Understanding the Electrochemical Carbon Dioxide Reduction Reaction Mechanism of Lattice Tuning of Copper by Silver Single-Crystal Surface.

Intermolecular interactions and adsorbate coverage on a metal electrode's surface/interface play an important role in CO₂ reduction reaction (CO₂RR). Herein, the activity and selectivity of CO₂RR on bimetallic electrode, where a full monoatomic Cu layer covers on Ag surface (Cu_ML/Ag) are investigated by using density functional theory calculations. The surface geometric and electronic structure results indicate that there is high electrocatalytic activity for CO₂RR on the Cu_ML/Ag electrode. Specifically, the Cu_ML/Ag surface can accelerate the H₂O and CO₂ adsorption and hydrogenation while lowering the reaction energy of the rate-determining step. The structure parameters of chemisorbed CO₂ with and without H₂O demonstrate that activated H₂O not only promotes the C-O dissociation but also provides the protons required for CO₂RR on the Cu_ML/Ag electrode surface. Furthermore, the various reaction mechanism diagrams indicate that the Cu_ML/Ag electrode has high selectivity for CO₂RR, and the efficiency of products can be regulated by modulating the reaction's electric potential.