The Synthesis And Performance Of BiVO₄/Graphene Compsite Photocatalyst

Abstract:It has been a research hotspot of environmental and energy fields to realize degrading organic pollutants and producing hydrogen by sun light, with using semiconductor materials. Bismuth Vanadate(BiVO4) has received most attention because of its narrow band gap and high visible-light photocatalytic performance. In this paper, On the basis of the effect of hydrothermal conditions on the structure, morphology and photocatalytic activity of BiVO4, the BiVO4/Graphene(BiVO4/Gr) composite photocatalysts was synthesized by adding graphene oxide(GO) to enhance visible-light photocatalytic performance of BiVO4.BiVO4photocatalysts were synthesized by hydrothermal synthesis method, starting from bismuth nitrate and ammonium metavanadate as raw materials. The effect of reaction condition on the physical properties and photocatalytic performance of BiVO4was investigated, such as hydrothermal temperature, hydrothermal time and initial pH value. And the formation mechanism of different BiVO4was discussed. The results showed that high hydrothermal temperature and low initial pH value are more conducive to the generation of monoclinic BiVO4. polyhedral, flaky, dendritic, Shaqima-like BiVO4crystals were obtained by changing the temperature and initial pH value. In the study, BiVO4with the highest photocatalytic activity can be obtained when reaction temperature is180℃and hydrothermal time is12h with initial pH of5.To improve the photocatalytic performance of BiVO4, the synthesis of BiVO4/Gr composite photocatalyst was studied. The FTIR results showed that the the oxygenic functional groups of GO were removed and deoxided into graphene(Gr) after hydrothermal reaction. It was found that compared with BiVO4, when the feeding amount of GO is17%(wt%of (Bi(NO3)3·5H2O), BiVO4/Gr showed higher photocatalytic activity. The reaction rate constant increased from0.0147to0.0304min-1. and the degradation of methylene blue improved from85%to99%after120min under visible-light. The large specific surface area and good conductivity of Gr can enhance the adsorption of organics and inhibit of recombination of photo-generated electrons and holes, which may attributed the excellent photocatalytic performance of BiVO4/Gr.