Synergistic enhancement of water dissociation and hydrogen adsorption via lattice strain engineering for efficient alkaline hydrogen evolution

The alkaline hydrogen evolution reaction (HER) is crucial for a sustainable hydrogen economy but remains hindered by the slow dissociation of water and the difficult adsorption/desorption of hydrogen intermediates (*H). To address these dual challenges, we introduce a lattice expansion strategy via the incorporation of larger-radius Co 2+ into a NiCoP electrocatalyst. XRD, HRTEM, and XPS analyses reveal a significant lattice expansion of up to 3.2%, which effectively modulates the electronic structure, promoting electron transfer from Co and Ni to P. Electro-response tests further verify that the NiCoP catalyst with optimal lattice expansion control exhibits enhanced water dissociation and an appropriate *H binding capability. These synergistic effects endow the platform with an ultra-low overpotential of 23 mV at −10 mA cm −2 in 1 M KOH. When integrated into an alkaline water electrolyzer, the NiCoP platform requires only a cell voltage of 2.2 V at −500 mA cm −2 and demonstrates superior stability for over 600 h.