Preparation Of Microstructures On Copper Surface And Their Electrochemical Carbon Dioxide Reduction Performance

Excessive emissions of carbon dioxide（CO₂）lead to the imbalance of the carbon cycle,which has an increasingly bad impact on people and the environment they live in.The conversion of CO₂into high value-added(C₂₊)products is of great significance for the mitigation of CO₂emissions and the realization of artificial carbon cycle.Copper,as the only metal which has been proved to be efficient in electrocatalytic reduction of CO₂to C₂₊,has attracted extensive attention.However,the low surface area and a small number of coordination unsaturated surface active sites make the bulk Cu exhibit poor C₂₊product selectivity.In the process of CO₂electric reduction,the microstructure and crystal surface of copper surface play a key role.Therefore,mechanical grinding method and electrochemical deposition special processing technology were developed in this paper to prepare micro-nano structures on copper surface,so as to achieve high selectivity to C₂₊products in CO₂catalytic transformation.At the same time,the mechanism of efficient CO₂transformation was studied.The research of this paper mainly includes the following two aspects:Micro-nano cavity structure was prepared on the surface of copper foil by mechanical grinding.The grinding process parameters were screened,including the rotating speed of the disc,the counterweight pressure,the type,grinding time,the particle size and grinding mode of the sand paper abrasive particles.Finally,the copper surface was obtained with micro-nano cavity structure.The electrocatalytic CO₂reduction performance test shows that the Cu foil with micro-nano cavity structure has excellent electrocatalytic CO₂reduction performance.The Faraday efficiency for C₂₊products is 65.7%at-1.3 V potential.Combined with XRD,XPS and in-situ infrared characterization,it was determined that the micro-nano cavity structure can limit the interaction between Cu⁺and I^-for a long time,and produce electronic effect with the zero-valent copper in the cavity,which is conducive to the realization of C-C coupling,and ultimately achieve high selectivity of C₂₊products.Microclusters and concave structures were prepared on copper surface by electrodeposition method.The electrodeposition process parameters were mainly selected,including the selection of deposition substrate,deposition time,deposition current density,and the type and concentration of electrolyte in deposition.Finally,the copper surface obtained had microclusters and formed concave structure with the substrate.The results of electrocatalytic CO₂reduction performance test show that the Cu foil with the micro-cluster and concave structure has excellent electrocatalytic CO₂reduction performance.The Faraday efficiency for C₂₊products is up to 80.8%at-1.3 V potential.Combined with contact Angle measurement,EDS and XPS characterization,it was determined that the concave structure on the copper surface can confine Cu⁺for a long time,and realize efficient C-C coupling,thus achieving high C₂₊product selectivity.