Electrochemical potential-driven water dynamics control CO2 electroreduction at the Ag/H2O interface

A molecular-level understanding of the catalyst-electrolyte interface under realistic operating conditions remains a central challenge in electrocatalysis. In particular, the role of the electrochemical potential in modulating interfacial solvation, and its consequences for CO2 electroreduction, has yet to be fully elucidated. Here, using machine learning-accelerated molecular dynamics simulations, an explicit solvent model within the grand canonical DFT framework, and enhanced sampling techniques, we systematically investigate the impact of the working potentials on CO2 reduction process at the Ag(111)/H2O interface. Our results reveal that the applied potential significantly reshapes the orientation of interfacial water and modulate the strength of hydrogen-bond network. This collective solvent response to the electric potential plays an important role in stabilizing reactive intermediates, regulating reaction kinetics, and facilitating key steps such as proton transfer and hydroxide diffusion. These findings underscore the critical role of solvent dynamics in CO2 reduction, highlighting the importance of simulating electrochemical reactions under realistic operating conditions. Rather than acting as a passive background medium, the solvent emerges as a dynamic, potential-sensitive participant that plays an active role in the catalytic process. Molecular insight into catalyst-electrolyte interfaces under realistic conditions is a key challenge in electrocatalysis. Here, the authors reveal that the applied potentials reshape interfacial water dynamics, which actively regulates elementary steps in CO2 electroreduction.