Ternary and quaternary thiospinel nanocrystals with adjustable compositions: effects of Band-Gaps and nanostructures on Visible-Light-Driven photocatalytic H2 evolution

Ternary and quaternary structured thiospinel nanocrystals are important materials for energy applications based on their outstanding characteristics such as earth abundant components, non-toxic nature and simple production. In this study, CuNiCoS4, CuCo5S8 and CuCo2S4 nanocrystals have been successfully synthesized via hot injection-method with generalized synthesis conditions and detailed structural, optical and electrochemical characterizations were performed for the first time. The characterization results indicated that the nanocrystals were single phase, nearly stoichiometric composition and a mean size below 10 nm. Moreover, the synthesized nanocrystals have been used for the photocatalytic hydrogen evolution as a catalyst under visible light irradiation. In these reactions, CuNiCoS4 nanocrystals exhibited higher photocatalytic activity and stability than the others. CuNiCoS4 and CuCo5S8 catalyst have firstly been proven as valuable alternatives to CuCo2S4 structure and Platinum in hydrogen evolution reactions and are of particular interest due to lower costs, ease of fabrication and comparable evolution performance.