NiCo2S4 microspheres grown on N, S co-doped reduced graphene oxide as an efficient bifunctional electrocatalyst for overall water splitting in alkaline and neutral pH
Haoquan Li, Long Chen, Pengfei Jin, Yafei Li, Jianxiang Pang, Juan Hou, Shanglong Peng, Gang Wang, Yulin Shi
Abstract
It is of vital importance to design efficient and low-cost bifunctional catalysts for the electrochemical water splitting under alkaline and neutral pH conditions. In this work, we report an efficient and stable NiCo2S4/N, S co-doped reduced graphene oxide (NCS/NS-rGO) electrocatalyst for water splitting, in which NCS microspheres are composed of one-dimentional (1D) nanorods grown homogeneously on the surface of NS-rGOs). The synergetic effect, abundant active sites, and hybridization of NCS/NS-rGO endow their outstanding electrocatalytic performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in both alkaline and neutral conditions. Furthermore, NCS/NS-rGO employed as both anode and cathode in a two-electrode alkaline and neutral system electrolyzers deliver 10 mA/cm2 with the low cell voltage of 1.58 V in alkaline and 1.91 V in neutral condition. These results illustrate the rational design of carbon-supported nickel-cobalt based bifunctional materials for practical water splitting over a wide pH range.