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将二氧化碳转化为高附加值的燃料和化学品是缓解当前能源和环境危机的有效策略之一.众所周知,铜基纳米材料是电还原二氧化碳的良好催化剂,但仍存在选择性低和耐久性差等缺点.本文中,我们以Cu-NBDC MOF为前驱体,通过退火得到了一种锚定在氮掺杂多孔碳上的Cu2O/Cu催化剂(Cu2O/Cu@NC).XPS结果显示,Cu2O/Cu@NC中的Cu-N含量随着退火温度升高而降低.通过电还原二氧化碳测试结果分析,我们发现与不含氮的Cu2O/Cu@C相比,Cu2O/Cu@NC有效抑制了副反应HER,提高了电还原二氧化碳反应的整体催化活性,而且随着Cu-N含量的增加,Cu2O/Cu@NC对乙烯和甲烷的选择性得到显著提高.在400℃退火处理下,Cu2O/Cu@NC的CO2催化效率高于86％(-1.4--1.6Vvs.RHE),其中包括20.4％的C2H4(-1.4 V vs.RHE)和23.9％的CH4(-1.6 V vs.RHE).相比之下,Cu2O/Cu@C的二氧化碳还原效率最高不足50％,且无明显乙烯和甲烷生成.我们认为这些显著的催化性能差异主要归因于Cu-N有利于稳定二氧化碳还原反应中*CH2中间体的吸附,抑制*H生成氢气.这些结果表明,通过调控氮的掺杂可以有效改变铜基MOF衍生的催化剂的二氧化碳还原路径并提高其催化性能.“,”With the development of human society and economy,the demand for energy resources has also increased rapidly.However,the use of traditional fossil energy leads to high amounts of carbon dioxide emissions,causing severe greenhouse effects.This,in turn,triggers a series of environmental problems.Harnessing renewable energy such as solar energy,wind energy,and hydropower to replace the traditional energy sources is very urgent.Conversion CO2 into value-added fuels and chemicals could be a useful strategy to mitigate the current energy and environmental crisis.It is well known that Cu-based materials are good electrocatalysts for the electrochemical reduction of CO2(ECR-CO2).However,they suffer from some disadvantages such as high overpotential and poor selectivity and durability.Therefore,the development of copper based electrocatalysts with high activity and selectivity is essential.Metal-organic frameworks(MOFs)materials that have the advantages of large specific surface area,tunable pore size and porosity,and highly dispersed unsaturated metal centers can be used as electrocatalysts for CO2 reduction or as precursors for further preparation of catalysts with excellent performance.Through thermal decomposition in an inert atmosphere,metal ions in MOF can be transformed into metal clusters,metal oxides,or even metal mono-atoms.Meanwhile,organic ligands are carbonized into porous carbon materials.The addition of some heteroatoms such as B,N,P,and S to carbon materials has also been shown to be effective in changing the electron state and coordination structure of the catalysts.These heteroatoms combine with carbon atoms to form a new active site,denoted as M-X-C(M is the central metal ion and X is the mixed heteroatom)to enhance the catalytic activity of the ECR-CO2.Herein,pre-synthesized Cu-NBDC MOF(a Cu-based MOF synthesized by using 2-aminoterephthalic acid(NBDC)as ligand)is used as a precursor to anchor Cu2O/Cu on nitrogen doped porous carbon(Cu2O/Cu@NC)by annealing at different temperatures.XPS analysis shows that the Cu-N content in Cu2O/Cu@NC decreases with increasing annealing temperature.Investigation of the ECR-CO2 reveals that Cu2O/Cu@NC can inhibit the HER more effectively compared to Cu2O/Cu@C,thereby improving the overall catalytic activity and multi-electron product selectivity of the ECR-CO2.While the Faradic efficiency of formate(FEformate)increases with increasing temperature,those of ethylene and methane(FEC2H4 and FECH4,respectively)decreases with increasing temperature.Specifically,upon annealing at 400℃,the CO2 Faradic efficiency of Cu2O/Cu@NC-400 is higher than 86％(-1.4 to-1.6 V vs.RHE),including 20.4％of FEC2H4(-1.4 V vs.RHE)and 23.9％of FECH4(-1.6 V vs.RHE).By contrast,FEcH4(-1.6 V vs.RHE)in the presence of Cu2O/Cu@C-400 without nitrogen doping is only 2.33％,and no C2H4 is detected.These significant differences in the catalytic behavior can be attributed to the fact that Cu-N is conducive for the stable adsorption of the *CH2 intermediate during the ECR-CO2,thus inhibiting the evolution of H2.These results indicate that the pathway of the ECR-CO2 and its performance can be effectivel regulated by complexing nitrogen with Cu motifs.