(5d) Quantitative Catalyst and Electrolyte Tuning Towards Selective Electrosynthesis Using CO2

Electrochemical reduction of CO₂ (CO₂RR) to valuable fuels and chemicals is a promising technique to close the carbon cycle. However, the high complexity in the reaction mechanism leads to a wide product distribution ranging from CO to hydrocarbons, alcohols, carboxylates, and many other oxygenates. Here by experimentally quantifying the availability of electrolytic active species and the evolution of oxide-derived Cu catalysts using various customized electrochemical and spectroscopic characterization techniques, we obtain a statistical trend of CO₂RR selectivity applicable to different reaction systems, allowing a quantitative/semi-quantitative tunning of the catalyst and electrolyte parameters that determine CO₂RR pathway towards desired kinds of product. Especially, as carboxylates are preferred under CO₂ abundant conditions according to the statistics, we achieve record high efficiencies of producing formate/acetate from high-pressure CO₂ on oxide-derived Cu catalysts, confirming the reliability of statistical reaction selectivity and indicating a unique bidentate carboxylate pathway. Further efforts in this direction are put into the development of advanced high-throughput/automation electrolysis and characterization methods to expand the database of CO₂RR towards more insightful statistics, as well as on the combination of high pressure electrocatalysis with geochemical process in facilitating the mineralization and conversion of stored CO₂.