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

The electrocatalytic CO 2 reduction reaction (CO 2 RR) 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 CO 2 RR. 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 CO 2 RR performance. In this work, we highlight the effects of K + on the adsorption and desorption dynamics of both CO 2 and CO molecules through ab initio molecular dynamics simulations. We find K + promotes CO 2 adsorption and inhibits *CO desorption dynamically, thereby breaking the dynamic adsorption–desorption equilibrium, which benefits the *CO 2 protonation and *CO–CO coupling. The enhanced chemisorption contribution of CO 2 /CO, arising from the cation-modulated hybridization of molecular orbitals, accounts for the regulation effect on the CO 2 /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 CO 2 RR and highlights the significance of cations for interfacial transport of molecules.