A three-dimensional coral-like Zn,O-codoped Ni3S2 electrocatalyst for efficient overall water splitting at a large current density

Abstract

The synergistic achievement of geometrical optimization and electronic structure adjustment of electrocatalysts is significant to accelerate the efficiency of overall water splitting. Herein, we report a three-dimensional coral-like Zn,O-codoped Ni₃S₂ nanostructure grown on nickel foam (denoted as ZO-Ni₃S₂/NF) by a facile solvothermal method. We show that the introduction of Zn²⁺ can not only trigger the generation of a three-dimensional coral-like nanoarchitecture of Ni₃S₂/NF with a larger catalytically active area, but also increases the number of active Ni³⁺ sites in ZO-Ni₃S₂/NF, which enhances the adsorption capacity of intermediates in the oxygen evolution reaction (OER) process. Moreover, the O-doping endows Ni₃S₂ with improved intrinsic electronic conductivity and thus facilitates fast charge transfer during the hydrogen evolution reaction (HER). As expected, ZO-Ni₃S₂/NF exhibits excellent electrocatalytic performance, requiring only 235 mV and 450 mV to deliver 500 mA cm⁻² for the HER and OER, respectively. The findings in our work provide new insights for the development of highly active and stable noble-metal-free electrocatalysts at high current density for industrial hydrogen fuel production.