Novel hollow core-shell Zn0.5Cd0.5S@ZnIn2S4/MoS2 nanocages with Z-scheme heterojunction for enhanced photocatalysis of hydrogen generation

Abstract

The development of low-cost and efficient metal sulfide photocatalysts through morphological and structural design is vital to the advancement of the hydrogen economy. However, metal sulfide semiconductor photocatalysts still suffer from low carrier separation and poor solar-to-hydrogen conversion efficiencies. Herein, two-dimensional ZnIn₂S₄ nanosheets were grown on Zn_0.5Cd_0.5S hollow nanocages to construct Zn_0.5Cd_0.5S@ZnIn₂S₄ hollow nanocages for the first time. Novel hollow core-shell Zn_0.5Cd_0.5S@ZnIn₂S₄/MoS₂ nanocages with Z-scheme heterojunction structures were obtained by incorporating MoS₂ nanosheet co-catalyst via the solvothermal method. The resulting Zn_0.5Cd_0.5S@ZnIn₂S₄/MoS₂ exhibited unique structural and compositional advantages, leading to remarkable photocatalytic hydrogen evolution rates of up to 8.5 mmol·h^-1·g^-1 without the use of any precious metal co-catalysts. This rate was 10.6-fold and 7.1-fold higher compared to pure ZnIn₂S₄ and Zn_0.5Cd_0.5S, respectively. Moreover, the optimized Zn_0.5Cd_0.5S@ZnIn₂S₄/MoS₂ photocatalyst outperformed numerous reported ZnIn₂S₄-based photocatalysts and some ZnIn₂S₄-based photocatalysts based on precious metal co-catalysts. The exceptional photocatalytic performance of Zn_0.5Cd_0.5S@ZnIn₂S₄/MoS₂ can be attributed to the Z-scheme heterojunction of core-shell structure that enhanced charge carrier separation and transport, as well as the co-catalytic action of MoS₂. Overall, the proposed Zn_0.5Cd_0.5S@ZnIn₂S₄/MoS₂ with heterojunction structure is a promising candidate for the preparation of efficient photocatalysts for solar-to-hydrogen energy conversion.

Keywords: Co-catalyst; Hollow core-shell structure; Photocatalytic hydrogen evolution; Z-scheme heterojunction; ZnIn(2)S(4).