PNNL

Abstract

The overpotential for the hydrogen evolution reaction (HER) in aqueous media is highly sensitive to electrolyte concentration. We provide a molecular interpretation of these concentration-dependent HER potential (UHER) trends and introduce a predictive method for water reduction potentials based on the local electrostatic potential of the water oxygen atoms, as determined by their nearest neighbors. This computationally efficient approach requires only molecular dynamics sampling of local configurations and a minimal set of experimental UHER values. Highly extensible across diverse salt compositions, this molecular-level insight into local potentials offers new pathways for designing electrolytes with tailored physicochemical properties.