Electron-withdrawing functional ligand promotes CO 2 reduction catalysis in single atom catalyst

Electrochemical carbon dioxide reduction reaction (CO 2 RR) powered by renewable electricity offers an attractive approach to reduce carbon emission and at the same time produce valuable chemicals/fuels. To design efficient CO 2 reduction electrocatalyst, it is important to understand the structure-activity relationship. Herein, we design a series of single Co atoms electrocatalysts with well-defined active sites electronic structures, which exhibit outstanding CO 2 RR activity with controllable selectivity to CO. Experimental and density functional theory (DFT) calculation studies show that introducing nitro (amino) ligand next to single Co atom catalytic center with electron-withdrawing (electron-donating) capability favors (hinders) CO 2 reduction catalysis. This work provides an in-depth understanding of how functional ligand affects the splitting of transition metal 3d electron orbital, thereby changing the electron transfer from transition metal active site to CO 2 , which is closely related to the Gibbs free energy of the rate-determining step (CO 2 +e − +*→*CO 2 − ).