Constructing nickel sulfide heterojunctions by W-doping-induced structural transition for enhanced oxygen evolution

Abstract

Developing highly effective non-noble metal-based electrocatalysts is essential for real device applications but remains a challenge. Herein, we report a W-doping-induced phase transition strategy to synthesize W-Ni₃S₂/Ni₇S₆ heterojunctions. The W doping not only regulates the morphology of as-prepared catalysts to construct uniform nanorod arrays but also can induce the appearance of the Ni₇S₆ crystal phase to form W-Ni₃S₂/Ni₇S₆ heterojunctions which can enhance the intrinsic activity of the electrocatalyst. Consequently, W-Ni₃S₂/Ni₇S₆ shows a low overpotential (η1 = 202 mV and η2 = 285 mV in 1.0 M KOH for reaching a current density of 100 and 200 mA cm⁻², respectively), and good stability, and is a promising noble-metal-free OER catalyst.