Spatial engineering of photo-active sites on g-C3N4 for efficient solar hydrogen generation

ZnFe2O4 modified g-C3N4 was successfully synthesized by a simple one-pot method. The visible-light-driven photocatalytic hydrogen production activity of g-C3N4 was significantly enhanced due to spatial engineering of the photo-active sites via ZnFe2O4 modification and Pt loading. It is proposed that ZnFe2O4 does not function as visible light sensitizer but as oxidation active sites. In the present ZnFe2O4/g-C3N4 photocatalysts, the photo-induced holes in g-C3N4 tend to transfer to ZnFe2O4 due to the straddling band structures (Type I band alignment), while the photo-induced electrons in g-C3N4 prefer to transfer to the loaded Pt cocatalysts, which can function as reduction active sites for hydrogen production. As a result, the photoinduced electrons and holes in g-C3N4 are efficiently separated by spatial engineering of the photo-active sites, and hence enhanced photocatalytic hydrogen generation activity is obtained.