Heterometal doping on nickel selenide corrugations for solar-assisted electrocatalytic hydrogen evolution

Abstract

Since nickel exhibits good binding energy and is inexpensive, it is widely applied as a hydrogen evolution reaction (HER) electrocatalyst. Among all Ni-based materials, nickel selenide (NiSe) shows a unique electronic structure as a semiconductor with good electrocatalytic activity. Herein, we prepare Co-doped NiSe (Ni_1−xCo_xSe) with a structure of uniform corrugations by one-step chemical vapor deposition. For comparison, Fe-doped NiSe (Ni_1−xFe_xSe) and NiSe are also prepared using the same method. In alkaline electrolyte, Ni_1−xCo_xSe shows great HER performance in terms of low overpotential (93 mV@10 mA cm⁻² and 140 mV@50 mA cm⁻²) and long-term stability. Moreover, with the assistance of solar energy, the overpotential needed for Ni_1−xCo_xSe is reduced, making Ni_1−xCo_xSe better than most reported NiSe-based HER catalysts. On the other hand, the current density of Ni_1−xCo_xSe is 13 mA cm⁻²@93 mV and 63 mA cm⁻²@140 mV with illumination, which is 30% and 26% higher than that without solar illumination assistance, respectively. Therefore, we believe that inducing sunlight to electrocatalytic hydrogen evolution in water splitting could be a supplementary footprint toward the utilization of solar energy.