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