Fe(iii) doped NiS2 nanosheet: a highly efficient and low-cost hydrogen evolution catalyst

Abstract

Sustainable hydrogen generation via electrocatalytic/photocatalytic water splitting has been widely regarded as the most promising energy carrier and has attracted extensive attention. However, a considerable hydrogen evolution reaction (HER) always involves the rare noble metals. Herein, we report a new HER candidate, an Fe-doped NiS₂ (Fe–NiS₂) nanosheet, with the performance of high activity and electrochemical stability. We chose the sulfidation of Ni(OH)₂ under mild calcinated temperature for Fe–NiS₂ formation. The theoretical and experimental results suggest that the Fe³⁺ doping into the surface lattice of the NiS₂ (002) facet lowers the activation energy of H₂ generation. The synthesized Fe–NiS₂ sample shows good electrocatalytic HER performance with a low Tafel slope of 37 mV dec⁻¹ and a small overpotential of 121 mV at 10 mA cm⁻². Moreover, Fe–NiS₂ gives considerable stability with a negligible loss of HER value l after a reaction of 1100 min. The Fe–NiS₂ sample is also in situ loaded onto the surface of CdS nanorods to act as a co-catalyst for photocatalytic H₂ generation with the result of 3.2 mmol h⁻¹ g⁻¹ hydrogen evolution under visible light, 46 times higher than with bare CdS. This work can help us to design new electrocatalysts for water splitting; it also provides a good understanding of the hydrogen evolution pathway.