The fabrication of Co:ZnS/CoS2 heterostructure nanowires with a superior hydrogen evolution performance

Abstract

The development of highly active, low-cost and earth-abundant non-noble transition metal electrocatalysts for the hydrogen evolution reaction (HER) is a significant challenge in the sustainable energy field. Herein, we reported ultrafine Co:ZnS/CoS₂ heterostructure nanowires (NWs) prepared by the one-step hydrothermal method for high-efficiency HER. The Co:ZnS/CoS₂ heterostructure nanowires presented superior HER activity with an overpotential (η) of 78 mV at the current density of 10 mA cm⁻² and a Tafel slope of only 56 mV dec⁻¹, which was smaller than that obtained in previous reports for similar materials. Furthermore, the overpotential increased only by 5 mV after 1000 cycles, and the structural change was not obvious. Our theoretical and experimental results indicated that the formation of the Co:ZnS/CoS₂ heterostructure showed excellent charge transport kinetics, thus significantly improving its HER performance. Such ultrafine Co:ZnS/CoS₂ heterostructure nanowires may be a promising substitute to noble metal electrocatalysts for water splitting.