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-C3N4 for H-2 evolution and BiVO4 for O-2 evolution with Fe2+/Fe3+ 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-C3N4 synthesized by an impregnation method showed superior active ability to form the Z-scheme with BiVO4 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-C3N4 by impregnation, which could facilitate charge transfer. (C) 2018, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.