Lattice Strain Engineering of Ni2 p Enables Efficient Catalytic Hydrazine Oxidation-assisted Hydrogen Production.

Abstract

Hydrazine-assisted water electrolysis provides new opportunities to enable energy-saving hydrogen production while solve the issue of hydrazine pollution. Here, wereport the synthesis of compressively strained Ni2 P as a bifunctional electrocatalyst for boosting both the anodic hydrazine oxidation reaction (HzOR) and cathodic hydrogen evolution reaction (HER). Different from a multistep synthetic method that induces lattice strains by creating core-shell structures, wedevelop a facile strategy to tune strains of Ni2 P via the dual cation-codoping. The obtained Ni2 P with a compressive strain of -3.62% exhibits significantly enhanced activity for both the HzOR and HER than counterpart with tensile strains and without strains. Consequently, the optimized Ni2 P delivers current densities of 10 and 100mA cm-2 at small cell voltages of 0.16 and 0.39V for hydrazine-assisted water electrolysis, respectively. Density functional theory (DFT) calculations reveal that the compression strain promotes water dissociation and concurrently tunes the adsorption strength of hydrogen intermediates, thereby facilitating the HER process on Ni2 P. As for the HzOR, the compression strain reduces the energy barrier of potential-determining step (PDS) for the dehydrogenation of *N2 H4 to *N2 H3 . Clearly, this work not only paves a facile pathway to synthesis lattice-strained electrocatalysts via the dual cations-codoping. This article is protected by copyright. All rights reserved.