One‐Step Synthesis of CoS‐Doped β‐Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

Abstract

Developing efficient and economical electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction with readily available metals is one of the main challenges for large scale hydrogen/oxygen production. This study reports one step synthesis of cobalt and molybdenum hybrid materials for high performance overall water splitting. The binder‐free CoS‐doped β‐Co(OH)2@amorphous MoS 2+x is coated on nickel foam (NF) to form 3D networked nanoplates that have large surface area and high durability for electrochemical reactions. The catalytic activity of electrocatalyst for hydrogen evolution is mainly attributed to the unsaturated sulfur site of amorphous MoS 2+x. Meanwhile, the CoS‐doped β‐Co(OH)2 plays the major role in oxygen evolution. CoS‐doped β‐Co(OH)2 and aMoS 2+x are strongly bound to each other due to CoSx bridging. This CoSCo(OH)2@aMoS 2+x/NF hybrid exhibits excellent catalytic activity and stability for overall water splitting. For over 100 000 s the cell voltage required to achieve the current density of 10 mA cm–2 is only 1.58 V, which is remarkably low among the commercially available electrocatalysts. The findings open up an easy and inexpensive method of large scale fabrication of bifunctional electrocatalysts for overall water splitting.