摘要
Utilizing electrocatalytic CO_(2)reduction(ECR)to decrease the carbon footprint has been regarded as a promising pathway.Herein,we report the synthesis of Ni nanoclusters(NCs)of below 2 nm highly dispersed on N-doped carbon using a Ni/Zn bimetallic metal-organic framework(MOF)precursor.The size and the content of the Ni catalyst can be effectively controlled by varying the Ni:Zn ratio in MOF precursors.The-NH2 group in MOF ligand critically influences the size of Ni catalyst,as well as the property of the carbon substrate.At the optimum ratio of 1:150,Ni NCs with an average size of 1.9 nm anchored on pyridinic N-rich carbon were obtained after MOF pyrolysis.The resultant catalyst exhibits a high Faradaic efficiency for CO(FECO,98.7%)and considerable partial current density for CO(JCO,−40.4 mA·cm^(−2))at−0.88 V versus reversible hydrogen electrode(RHE).Benefiting from the synergistic effect of small Ni clusters and their optimal interaction with the carbon support,the catalyst displays exceptional long-term stability.Density functional theory(DFT)calculations carried out for the three model structures confirm that Ni NCs anchored on N-doped carbon facilitate the easier formation of*COOH intermediate and faster electron transfer rate compared with the large-sized Ni particles represented by Ni(111)and the N-doped carbon without Ni.
基金
supported by Nanyang Technological University and the Singapore National Research Foundation(NRF)under its Campus for Research Excellence and Technological Enterprise(CREATE)program through the Cambridge Center for Advanced Research and Education in Singapore(CARES)Cambridge Center for Carbon Reduction in Chemical Technology(C4T)and through CARES and the Berkeley Educational Alliance for Research in Singapore(BEARS)eCO2P program.X.D.W.acknowledge the financial support from Natural Science Foundation of Jiangsu Province(No.BK20200711).
