Z-Scheme over all Water Splitting on Rh/K4Nb6O17 Nanosheets Photocatalyst

Abstract

Developing a photocatalysis system to generate hydrogen from water 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 modified K₄Nb₆O₁₇ nanosheets and Pt/WO₃ photocatalysts for H₂ evolution and O₂ evolution with I-/IO₃ - electron mediator under UV light irradiation. The H₂ evolution photocatalyst, Rh/K₄Nb₆O₁₇ nanosheets with a slit like framework, was prepared by exfoliation of and proton exchange reaction. Pt/WO₃ prepared by incipient-wetness impregnation method was used as O₂ evolution photocatalyst. The catalysts were characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy analysis (XPS), and ultraviolet-visible spectroscopy (UV-vis). These catalysts characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectroscopy (UV-Vis). In this study, we developed a facile method of preparing K₄Nb₆O₁₇ nanosheets containing Rh nanoparticles. Our results show that I- concentration and pH of reaction solution have significant influences on the photocatalytic activity. The combination of Rh modified K₄Nb₆O₁₇ nanosheets with Pt/WO₃ achieves a very high photoactivity (H₂: 4240 O₂: 1622 (μmol g^-1 h^-1)).