Cation Regulates Adsorption–Desorption Behaviors To Promote Electrochemical CO 2 Reduction Reaction

The electrocatalytic CO2 reduction reaction (CO2RR) is a technology to utilize fluctuating renewable energy and close the carbon cycle. Cations play a vital role in interfacial reaction behaviors, which further affect the activity and selectivity of CO2RR. Current insights mainly focus on analyzing cation effects on the reaction kinetics of key intermediates, but a systematic understanding of cation effects cannot ignore the role of adsorption–desorption behaviors in the overall CO2RR performance. In this work, we highlight the effects of K+ on the adsorption and desorption dynamics of both CO2 and CO molecules through ab initio molecular dynamics simulations. We find K+ promotes CO2 adsorption and inhibits *CO desorption dynamically, thereby breaking the dynamic adsorption–desorption equilibrium, which benefits the *CO2 protonation and *CO–CO coupling. The enhanced chemisorption contribution of CO2/CO, arising from the cation-modulated hybridization of molecular orbitals, accounts for the regulation effect on the CO2/CO adsorption–desorption equilibrium. Furthermore, the cation-induced chemisorption of C1 molecules is a widespread phenomenon over various catalysts, including Cu(100), Cu(211), Au(110), Cu/Au(100) single-atom alloy, and Cu–N–C single-atom catalyst. Our study offers another insight into the cation effect on the CO2RR and highlights the significance of cations for interfacial transport of molecules.