Preparation Of Cu₂O/Cu Catalyst By Electrodeposition And Its Electroreduction CO₂ Performance

Replacing traditional fossil energy with renewable energy and clean energy has become an important way to solve the increasingly prominent energy crisis and environmental problems.The combination of renewable energy and new CO₂ electric conversion technology shows a good application prospect.However,the electrochemical reaction process of carbon dioxide is complicated,there are many reaction paths,and there are also thermodynamic and kinetic obstacles,resulting in problems such as poor process selectivity and high reaction overpotential.Therefore,the development of highly selective and highly active catalysts is essential.This article choose the construction of a new copper-based catalyst as the research object,and conducts copper catalyst electrosynthesis and modification research to improve the catalytic selectivity and activity.First,a co-electrodeposition method was used to prepare dendritic core-shell type In-doped Cu@Cu₂O catalyst on carbon fiber paper.Compared with pure Cu and pure In catalysts,In-doped Cu@Cu₂O catalyst significantly improves CO selectivity.At-0.8V vs RHE,the Faradaic efficiency of CO reaches 87.6±2.2%,and the total current density reaches 11.1±0.85 m A cm^-2.Indium doping leads to the redistribution of charge between Cu and In elements and the formation of In-doped Cu₂O shell.Meanwhile,the electrochemical active area of the catalyst is increased and the charge transfer resistance is reduced.The In element doped into the Cu lattice has oxygen affinity,which can stabilize the intermediate*COOH,thereby improving the selectivity and activity of the catalyst.By adjusting the doping amount of the oxygen-philic In element,the ratio of Cu⁺/Cu⁰ was adjusted,and its influence on the selectivity and activity of carbon dioxide electroreduction was obtained.In order to improve the C2 selectivity of the copper catalyst,a two-step electrochemical conversion method was used to reconstruct the metal organic framework to prepare Cu₂O/Cu electrocatalyst.The Cu₂O/Cu₂₅ catalyst obtained by this method has an Faradaic efficiency of ethylene above 31%at-1.2～-1.25 V vs RHE voltage,which is 1.34 times that of the Cu₂O/Cu _NLA electrocatalyst（23.5%）prepared by anodization and twice that of the Cu plate（15.3%）.By adjusting the water/alcohol solvent ratio in the electrodeposition solution,the surface valence state can be adjusted.Combined with Cu LMM Auger spectrum analysis,the relationship between I⁺_Cu/I⁰_Cuand C₂H₄ Faradaic efficiency was established.When I⁺_Cu/I⁰_Cu≥1.4,the Faradaic efficiency of C₂H₄ is approximately a straight line with I⁺_Cu/I⁰_Cu.