Preparation Of Copper-based Nanomaterials And Their Electrocatalytic Properties For Carbon Dioxide And Carbon Monoxide Reduction

With the increase of global greenhouse gas content and the continuous development of catalytic technology,the use of renewable power resources to reduce carbon dioxide(CO₂)into more value-added chemicals and fuels has become a research hotspot in academia.Due to the stable nature of CO₂ molecules,the reaction is slow and the process is complex.A highly efficient and powerful catalyst is needed to facilitate this conversion reaction.Copper has obvious advantages in catalytic carbon dioxide reduction(CO₂RR),Although researchers have made extensive exploration of copper-based materials in recent years,further and more substantial progress is needed to meet the needs of practical industrial applications.In this dissertation,Cu@Sn nanomaterials and Cu@Ag nanomaterials were synthesized by simple deposition method.The synergistic interaction between Cu-Sn and Cu-Ag was used to improve the catalytic performance of the materials.1.The use of electrodeposition method in the preparation of Sn modified copper nanometer materials on carbon paper,after high temperature calcination treatment,better formation of oxide alloy,and then the electrochemical method to reduce the material,finally CO₂RR performance test,after the reduction of Cu@Sn alloy size becomes small and uniform,better play the synergistic effect of metal.The morphology,composition and structure of the materials were analyzed by SEM,XRD,STEM and other characterization methods.The stability of the materials under different voltages and current densities,the Faraday efficiency and stability ampere curve of the materials with different calcination temperatures for CO were tested and analyzed.By changing the plating time,changing the calcination temperature and other conditions to explore the optimal performance of the catalyst,it can be found that when Cu:Sn=14:1,the calcination temperature of 500?material CO₂RR performance is the best.At a potential of-1.8 V(vs.RHE),the Faraday efficiency(FE)of CO can reach 96%,the current density reaches 55 m A·cm^-2,and the material has a strong stability,lasting for 36h.Compared with the Faraday efficiency of CO(65%)catalyzed by Cu,the Sn-modified copper-based nanomaterials have excellent performance in electrocatalytic reduction of CO₂.2.The Cu@Ag nanomaterials were prepared by simple deposition at room temperature,combined with high temperature calcination and electrochemical reduction before performance test.Finally,the electrochemical reduction performance of carbon monoxide(CO)was tested.By using the method of multiple representation information such as the structure and composition of the material was analyzed,and through different calcination temperature CO reduction product of Faraday efficiency,under the condition of different potential under the condition of current density and electric potential under CO reduction product of Faraday efficiency on material performance are analyzed,by changing the calcination temperature,The optimal performance of the catalyst was explored by changing the doping ratio of Cu and Ag atoms.It was found that the Ag doped material still retained the morphology of the original copper nanosheet,but the size was significantly reduced.When Cu:Ag=20:1 and the calcination temperature is 400?,the catalytic performance of the material is the best.The Faraday efficiency of n-propanol can reach(24±1)%and the current density is 7 m A·cm^-2when the potential is-0.5 V(vs.RHE).