Bi2O3 quantum dots decorated anatase TiO2 nanocrystals with exposed {001} facets on graphene sheets for enhanced visible-light photocatalytic performance

Due to its great importance in fundamental research and practical applications, tailored synthesis of anatase TiO2 dominated with highly energetic {001} facets has attracted extensive interest. Here, Bi2O3 quantum dots decorated anatase TiO2 with exposed {001} high energy facets had been firstly prepared on graphene sheets by a simple and feasible strategy using the hydrofluoric acid. During the synthesis process, TiO2 nanosheets were homogeneously decorated with surface enrichment of Bi2O3 quantum dots and graphene was uniformly covered with a large number of Bi2O3/TiO2 composites. The morphologies, structural properties and photocatalytic performance of the resultant Bi2O3/TiO2/graphene composites were investigated and were characterized by X-ray diffraction, scanning electron microscopy. transmission electron microscopy, X-ray photoelectron spectra, UV-vis diffuse reflectance spectrum and photoluminescence spectra. A certain amount of Bi2O3 quantum dots coating on TiO2 nanosheets exhibited significant improvement in photocatalytic degradation of the azo dye Rhodamine B under visible-light irradiation than TiO2 nanosheets, which could be attributed to the extending spectral response from UV to visible area, the enhanced photosensitizing effect of the surface enriched Bi2O3 quantum dots and the strong interaction between Bi2O3 and TiO2. Furthermore, the Bi2O3/TiO2/graphene hybrids could be used as a stable photocatalyst for the highest photocatalytic activity for Rhodamine B degradation, which is ascribed predominantly to the efficient reduction of electron-hole pair recombination in the heterostructures. This investigation likely opens up new possibilities for the development of highly efficient TiO2 based photocatalysts that utilize visible-light as an energy source. (C) 2012 Elsevier B.V. All rights reserved.