Graphene-decorated 3D BiVO4 superstructure: Highly reactive (040) facets formation and enhanced visible-light-induced photocatalytic oxidation of NO in gas phase

摘要

In this study, graphene-decorated 3D flower-like BiVO4 photocatalyst coupling with highly reactive (040) facets was synthesized by a facile alkaline solvothermal route. With the addition of graphene oxide (GO), the size of the subunits composing the 3D flower-like dramatically decreases, while the size of the flower is almost unchanged. Fascinatingly, the introduction of GO in the synthesis medium facilitates the preferential crystal growth of the 3D BiVO4 photocatalyst along its (040) facets. The as-prepared 3D BiVO4/graphene composites with the exposed (040) facets exhibits the enhanced activity in the visible light photocatalytic oxidation (PCO) of NO (similar to 400 ppm), wherein the BiVO4/graphene (2.4 wt%) composite displays the highest photoactivity of PCO of NO. The improved photocatalytic performance was found to be associated with the synergetic effects of the exposed photogenerated electron-rich (040) facets of BiVO4 and the enhanced electronic conductivity caused by the graphene, and more significantly, the interaction between BiVO4 and graphene sheets which reduces the recombination of photoinduced charge carriers. The present study points out that the role of graphene is not only a capping agent to design the highly reactive (040) facets, but also a catalyst promoter for the photocatalytic performance, resulting in an enhanced photoactivity. (C) 2016 Elsevier B.V. All rights reserved.