Design And Synthesis Of Cu-based Catalyst And Study On Its Performance Of Electrochemical CO₂ Reduction

The continuous rise of CO2 concentration in the atmosphere causes global climate change and environmental harm.The use of renewable energy to convert CO2 into fuel or industrial raw materials through photochemistry,electrochemistry,thermochemistry and biochemistry is an important means to close the human carbon cycle.In particular,electrochemical CO2 reduction(ECR)has become a very attractive and promising approach due to its more energy saving and sustainable advantages.However,it is difficult to convert CO2 into C2 and C2+products with higher energy densities because CO2 is a stable linear molecule and ECR process is a multi-step reaction of multi-protonelectron transfer.Copper is the only known metal that can significantly catalyze the conversion of CO2 to multi-carbon products due to the moderate binding strength of*CO intermediate,which enables the further reaction of*CO intermediate to produce C2 and C2+products.Based on this,this paper designed and prepared copper oxide/copper organometallic frame complex to improve the ECR activity and the selectivity of C2H4 products.The specific work is as follows:The CuO/Cu-MOF was synthesized by one-step solvothermal method in N,N-dimethylformamide solution using Cu(NO3)2 and Terephthalic acid as precursors.The composite material is based on a two-dimensional copper organic framework,on which the superfine copper oxide nanoparticles with an average particle size of 2-3 nm are uniformly distributed.In the process of ECR reaction,the main body of the two-dimensional copper organic framework and the ultra-fine copper oxide nanoparticles can synergistically realize the adsorption and activation of CO2 and thus achieve the high selectivity of C2H4.The Faraday efficiency of C2H4 can reach 50%and the total current density is about 14 mA cm-2 in the H-type cell at-1.1 V vs.RHE in 0.1 M KHCO3 electrolyte solution.Under the same conditions,the Faraday efficiency of pure Cu-MOF is 37.6%,and that of pure CuO is 25.5%.The results show that the high C2H4 selectivity of CuO/Cu-MOF complex can be attributed to the synergistic effect of CuO nanoparticles and two-dimensional organic framework of metal copper,which promotes the adsorption activation and C-C coupling of carbon dioxide.Through the work in this paper,we provide an effective strategy to improve the selectivity and activity of electrocatalytic CO2 generation C2H4 through synergistic effect.