Dual‐Site Synergy in PtRuFeCoNi High‐Entropy Alloys: Mitigating OH*/H* Adsorption Competition for Efficient Alkaline Hydrogen Evolution

ABSTRACT The competitive adsorption between H* and OH* on single active sites is a long‐standing bottleneck limiting alkaline hydrogen evolution reaction (HER) kinetics. Herein, we integrate “multi‐element electronic regulation” with “dual‐site functional partitioning” in a PtRuFeCoNi high‐entropy alloy (HEA) electrocatalyst, which is synthesized via high‐entropy engineering strategy. Driven by electronegativity differences among Pt, Ru, Fe, Co, and Ni, spontaneous electron transfer precisely modulates their d‐band centers of Pt and Ru. This electronic regulation results in that Pt sites activate H ₂ O and adsorb OH*, while Ru sites optimize H* adsorption free energy to ‐0.18 eV for selective H* stabilization. Operando EPR directly captures ·H's “generation‐stabilization‐conversion” dynamics, filling the characterization gap. Complemented by in situ Raman and FTIR, the dual‐site mechanism is validated. PtRuFeCoNi/catalyst exhibits an ultra‐low overpotential of 5.2 mV at 10 mA cm ⁻² , a Tafel slope of 45.6 mV dec ⁻¹ , and 150 h stability in 1 M KOH. For overall water splitting, it achieves 10 mA cm ⁻² at 1.41 V, outperforming Pt/C||RuO ₂ . This work establishes a new paradigm for resolving intermediate adsorption competition in multi‐electron transfer reactions.