In-situ spectroscopic probe of the intrinsic structure feature of single-atom center in electrochemical CO/CO2 reduction to methanol

Abstract

While exploring the process of CO/CO₂ electroreduction (CO_xRR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of CO_xRR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm² in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO₂ to methanol is strongly decreased in CO₂RR. In-situ X-ray absorption and Fourier-transform infrared spectroscopies point to a different adsorption configuration of *CO intermediate in CORR as compared to that in CO₂RR, with a weaker stretching vibration of the C–O bond in the former case. Theoretical calculations further evidence the low energy barrier for the formation of a H-CoPc-CO^– species, which is a critical factor in promoting the electrochemical reduction of CO to methanol.

Deciphering the reaction mechanisms of CO/CO2 electroreduction to methanol remains challenging. Here the authors report the higher electron density of single-Co-atom center, along with a different adsorption configuration of *CO, is crucial for promoting the CO electroreduction to methanol.