Regulating the electronic structure of Ni3S2 nanorods by heteroatom vanadium doping for high electrocatalytic performance

Abstract

The exploration of high-performance, inexpensive noble-metal-free electrocatalysts for the oxygen evolution reaction (OER) may be critical for sustainable mass production of renewable energy. In this study, vanadium-doped Ni3S2 nanorod arrays grown on three-dimensional nickel foam (V-Ni3S2/NF) were designed and synthesized by a facile hydrothermal route. Electrochemical measurements showed that the sample with an appropriate amount of V doping (S: V mass ratio of 25:3) exhibited superior OER performance, with an overpotential of 189 mV at a current density of 100 mA cm−2 and a low Tafel slope of 148.87 mV dec−1. The improved catalytic performance can be attributed to the optimization of the electronic structure resulting from enhanced electron transfer due to doping with impurity atoms. Detailed characterization showed that homogeneous V doping changed the morphology of Ni3S2 from nanosheets to nanorods; it also introduced additional catalytic active sites and significantly improved the electrocatalytic activity for the OER. In addition, V-Ni3S2/NF exhibited excellent electrocatalytic stability compared to noble-metal (IrO2) electrocatalysts. The introduction of vanadium suggests a new approach to the design of high-performance OER catalysts in alkaline medium.