Manipulating Electron Redistribution in Ni 2 p for Enhanced Alkaline Seawater Electrolysis.

Developing bifunctional electrocatalyst for seawater splitting remains a persistent challenge. Herein, we propose an approach through density functional theory (DFT) pre-analysis to manipulate electron redistribution in Ni 2 P addressed by cation doping and vacancy engineering. The needle-like Fe-doped Ni 2 P with P vacancy (Fe-Ni 2 Pv) was successfully synthesized on nickel foam, exhibiting a superior bifunctional HER and OER catalytic activity for seawater electrolysis in alkaline condition. As a result, bifunctional Fe-Ni 2 Pv achieve the industrially required current densities of 1.0 and 3.0 A cm -2 at low voltages of 1.68 and 1.73 V, respectively, for seawater splitting at 60 °C in 6.0 M KOH circumstances. The theoretical calculation and the experimental results collectively reveal the reasons for the enhancement of catalyst activity. Specifically, Fe doping and P vacancies could accelerate the reconstruction of OER active species and optimize the hydrogen adsorption free energy (ΔG H* ) for HER. In addition, the active site of Fe-Ni 2 Pv are identified, where P vacancies greatly improve the electrical conductivity and Ni sites are the dominant OER active centers, meanwhile Fe atoms as active centers for the HER. Our study provides a deep insight into the exploration for the enhancement of activity of nickel-based phosphide catalysts and the identification of their real active centers. This article is protected by copyright. All rights reserved.