Hollow double-shell stacked CdS@ZnIn2S4 photocatalyst incorporating spatially separated dual cocatalysts for the enhanced photocatalytic hydrogen evolution and hydrogen peroxide production

Abstract

Semiconductor-based photocatalytic water splitting is a promising technology to convert solar energy into chemical energy. However, the photocatalytic performance is seriously limited by the low photo-generated charge separation efficiency and high interfacial reaction resistance. Here, a hollow double-shell stacked CdS@ZnIn2S4 system was firstly constructed. The Pt and Co3O4 nanoparticles (NPs) as the hydrogen evolution and the hydrogen peroxide production cocatalysts were loaded on the inner surface and outer surface of CdS@ZnIn2S4 to obtain a novel Pt/CdS@ZnIn2S4/Co3O4 photocatalyst. Compared with the CdS@ZnIn2S4 and dual cocatalysts randomly incorporated CdS@ZnIn2S4/(Pt+Co3O4) sample, this well-designed photocatalyst shows high photocatalytic performance with hydrogen evolution rate and H2O2 production rate reached 8.53 mmol g−1 h−1 and 5.26 mmol g−1 h−1, respectively, which are 3.8 and 1.8 times higher than those of CdS@ZnIn2S4 sample. The enhanced photocatalytic performance can be attributed to the formation of compact heterojunction structure between the ultrathin double shells, which can promote the separation of electron-hole pairs due to its built-in field effect. Besides, the synergistic effect of spatially separated dual cocatalysts are beneficial to the migration of the photo-generated charges to the opposite direction and the suppression of the reverse reaction. This work would pave a way to design unique structure and high-performanced photocatalyts towards photocatalytic water splitting.