Tunable Nanostructure of TiO 2 /Reduced Graphene Oxide Composite for High Photocatalysis

Abstract

In this study TiO 2 /reduced graphene oxide (TiO /rGO) bipyramid with tunable nanostructure was fabricated by two-step solvothermal process and subsequent heat-treatment in air. The as-synthesized anatase TiO 2 2 nanocrystals possessed morphological bipyramid with exposed dominantly by (101) facets. Polyethylenimine was utilized during the combination of TiO and graphene oxide (GO) to tune the surface charge, hindering the restack of graphene during solvothermal process and resulting in 1 to 5 layers of rGO wrapped on TiO 2 surface. After a further calcination, a portion of carbon quantum dots (CQDs) with a diameter about 2 nm were produced owing to the oxidizing and cutting of rGO on TiO 2 2 . The as-prepared TiO /rGO hybrid showed a highly photocatalytic activity, which is about 3.2 and 7.7 times enhancement for photodegradation of methyl orange with compared to pure TiO 2 2 and P25, respectively. We assume that the improvement of photocatalysis is attributed to the chemical bonding between rGO/CQDs and TiO that accelerates photogenerated electron-hole pair separation, as well as enhances light harvest. 2