The ultimate goal of this study was to synthesize core-shell hetero-nanostructures for efficient charge separation during photocatalytic reactions. This is expected to result in increased photocatalytic activity. A core@shell structured CuS@In2S3 was proposed for solar hydrogen production with CuInS2 as an interface between the CuS and In2S3 components. The formation of the CuInS2 interface was confirmed from the XRD and HRTEM analysis. The introduction of the CuInS2 interface resulted in sulfur vacancies on the surface of the photocatalyst, which in turn increased the reactant active sites. In particular, it behaved like an electron trap to retard electron-hole recombination, so that it could eventually improve the photocatalytic activity. The designed CuS@CuInS2:In2S3 photocatalyst exhibited a hydrogen production of 2000 mu mol/g after 10 h. Photoluminescence, photocurrent and IMVS measurements validated the enhanced photoactivity which was due to both the reduced recombination rate between the excited electron and hole pairs (e(-)/h(+)), and the rapid electron transfer in the core@interface: shell structured CuS@CuInS2:In2S3 photocatalyst. (C) 2018 Elsevier B.V. All rights reserved.