Heteroatom-doped carbon-based transition-metal single-atom catalysts(SACs) are promising electrocatalysts for oxygen reduction reaction(ORR). Herein, with the aid of hierarchically porous silica as hard template, a fa...Heteroatom-doped carbon-based transition-metal single-atom catalysts(SACs) are promising electrocatalysts for oxygen reduction reaction(ORR). Herein, with the aid of hierarchically porous silica as hard template, a facile and general melting perfusion and mesopore-confined pyrolysis method was reported to prepare single-atomic Fe/N–S-doped carbon catalyst(FeNx/NC-S) with hierarchically porous structure and well-defined morphology. The FeNx/NC-S exhibited excellent ORR activity with a half-wave potential(E_(1/2)) of 0.92 V, and a lower overpotential of 320 mV at a current density of 10 mA cm^(-2)for OER under alkaline condition. The remarkable electrocatalysis performance can be attributed to the hierarchically porous carbon nanospheres with S doping and high content of Fe-Nx sites(up to 3.7 wt% of Fe), resulting from the nano-confinement effect of the hierarchically porous silica spheres(NKM-5) during the pyrolysis process. The rechargeable Zn-air battery with FeNx/NC-S as a cathode catalyst demonstrated a superior power density of 194.5 mW cm-2charge–discharge stability. This work highlights a new avenue to design advanced SACs for efficient sustainable energy storage and conversion.展开更多
Hierarchically porous zeolites are promising candidates in catalytic conversion of relatively bulky molecules,and their syntheses have attracted significant attention.From both industrial and scientific perspectives,d...Hierarchically porous zeolites are promising candidates in catalytic conversion of relatively bulky molecules,and their syntheses have attracted significant attention.From both industrial and scientific perspectives,different carbon materials have been widely employed as hard templates for the preparation of hierarchically porous zeolites during the past two decades.In this review,the progress in synthetic strategies using carbon materials as templates is comprehensively summarized.Depending on the affinity between the carbon templates and zeolite precursors,the substantial strategies for synthesizing hierarchical zeolites are introduced in direct templates and indirect templates.Direct templates methods,by which the carbon materials are directly mixed with precursors gel as hard templates,are first reviewed.Then,we discuss the indirect templates method(crystallization of carbon-silica composites),by which the carbon is produced by in situ pyrolysis of organic-inorganic precursors.In addition,the technique of encapsulating metal species into zeolites crystals with the assistance of carbon templates is also discussed.In the conclusion part,the factors affecting the synthesis of carbon-templated hierarchically porous zeolites are remarked.This review is expected to attract interest in the synthesis strategies of hierarchically porous zeolites,especially cost-effective and large-scale production methodologies,which are essential to the industrial application of hierarchical zeolites.展开更多
基金supported by National Natural Science Foundation of China (21773128)。
文摘Heteroatom-doped carbon-based transition-metal single-atom catalysts(SACs) are promising electrocatalysts for oxygen reduction reaction(ORR). Herein, with the aid of hierarchically porous silica as hard template, a facile and general melting perfusion and mesopore-confined pyrolysis method was reported to prepare single-atomic Fe/N–S-doped carbon catalyst(FeNx/NC-S) with hierarchically porous structure and well-defined morphology. The FeNx/NC-S exhibited excellent ORR activity with a half-wave potential(E_(1/2)) of 0.92 V, and a lower overpotential of 320 mV at a current density of 10 mA cm^(-2)for OER under alkaline condition. The remarkable electrocatalysis performance can be attributed to the hierarchically porous carbon nanospheres with S doping and high content of Fe-Nx sites(up to 3.7 wt% of Fe), resulting from the nano-confinement effect of the hierarchically porous silica spheres(NKM-5) during the pyrolysis process. The rechargeable Zn-air battery with FeNx/NC-S as a cathode catalyst demonstrated a superior power density of 194.5 mW cm-2charge–discharge stability. This work highlights a new avenue to design advanced SACs for efficient sustainable energy storage and conversion.
基金supported by the National Natural Science Foundation of China(Grant No.21773128).
文摘Hierarchically porous zeolites are promising candidates in catalytic conversion of relatively bulky molecules,and their syntheses have attracted significant attention.From both industrial and scientific perspectives,different carbon materials have been widely employed as hard templates for the preparation of hierarchically porous zeolites during the past two decades.In this review,the progress in synthetic strategies using carbon materials as templates is comprehensively summarized.Depending on the affinity between the carbon templates and zeolite precursors,the substantial strategies for synthesizing hierarchical zeolites are introduced in direct templates and indirect templates.Direct templates methods,by which the carbon materials are directly mixed with precursors gel as hard templates,are first reviewed.Then,we discuss the indirect templates method(crystallization of carbon-silica composites),by which the carbon is produced by in situ pyrolysis of organic-inorganic precursors.In addition,the technique of encapsulating metal species into zeolites crystals with the assistance of carbon templates is also discussed.In the conclusion part,the factors affecting the synthesis of carbon-templated hierarchically porous zeolites are remarked.This review is expected to attract interest in the synthesis strategies of hierarchically porous zeolites,especially cost-effective and large-scale production methodologies,which are essential to the industrial application of hierarchical zeolites.
