Preparation and Photocatalytic Activities of TiO<sub>2</sub>-rGO Nanocomposite Catalysts for MB Dye Degradation over Sunlight Irradiation

Abstract

This research aims to investigate photocatalytic activities of titanium dioxide (TiO2) incorporated with reduced graphene oxide (rGO) nanocomposite catalysts. These TiO2-rGO photocatalysts were easily prepared through a direct-mixing of TiO2powder suspended in acidic solution under the different amounts of rGO loading (0.25, 0.50, 0.75 and 1.00 wt%). Then, the obtained TiO2-rGO samples were characterized by a several techniques. The results demonstrated that the crystalline phases of all samples are corresponding to pristine TiO2, whereas the characteristic peaks of rGO in the TiO2-rGO nanocomposites could be observed and also well-confirmed by Raman spectroscopy. TEM results showed that the TiO2nanoparticles were well-combined with rGO nanosheets. Moreover, the photocatalytic activities of all TiO2-rGO photocatalyst samples were evaluated by photodegrading of methylene blue (MB) dye solution under natural sunlight irradiation. The results revealed that all TiO2-rGO nanocatalysts exhibited much higher activity than those of the bare TiO2. The improved photocatalytic activity can be attributed to the presence of rGO nanosheets, leading to the decrease of electron (e-) - hole (h+) recombination of TiO2catalyst, increasing charge transfer rate of electrons and surface-adsorbed amount of MB molecules which enhances the photocatalytic activity.