1D/2D CeO2/ZnIn2S4 Z-scheme heterojunction photocatalysts for efficient H2 evolution under visible light

Abstract

The development of a high-efficiency photocatalyst having favorable charge transfer has become an important scientific approach for solar-to-fuel conversion. In this study, the one-dimensional (1D)/2D CeO2/ZnIn2S4 (ZIS) photocatalyst having a Z-scheme heterojunction has been successfully fabricated using the in situ growth of ZIS nanosheets on the CeO2 nanorod surfaces. The optimal H2 production rate of 3.29 mmol g−1 h−1 was achieved with the 15% CeO2/ZIS sample under visible light without any cocatalyst; furthermore, this value was 2.7 and 92.6 times higher than those of pristine ZIS and CeO2, respectively. The remarkable photocatalytic activity can be attributed to the efficient separation of photogenerated carriers as well as the formation of the Z-scheme heterojunction, which maintained the strong reduction of electrons in ZIS for H2 production. The presence of an internal electric field between CeO2 and ZIS has been demonstrated by both density functional theory calculations and Kelvin probe force microscopy. The Z-scheme transfer of photogenerated carriers in the CeO2/ZIS heterojunction has been confirmed by electron paramagnetic resonance spectroscopy and in situ irradiated X-ray photoelectron spectroscopy. This study presents certain insights into the development of efficient Z-scheme photocatalysts for H2 evolution from solar water splitting.