Strong Built-In Electric Field-Assisted ZnO/ZnIn 2 S 4 S-Scheme Heterostructure to Promote Photocatalytic Hydrogen Production

Photocatalysis is an eco-friendly and significant perspective for generating hydrogen. Our study investigated the ZnO/ZnIn2S4 heterojunction photocatalytic system prepared through hydrothermal technique. Accordingly, the ZnIn2S4 nanofibers loaded with 11 mol % ZnO exhibited the hydrogen evolution rate of about 1998 μmol g–1 h–1, which was 2.6 times higher than the pristine ZnIn2S4. In situ electron paramagnetic resonance results proved the S-scheme photocarrier transport route, and in situ KPFM further characterized the internal electric field between ZnO and ZnIn2S4. The development of S-scheme heterojunctions allows for the spatial segregation and transport of charges by preserving photoexcited holes and electrons with a tremendous redox potential. Furthermore, the photoelectrochemical analysis demonstrated that the S-scheme heterojunction could also be employed for the separation of photoexcited species.