Facile Electrodeposition of Amorphous Nickel/Nickel Sulfide Composite Films for High-Efficiency Hydrogen Evolution Reaction

Low-cost preparation of high-efficiency electrocatalysts is challenging the development of electrocatalytic water splitting. Here, amorphous nickel/nickel sulfide composite films with controlled Ni content are prepared directly on nickel foam by adopting the reductant during a facile electrodeposition route, functioning as active hydrogen evolution electrocatalysts. By adopting the reductant during the electrodeposition process, the content of Ni increases in the as-prepared nickel/nickel sulfide composite film, deducing from an energy-dispersive spectrometer. As a result of increased Ni to the optimal ratio, the amorphous nickel/nickel sulfide composite film exhibits remarkable electrocatalytic performance, benefiting possibly the modulated electronic structure, the reduced charge resistance, and the higher effectively electrochemical surface area. In a word, the optimal electrocatalyst presents an excellent catalytic stability and exhibits a small Tafel slope of 79.9 mV·dec–1 and low overpotentials of 43.8 and 134.5 mV to deliver current densities of 10 and 100 mA·cm–2, respectively. The low-cost preparation of the high-efficiency amorphous nickel/nickel sulfide composite film here suggests that the adopted facile electrodeposition method may provide a feasible route for the fabrication of next-generation high-efficiency electrocatalysts for practical applications.