Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Here...Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.展开更多
文摘Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.
