Controlled synthesis of P-Co3O4@NiCo-LDH/NF nanoarrays as binder-free electrodes for water splitting

Abstract

The design and development of robust and environmentally friendly electrocatalytic materials are of great significance to the hydrogen production industry for the electrolysis of water. A series of P-Co₃O₄@NiCo-LDH/NF materials was firstly successfully synthesized by a hydrothermal method, high temperature calcination and an electrochemical deposition approach when sodium hypophosphite was used as the source of P and Ni(NO₃)₂·6H₂O as the source of nickel and introduced cobalt at the same time. The structure, composition, morphology and electrochemical performance of the P-Co₃O₄@NiCo-LDH/NF electrocatalytic material were determined by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and electrochemical performance testing. It is worth noting that the P-Co₃O₄@NiCo-LDH-2/NF material presents excellent hydrogen evolution reaction performance in 1 M KOH alkaline solution. It only needs an overpotential of 181 mV to drive a current density of 100 mA cm⁻², which is one of the best catalytic activities reported so far. The experimental results and theoretical calculations demonstrate that the electrocatalytic activity of the P-Co₃O₄@NiCo-LDH-2/NF material is attributed to the faster electron transfer rate, exposure of more active sites, optimal water adsorption energy and better electrical conductivity.