange membrane fuel cells because of their high atomic utilization and excellent catalytic performance.However,the inadequate activity and long-term stability of SACs under operational conditions significantly hinder their practical application.Therefore,this paper focuses on understanding the micro-and electronic structures that synergistically enable the activity and stability of oxygen reduction.It provides a comprehensive summary of the effects for improving the ORR catalytic activity and stability of SACs from a multilevel,multi-angle perspective,including macroscale adjustments to the overall catalyst structure,nanoscale optimization of the catalyst microstructure,and atomic-scale regulation of the active sites.Additionally,it emphasizes the importance of advanced simulation,computational methods,and characterization techniques in understanding the catalytic and degradation mechanisms of SACs during the ORR process.This review aims to provide a theoretical foundation for the synergistic catalytic mechanisms and long-term stable operation of catalytic sites in complex heterogeneous environments,thereby advancing research on low-cost,high-efficiency,and highly stable single-atom catalysts.展开更多
In the traditional extractive distillation process,organic solvents are often used as entrainers.However,environmental influence and high energy-consumption are significant problems in industrial application.In this s...In the traditional extractive distillation process,organic solvents are often used as entrainers.However,environmental influence and high energy-consumption are significant problems in industrial application.In this study,a systematic screening strategy and innovative energy-saving design for ionic liquid-based extractive distillation process was proposed.The innovative energy-saving design focused on the binary minimum azeotrope mixtures isopropanol and water.Miscibility,environmental impact and physical properties(e.g.,melting point and viscosity)of 30 ionic liquids were investigated.1-Ethyl-3-methyl-imidazolium dicyanamide and 1-butyl-3-methyl-imidazolium dicyanamide were selected as candidate entrainers.Feasibility analysis of these two ionic liquids was further performed via residue curve maps,isovolatility line and temperature profiles.An innovative ionic liquid-based extractive distillation process combining distillation column and stripping column was designed and optimized with the objective function of minimizing the total annualized cost.The results demonstrate that the total annualized cost was reduced by 19.9%with 1-ethyl-3-methyl-imidazolium dicyanamide as the entrainer and by 24.3%with 1-butyl-3-methyl-imidazolium dicyanamide,compared with that of dimethyl sulfoxide.The method proposed in this study is conducive to the green and sustainable development of extractive distillation process.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22478423 and 22275026)the Natural Science Foundation for Distinguished Young Scholars of Chongqing,China(No.CSTB2023NSCQJQX0032)the key project of Chongqing Science and Technology Bureau(No.CSTB2022TIAD-KPX0041).
文摘Single-atom catalysts(SACs)are considered as the most promising nonprecious metal alternatives for oxygen reduction reactions(ORR)in proton exchange membrane fuel cells because of their high atomic utilization and excellent catalytic performance.However,the inadequate activity and long-term stability of SACs under operational conditions significantly hinder their practical application.Therefore,this paper focuses on understanding the micro-and electronic structures that synergistically enable the activity and stability of oxygen reduction.It provides a comprehensive summary of the effects for improving the ORR catalytic activity and stability of SACs from a multilevel,multi-angle perspective,including macroscale adjustments to the overall catalyst structure,nanoscale optimization of the catalyst microstructure,and atomic-scale regulation of the active sites.Additionally,it emphasizes the importance of advanced simulation,computational methods,and characterization techniques in understanding the catalytic and degradation mechanisms of SACs during the ORR process.This review aims to provide a theoretical foundation for the synergistic catalytic mechanisms and long-term stable operation of catalytic sites in complex heterogeneous environments,thereby advancing research on low-cost,high-efficiency,and highly stable single-atom catalysts.
基金supported by the National Natural Science Foundation of China(Grant No.21878028)the Chongqing Joint Chinese Medicine Scientific Research Project(Grant No.2020ZY023984)the Fundamental Research Funds for the Central Universities(Grant No.2022CDJXY-003).
文摘In the traditional extractive distillation process,organic solvents are often used as entrainers.However,environmental influence and high energy-consumption are significant problems in industrial application.In this study,a systematic screening strategy and innovative energy-saving design for ionic liquid-based extractive distillation process was proposed.The innovative energy-saving design focused on the binary minimum azeotrope mixtures isopropanol and water.Miscibility,environmental impact and physical properties(e.g.,melting point and viscosity)of 30 ionic liquids were investigated.1-Ethyl-3-methyl-imidazolium dicyanamide and 1-butyl-3-methyl-imidazolium dicyanamide were selected as candidate entrainers.Feasibility analysis of these two ionic liquids was further performed via residue curve maps,isovolatility line and temperature profiles.An innovative ionic liquid-based extractive distillation process combining distillation column and stripping column was designed and optimized with the objective function of minimizing the total annualized cost.The results demonstrate that the total annualized cost was reduced by 19.9%with 1-ethyl-3-methyl-imidazolium dicyanamide as the entrainer and by 24.3%with 1-butyl-3-methyl-imidazolium dicyanamide,compared with that of dimethyl sulfoxide.The method proposed in this study is conducive to the green and sustainable development of extractive distillation process.
