Electric Double Layer Organization of Proton-Transfer Pathways Regulates Alkaline Hydrogen Evolution

Abstract

Abstract Constructing bifunctional catalysts with synergistic interfaces is a promising strategy to overcome the sluggish kinetics of the hydrogen evolution reaction (HER) in alkaline media, where interfacial proton transfer plays a critical role in the reaction kinetics. However, how bifunctional interfaces regulate the interfacial environment governing proton transfer remains poorly understood, particularly at the nanoscale. Here, using well-defined Pt/Ni and Pt/NiO model systems, we integrate spatially resolved scanning electrochemical microscopy, hydration force measurements, and ab initio molecular dynamics simulations across multiple length scales to establish a correlation among local HER kinetics, interfacial electrostatics, and hydration structure. Specifically, the Pt/NiO-derived interface exhibits a lower potential of zero charge (PZC) that is closer to the HER operating potential together with a more interconnected interfacial hydrogen-bond network. In contrast, the Pt/Ni-derived interface exhibits a higher PZC and a less-interconnected hydration structure. These results identify interfacial electrostatics and hydration organization within the electric double layer (EDL) as important factors governing the enhanced HER kinetics at bifunctional interfaces.

The authors' abstract, as published at the source. Journal of the American Chemical Society, 2026 · DOI ↗