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

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. [Figure not available: see fulltext.].