Strong Built-In Electric Field-Assisted ZnO/ZnIn₂S₄ S-Scheme Heterostructure to Promote Photocatalytic Hydrogen...

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.