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.Herei...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 N2-bidentate(note that N2-bidentate site=N^N-bidentate site;N2¹dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N2-bidentate site,a Cu SAC with isolated undercoordinated Cu-N2 sites(Cu1.0/N2-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N2-GDY exhibits the highest Faradaic efficiency(FE)of 80.6%for CH4 in electrocatalytic reduction of CO_(2)at-0.96 V vs.RHE,and the partial current density of CH4 is 160 mA cm^(-2).The selectivity for CH4 is maintained above 70%when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N2-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-N2 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-N2 sites toward efficient electrocatalysis.展开更多
基于电子显微学的原子级三维重构技术对揭示材料的微观结构,加深材料结构和性能关系的理解具有极为重要的意义。原子级电子断层成像技术(atomic electron tomography,AET)作为当前最先进的三维重构技术之一,已先后成功表征了纳米颗粒中...基于电子显微学的原子级三维重构技术对揭示材料的微观结构,加深材料结构和性能关系的理解具有极为重要的意义。原子级电子断层成像技术(atomic electron tomography,AET)作为当前最先进的三维重构技术之一,已先后成功表征了纳米颗粒中原子位置、晶体缺陷、早期形核过程中原子的动态变化及非晶态固体的三维原子结构。本文综述了AET的流程及应用的突破,以期望读者了解AET的基本原理流程和应用,并探讨未来AET在解决物理、化学、材料科学等领域基础问题的前景与挑战。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 N2-bidentate(note that N2-bidentate site=N^N-bidentate site;N2¹dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N2-bidentate site,a Cu SAC with isolated undercoordinated Cu-N2 sites(Cu1.0/N2-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N2-GDY exhibits the highest Faradaic efficiency(FE)of 80.6%for CH4 in electrocatalytic reduction of CO_(2)at-0.96 V vs.RHE,and the partial current density of CH4 is 160 mA cm^(-2).The selectivity for CH4 is maintained above 70%when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N2-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-N2 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-N2 sites toward efficient electrocatalysis.
文摘基于电子显微学的原子级三维重构技术对揭示材料的微观结构,加深材料结构和性能关系的理解具有极为重要的意义。原子级电子断层成像技术(atomic electron tomography,AET)作为当前最先进的三维重构技术之一,已先后成功表征了纳米颗粒中原子位置、晶体缺陷、早期形核过程中原子的动态变化及非晶态固体的三维原子结构。本文综述了AET的流程及应用的突破,以期望读者了解AET的基本原理流程和应用,并探讨未来AET在解决物理、化学、材料科学等领域基础问题的前景与挑战。
