Nickel Sulfide Modified NiCu Nanoalloy with Excellent Oxygen Evolution Reaction Properties Prepared through Electrospinning and Heat Treatment

Ni²⁺/Cu²⁺/SO₄²⁻/polyvinyl alcohol precursor fibers with uniform diameters were prepared through electrospinning. Nickel-based composite nanoalloys containing Ni, Cu, and S were prepared through heat treatment in an Ar atmosphere. The experimental results show that the main components of the prepared nanoalloys are NiCu, Ni₃S₂, Ni, and C. The nanoalloys exhibit fine grain sizes about 200–500 nm, which can increase with increasing heat treatment temperature. Electrochemical test results show that the nickel sulfide-modified NiCu nanoalloy composites exhibit excellent oxygen evolution reaction properties, and the oxygen evolution reaction properties gradually improve with the increasing heat treatment temperature. The sample prepared at 1 000 °C for 40 min show a low overpotential of 423 mV and a small Tafel slope of 134 mV·dec⁻¹ at a current density of 10 mA·cm⁻².