Synergy effect of oxyphilic cobalt‑tungsten oxide and copper‑cobalt alloy on water dissociation and hydrogen adsorption for pH-universal hydrogen evolution.

Developing pH-universal hydrogen evolution reaction (HER) electrocatalysts demands the simultaneous optimization of water dissociation kinetics and hydrogen adsorption. Herein, a CuCo/CoWO heterostructure with an area of 600 cm was fabricated via a facile one-step electrodeposition strategy. It only needs 193.8 and 158.1 mV overpotential to drive 1000 mA cm current density in 1 M KOH and 0.5 M HSO, respectively. Moreover, it requires 103.1 mV overpotential to reach 10 mA cm in 1 M phosphate buffered saline (PBS). Remarkably, it exhibits outstanding stability, maintaining over 99.0 % of initial activity after 1000 h of operation at 1000 mA cm in 1 M KOH and 100 mA cm in 0.5 M HSO. Experimental and density functional theoretical (DFT) analyses reveal that the superior selective adsorption capability of oxide component (*HO and *OH) and copper‑cobalt alloy (*H) significantly facilitates water dissociation at the interface. Moreover, the strong Lewis acidity of W further amplifies this effect by enhancing the oxyphilicity of the oxide component, thus resulting in a 40 % decrease in the energy barrier of water dissociation and a 58 % reduction in activation energy for HER. Meanwhile, optimized hydrogen adsorption Gibbs free energy (G) at alloy Co sites also boosts the acidic HER performance. This study presents a promising strategy to develop high-efficiency transition metal-based electrocatalysts for HER across a wide pH range.