Work‐function‐induced Interfacial Built‐in Electric Fields in Os‐OsSe₂Heterostructures for Active Acidic and Alkaline Hydrogen Evolution

Abstract

Theoretical calculations unveil that the formation of Os-OsSe₂ heterostructures with neutralized work function (WF) perfectly balances the electronic state between strong (Os) and weak (OsSe₂ ) adsorbents and bidirectionally optimizes the hydrogen evolution reaction (HER) activity of Os sites, significantly reducing thermodynamic energy barrier and accelerating kinetics process. Then, heterostructural Os-OsSe₂ is constructed for the first time by a molten salt method and confirmed by in-depth structural characterization. Impressively, due to highly active sites endowed by the charge balance effect, Os-OsSe₂ exhibits ultra-low overpotentials for HER in both acidic (26 mV @ 10 mA cm^-2 ) and alkaline (23 mV @ 10 mA cm^-2 ) media, surpassing commercial Pt catalysts. Moreover, the solar-to-hydrogen device assembled with Os-OsSe₂ further highlights its potential application prospects. Profoundly, this special heterostructure provides a new model for rational selection of heterocomponents.