Rationally Designed Ni–Ni<sub>3</sub>S<sub>2</sub> Interfaces for Efficient Overall Water Electrolysis
Lishan Peng, Chao Wang, Qing Wang, Run Shi, Tierui Zhang, Geoffrey I. N. Waterhouse
Abstract
High‐performance water‐splitting electrocatalysts are needed by the energy sector for sustainable hydrogen production. Herein, it is demonstrated that the surface decoration of a nickel foam (NF) with porous Ni/Ni 3 S 2 microsheets yields an electrode with high electrical conductivity and an abundance of accessible Ni 0 –Ni 3 S 2 interfaces as active sites for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In 1 m potassium hydroxide, Ni–Ni 3 S 2 /NF exhibits outstanding HER activity (an overpotential of 57 mV at a current density of 10 mA cm −2 ) and similarly impressive OER activity (a low overpotential of only 295 mV at a current density of 20 mA cm −2 ). A water electrolyzer constructed using Ni–Ni 3 S 2 /NF as the HER and OER electrodes exhibits a low cell voltage of only 1.57 V with no obvious performance loss over 30 h, outperforming devices based on expensive Pt/C and RuO 2 catalysts. To the best of the author's knowledge, Ni–Ni 3 S 2 /NF is one of the best non‐precious metal electrocatalysts reported to date for overall water splitting.