Microwave-assisted hydrothermal synthesis of SrTiO3: Rh for photocatalytic Z-scheme overall water splitting

Abstract

Developing a photocatalyst system for solar energy conversion to electric energy or chemical energy is a topic of great interest for fundamental and practical importance. In this study, hydrogen production by a new Z-scheme photocatalysis water-splitting system was examined over Rh-doped SrTiO3 (denoted as Rh:SrTiO3) with Ru nanoparticle as cocatalyst for H2 evolution and BiVO4 photocatalyst for O2 evolution under visible light irradiation, where Co(bpy)32+/3+ was used as electron mediator. The catalysts were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and Ultraviolet-visible spectroscopy. We present a fast and efficient method to synthesize Rh-doped SrTiO3 photocatalyst via microwave-assisted hydrothermal method. Our results showed a significant effect of Ti precursor on morphology of Rh:SrTiO3 prepared by microwave-assisted hydrothermal synthesis. The Ru/Rh:SrTiO3 prepared by TiCl4 precursor showed a nanoporous structure and high photocatalytic activity. The combination of Ru/Rh:SrTiO3 with BiVO4 achieves a high H2 evolution rate (317 μmoL g-1 h-1) and O2 evolution rate (168 μmol g-1 h-1) in 0.5 mM Co(bpy)32+/3+ solution under visible light irradiation.