Lattice-hydrogen cycling mechanism enables pH-universal hydrogen evolution at ampere-level current densities.

Zhang, Yan; Feng, Biao; Tian, Jingyi; Zhou, Shiqi; Zhou, Changkai; Chen, Yiqun; Xia, Xiaoli; Wang, Xizhang et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Controllable supply of hydrogen intermediate across a wide pH range is crucial for electroreduction reactions, but is hindered by pH-dependent hydrogen species formation on conventional catalysts. We report a lattice-hydrogen cycling mechanism that dissociates hydrogen intermediate availability from electrolyte pH. By integrating proton-blocking Ru with thermally-hydrogenated H<sub>x</sub>WO<sub>3</sub>, we create a dynamic hydrogen reservoir, enabling efficient hydrogen supply. In-situ Raman spectroscopy, isotopic labeling, and theoretical simulations reveal the lattice hydrogen in H<sub>x</sub>WO<sub>3</sub> migrates swiftly to Ru active sites via low-energy-barrier pathways, while consumed hydrogen is spontaneously replenished via proton adsorption (acidic) or water dissociation (alkaline/neutral). Consequently, this catalyst achieves a competitive pH-universal performance for hydrogen evolution reaction, with low overpotentials (125 mV acidic, 142 mV alkaline, 219 mV neutral @1 A cm<sup>-2</sup>) alongside 500-hour stability.