Quantitative Catalyst and Electrolyte Tailoring for Selective Electrochemical CO ₂ Reduction Reaction (CO ₂ RR)

Abstract

Electrochemical reduction of CO 2 (CO 2 RR) to valuable fuels and chemicals is a promising strategy to close the carbon cycle for sustainability benefits. However, the complicated and convoluted reaction pathways lead to a wide product distribution ranging from CO to various hydrocarbons and oxygenates. Here by quantifying the availability of electrolytic active species and the evolution of oxide-derived Cu catalysts based on customized electrochemical and spectroscopic characterization techniques (dynamic micro-IR spectroscopy, enhanced Raman spectroscopy, x-ray absorption/emission/diffraction spectroscopies, electrochemical probing, etc.), we obtain the statistical trends of CO 2 RR selectivity applicable to different reaction systems, enabling a quantitative/semi-quantitative tuning of the catalyst and electrolyte parameters that determine CO 2 RR pathway and selectivity. Especially, as carboxylates are preferred under CO 2 abundant conditions according to the statistics, we achieve record high efficiencies of producing formate/acetate from high-pressure CO 2 on oxide-derived Cu catalysts respectively by tailoring the proton supply, confirming and interpreting the statistical selectivity trends to reveal 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 CO 2 RR towards more insightful statistics and interpretations, as well as on the employment of high pressure electrocatalysis to facilitate stored CO 2 mineralization. Figure 1