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

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 H₂O 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||RuO₂. This work establishes a new paradigm for resolving intermediate adsorption competition in multi-electron transfer reactions.