Intrinsic and Synergy of Carboxyl- and Amine-Bound Water at Electrified Interfaces and Its Contribution to Hydrogen Evolution

Accurately understanding the water structure around multiple groups and their synergistic effect at electrified interfaces has been challenging due to the complexity of the interface. The interfacial chiral symmetry-breaking effect leads to differences in the spatial distribution of functional groups and the consequent water structure, thereby providing a possibility for the accurate analysis of molecular group-associated water. On the basis of this model and combined with surface-enhanced infrared absorption spectroscopy and ab initio molecular dynamics simulation, we have systematically investigated the precise water structure around carboxyl and amino groups, including the influence of carboxyl groups on tetrahedrally coordinated water, the effect of amino groups in tightening the surrounding water organization, and their synergy in directing the first-layer water toward the surface. The presence of methyl groups can enhance the interaction between amino groups and water due to their electron-donating function. Furthermore, we revealed a ligand-induced enhancement in the hydrogen evolution reaction at the single group level. Our research provides a new methodology for obtaining comprehensive insights into the impact of each functional group, how they synergize to regulate the water structure and proton reduction in complex systems, and their contribution to proton-coupled electron-transfer reactions.