Visually resolving the direct Z-scheme heterojunction in CdS@ZnIn2S4 hollow cubes for photocatalytic evolution of H2 and H2O2 from pure water

The direct Z-scheme heterojunction has been recently emerging as an appealing architecture for photocatalysts design. Its efficiency depends on the interfacial and structural features of the photocatalysts. Herein, the twodimensional ZnIn2S4 nanosheets are grown on the surface of CdS hollow cubes to construct the CdS@ZnIn2S4 hierarchical hollow photocatalysts with chemically bonded interface. The visualized measurements based on spatial-resolved surface photovoltage spectroscopy, combined with other spectroscopic and simulation investigations, clearly disclose that the CdS@ZnIn2S4 hollow cubes constitute a highly efficient direct Z-scheme system. This accounts for the stoichiometric generation of H2 and H2O2 from pure water observed for the CdS@ZnIn2S4 sulfide-only photocatalysts under visible light irradiation with an apparent quantum efficiency of 1.63 % at 400 nm. The present work demonstrates an effective protocol to achieve comprehensive insights into the charge transfer route at semiconductor heterojunction, and offers a viable way for constructing efficient sulfide-only photocatalysts for driving water splitting reaction.

Automated summary

The study successfully constructed CdS@ZnIn2S4 hierarchical hollow photocatalysts with a highly efficient direct Z-scheme system, enabling the conversion of pure water into H2 and H2O2. This work provides an effective approach for building efficient sulfide-only photocatalysts.