Engineering Ni ^0/δ+ ‐Co ^σ+ Pairs to Facilitate Interfacial Water Restructuring and Promote Volmer‐Heyrovsky‐Dominated Hydrogen Evolution

ABSTRACT

Metal phosphide alloy materials exhibit application potential in alkaline water electrolysis for green hydrogen production. However, interfacial H ₂ O structure, along with protons kinetic behavior at the interface in hydrogen evolution reaction (HER) remain elusive. Herein, we report a site‐substitution‐electronic modulation strategy to construct P‐bridged Ni ^0/δ+ ‐Co ^σ+ pairs in Ni mesh (NM) supported NiCoP (NiCoP‐NM), wherein Co substitution at Ni sites modulates the electronic structure and generates an electron‐rich Ni center. The experiment and theoretical studies reveal that the Ni ^0/δ+ ‐Co ^σ+ pairs redistribute the electron spin orientation at Ni sites, strengthening H* binding, and increasing surface H* coverage, which accelerates Heyrovsky kinetics by facilitating H ₂ release. Additional, Ni ^0/δ+ ‐Co ^σ+ pairs reorganize the interfacial hydrogen‐bonding network and increase K ⁺ concentration in closest ion plane, leading to stronger H ₂ O adsorption (−1.52 vs. −0.96 eV on NiP‐NM) and a lower H ₂ O dissociation barrier (1.59 vs. 1.64 eV on NiP‐NM), thereby facilitating Volmer kinetics via boosting H ₂ O activation. Consequently, NiCoP‐NM achieves outstanding HER performance with an overpotential of only 86.75 mV at 100 mA cm ⁻² , along with stability over 1000 h. This work offers a new strategy for designing metal phosphide alloys that tailor interfacial water structure and proton dynamics for advanced electrosynthesis.