Silver-halogen coordination tuned the electronic structure for enhanced CO2 reduction

The electrochemical reduction of CO2 (CO2RR) to CO is a highly promising strategy for addressing both environmental and energy challenges. Identifying catalysts with excellent catalytic performance in CO2RR and facile preparation procedures is currently a hot research topic. Herein, a unique series of halogen‐containing polymorphic AgX (X = Cl, Br, I) nanocatalysts with high CO selectivity, activity, and stability in CO2RR have been synthesized via a one-step wet chemical co-precipitation method. A combination of DFT calculations and electrochemical measurements has illustrated that halogen element doping turns the d-band center of Ag shifting closer to the Fermi level, facilitates the interaction between the *COOH intermediate and the catalyst, lowers Gibbs free energy difference (ΔG) for the rate-determining step, and achieves enhanced CO2RR efficiency (CO faradaic efficiency at 93.24%). This study highlighted halogen doping as a strategy for designing efficient and stable electrocatalysts.