Fabrication Of CuBi Bimetallic Catalysts And Their Performance For Electrocatalytic CO₂ Reduction

In recent years,electrocatalytic CO₂reduction has attracted wide attention.Formic acid is not only a chemical,but also a safe and reliable hydrogen storage carrier.Therefore,electrocatalytic CO₂reduction to formic acid is of great significance.In this paper,a Cu Bi bimetallic catalyst was prepared using commercial foam Cu as a support and Bi as active component,which can be used for electrocatalytic reduction of CO₂to formate.The mechanism of Cu Bi bimetallic catalyst enhancing electrocatalytic performance was investigated.The main research content of this paper is as follows:1.A one-dimensional Cu Bi bimetallic nanomaterial（Cu Bi-4 NWs）was synthesized by chemical oxidation,heat treatment,electrochemical reduction and electrodeposition.The crystal phase and valence state of Cu Bi-4 were characterized by X-ray diffraction,X-ray photoelectron spectroscopy and in situ Raman spectra.The morphology and structure were determined by high resolution scanning electron microscopy and high resolution transmission electron microscopy.2.The electrocatalytic CO₂reduction performance of Cu Bi-4 at different p H values was studied.The results show that formate Faraday efficiency(FE_HCOO^-)of Cu Bi-4 can maintain over 90%within a potential window of 700 m V in neutral environment.At-1.1 V vs.RHE,FE_HCOO^-is 94.5%.At-1.8 V vs.RHE,the maximum partial current density of formate(j_HCOO^-)is 220 m A cm^-2.At-1.3 V vs.RHE,the current density maintains at 145 m A cm^-2.The mechanism of electrocatalytic CO₂reduction enhanced by Cu Bi-4 NWs was further investigated by means of electrochemical active surface area,CO₂adsorption,Tafel slope and in situ Raman spectra.3.The electrocatalytic CO₂reduction performance of Cu Bi-4 in different acidic electrolyte solutions was studied.In p H=4.6,formate Faraday efficiency of Cu Bi-4NWs remained over 90%within a potential window of 600 m V.At-1.4 V vs.RHE,the highest FE_HCOO^-is 94.6%,and the current density can maintain at 160 m A cm^-2at this potential for 55 h.At-1.8 V vs.RHE,j_HCOO^-can reach 225 m A cm^-2.In p H=3.6,formate Faraday efficiency of Cu Bi-4 can maintain over 90%within a potential window of 600 m V.At-1.5 V vs.RHE,FE_HCOO^-is 96.2%.At-1.8 V vs.RHE,j_HCOO^-is 219.3 m A cm^-2.The stability of Cu Bi-4 can remain 110 h at-1.4 V vs.RHE,with a current density of 155 m A cm^-2.In p H=2.6,the highest FE_HCOO^-is 91.4%at-1.6 V vs.RHE.At-1.8 V vs.RHE,j_HCOO^-can reach 214.6 m A cm^-2.