The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activit...The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low price.However,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic performance.In the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)hydrogenation.An anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active species.While interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over time.Finally,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration increased.This finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.展开更多
基金supported by the Shanghai Post-Doctoral Excellence Program(No.2021232)Y.He thanks the National Natural Science Foundation of China(No.22202131)+3 种基金the Shanghai Science and Technology Development Funds of“Rising Star”Sailing Program(No.22YF1419400)for the financial supportM.Zhu thanks the research funding sponsored by the National Natural Science Foundation of China(No.22078089)the Shanghai Special Program for Fundamental Research(No.22TQ1400100-7)the Basic Research Program of Science and Technology Commission of Shanghai Municipality(No.22JC1400600)。
文摘The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct manner.Due to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low price.However,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic performance.In the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)hydrogenation.An anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active species.While interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over time.Finally,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration increased.This finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.
