Research On Catalytic Performance Of Cu-based Materials For Electrochemical CO₂ Reduction

Global warming caused by excessive carbon dioxide emissions is becoming increasingly serious.The use and conversion of carbon dioxide to produce fuels and value-added chemicals,especially through electrochemical reduction,is an effective strategy to alleviate this situation.Electrochemical carbon dioxide reduction(ECR)can be achieved by combining carbon dioxide conversion technology with renewable intrmittent energy sources,such as wind and solar,thus achieving a potential carbon neutral economy.Over the past few years,great efforts have been made to find and design various electrocatalysts for CO2 reduction.Many articles have reported ECR using different catalysts.For example,noble metal catalysts such as gold,silver and palladium can generally reduce CO2 to carbon monoxide(CO),while main group metals catalysts such as tin,lead and bismuth are beneficial to the formation of acidic substances(HCOOH).Copper can effectively reduce CO2 to CO,HCOO-,H2 and hydrocarbons.Considering the uniqueness of Cu in ECR,many studies have been done to improve the selectivity of Cu materials for ECR.(1)In this paper,CuO was modified with metal(Bi,Sb,Cd,Zr)oxides by wet chemical method to form bimetallic oxide composite with highly efficient ECR performance.In particular,CuO-Sb2O3 nanoparticles immobilized on carbon black(CB)can improve ECR selectivity at low electric potentials.The faraday efficiency(FE)of CO is as high as 90.0%(-1 V vs.RHE).Compared with pure coppe'r or pure antimony,the selectivity of CO is greatly improved.The faraday efficiency of the product of CuO-Sb2O3/CB catalyst can be easily adjusted by the interaction of two different components,interfacial contact and microstructured of metal oxides.It is inferred that the enhanced ECR activity is related to the strong interaction between the two metal oxides.Many structural characterization(electron microscope,etc)and electro-catalytic performance studies(electrochemical workstation,etc)have also been carried out.(2)In this study,we have synthesized a representative copper-metal-organic framework Cu(TPA)(D MF)(TPA:1,4-terephthalic acid,DMF:N,N-dimethylformamide)electrocatalyst,which can improve the selectivity of ECR products by adjusting the ultrasonic temperature,different solvents and molar ratio of precursors,etc.Among them,the FE of the hydrocarbon is 72.9%,the FE of ethylene(C2H4)is 50%,and the total current density is 12 mA cm-2.This work proposes an effective strategy for the allocation of MOF-based materials in the energy and catalytic fields,which has the advantage of large surface area and many exposed active sites.