Easy Synthesis of BiVO4 for Photocatalytic Overall Water Splitting

Developing a photocatalyst system to generate hydrogen from water is a topic of great interest for fundamental and practical importance. In this study, we develop a new Z-scheme photocatalytic system for overall water splitting that consists of Rh/K4Nb6O8 for H-2 evolution, Pt/BiVO4 for O-2 evolution, and I-/IO3- for an electron mediator under UV light irradiation. The oxygen evolution photocatalyst BiVO4 was prepared by the microwave-assisted hydrothermal method. The method is fast and simple, as compared to conventional hydrothermal synthesis. The catalysts were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and UV-visible spectroscopy. The photocatalytic water splitting is investigated in (i) aqueous AgNO3 as sacrificial electron scavengers and (ii) a Z-scheme photocatalytic water splitting system. The BiVO4 photocatalysts prepared by the microwave-assisted hydrothermal method not only showed a very high oxygen evolution rate (2622 mu mol g(-1) h(-1)) of water splitting reaction in an aqueous AgNO3 solution but also achieved a high H-2 evolution rate (340 mu mol g(-1) h(-1)) and O-2 evolution rate (172 mu mol g(-1) h(-1)) in a Z-scheme overall water splitting system.