Simultaneously optimized CO spillover and electronic structure of relay catalyst for efficient electrochemical C-C coupling

Using renewable electricity to drive the catalytic conversion of CO2 into C2 products is an effective measure to combat climate change and mitigate the greenhouse effect. Since electrochemical CO2 reduction reaction involves multiple proton-electron transfer processes, the selectivity of products especially C2+ products remain undesirable, because it is difficult to optimize both the CO spillover and the electronic structure for an effective C-C coupling. In this study, by adjusting the distance between silver and copper(I) oxide nanoparticles, the CO spillover and the electronic structure of the relay catalyst are optimized simultaneously. Comparing with dissimilar distance, it is found that the relay catalyst with appropriate distance can obtains the best selectivity and activity of the C2 products in this system, with a Faradaic efficiency of 70.7 % at - 0.55 V (vs. RHE), remarkably, maintaining above 55 % from - 0.35 to - 0.95 V (vs. RHE). In situ infrared/Raman spectroscopy is used to characterize the intermediates during the reaction, proving that the high efficiency of CO spillover and optimized electronic structure together promote C-C coupling, which improves the selectivity of C2 products.