S-Vacancy-Rich 1T-TaS₂/Cu₂S Heterostructures on Cu Foil for Alkaline Hydrogen Evolution Reaction

Hydrogen evolution reaction (HER) plays a pivotal role in the electrochemical decomposition of water, necessitating the utilization of a catalyst that combines efficiency, durability, and cost-effectiveness. Due to their affordable cost and exceptional activity, transition metal dichalcogenides (TMDs) have garnered significant attention for their potential in HER. Unfortunately, the TMD materials are found inactive in alkaline conditions. Furthermore, for the direct application in HER, the substrates adopted in the synthesis of the TMD materials are still expensive or even precious metals, which restricts their industrial applications. We have successfully batch-synthesized layered 1T-TaS 2 /Cu 2 S heterostructures on industrial copper foil substrates through a simple chemical vapor deposition method. The growth temperature allows convenient control of the concentration of S vacancies in 1T-TaS 2, providing relatively high HER performance in alkaline electrolyte; it exhibits an overpotential of 144 mV. As reported, the performance of 2H-phase TMDs in HER is far from satisfactory due to the inert base planes. Here, utilizing the same approach, we achieved the synthesis of 2H-MoS 2 /Cu 2 S and 2H-WS 2 /Cu 2 S heterostructures, with comparable overpotentials of 169 and 177 mV, respectively, illustrating the universality of the method and HER applications. In addition, its easy availability and low usage price make the industrial-level application more practical.