Hybrids of TiO2 nanobelts modified by graphene: Preparation, characterization, and photocatalytic performance

Photocatalytic composites with high activity have great potential in the purification of dye wastewater. Herein, reduced graphene oxide (rGO) modified TiO₂ nanobelts (TG) hybrids with desirable nanostructures were successfully prepared by regulating the addition amount of Li⁺ via a facile solvothermal process. The results of characterizations indicate that the introduction of two-dimensional (2D) graphene sheet restricts the agglomeration of 1D nanostructures and drives the freestanding growth of TiO₂ nanobelts. Meanwhile, the addition of Li⁺ not only promotes the formation of TiO₂ nanobelts but also affects the distribution of TiO₂ nanobelts on the surface of rGO. The TG-2 synthesized by adding an appropriate amount of Li⁺ exhibits the best photodegradation activity of these samples, even better than commercial P25. The excellent photocatalytic performance of TG-2 is mainly attributed to the effective separation of charge carriers promoted by the synergistic effect between uniform TiO₂ nanobelts and rGO. The trapping experiments of reactive species show that ∙OH may be the dominant species in the photodegradation process. Moreover, the activity of the catalyst does not decrease after five cycles.