Zinc-doped g-C3N4/BiVO4 as a Z-scheme photocatalyst system for water splitting under visible light

A two-step photocatalytic water splitting system, termed a “Z-scheme system”, was achieved using Zn-doped g-C 3 N 4 for H 2 evolution and BiVO 4 for O 2 evolution with Fe 2+ /Fe 3+ as a shuttle redox mediator. H 2 and O 2 were evaluated simultaneously when the doping amount of zinc was 10%. Moreover, Zn-doped (10%) g-C 3 N 4 synthesized by an impregnation method showed superior active ability to form the Z-scheme with BiVO 4 than by in-situ synthesis. X-ray diffraction, UV-Vis spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the samples. It was determined that more Zn–N bonds could be formed on the surface of g-C 3 N 4 by impregnation, which could facilitate charge transfer.