Rationally Designed Ni–Ni3S2 Interfaces for Efficient Overall Water Electrolysis

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/Ni3S2 microsheets yields an electrode with high electrical conductivity and an abundance of accessible Ni0–Ni3S2 interfaces as active sites for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In 1 m potassium hydroxide, Ni–Ni3S2/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–Ni3S2/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 RuO2 catalysts. To the best of the author's knowledge, Ni–Ni3S2/NF is one of the best non‐precious metal electrocatalysts reported to date for overall water splitting.

Keywords

• bifunctional catalysts
• heterostructured catalysts
• interface engineering
• Ni–Ni3S2
• overall water electrolysis