Fe_(2)P nanoparticles embedded on Ni_(2)P nanosheets as highly efficient and stable bifunctional electrocatalysts for water splitting

摘要

It is urgent to develop highly efficient,stable and low-cost bifunctional electrocatalysts for overall water splitting.Herein,an iron-nickel phosphide(Fe_(2)P/Ni_(2)P)heterostructure,constructed by Fe_(2)P nanoparticles embedded on Ni_(2)P nanosheets,is strategically fabricated on nickel foam via a facile process.As a bifunctional electrocatalyst,the Fe_(2)P/Ni_(2)P heterostructure delivers a very low overpotential of 64 m V(or 185m V)to reach current density of 10 m A cm^(-2)for hydrogen(or oxygen)evolution reaction.When simultaneously employed as both the anode and cathode electrodes,it demonstrates an ultralow cell voltage of1.49 V@10 m A cm^(-2)for full water splitting with nearly 100%Faradaic efficiency,and superior long-term stability even over 100 h.Density functional theory calculations manifest that a strong heterointerface interaction could cause electron redistribution near the Fe_(2)P/Ni_(2)P heterointerface and optimize theΔG_(H)*of P sites,thus enhancing catalytic activity.Additionally,the 3D porous heterostructure is beneft to expose rich active sites and facilitate ion diffusion and gas bubble release,thus promoting the catalytic performance.This work opens up a new strategical approach for rational design of metal phosphide-based heterostructures as highly efficient and stable bifunctional electrocatalysts for water splitting.