High Performance Photocatalytic Degradation by Graphene/Titanium Nanotubes Under Near Visible Light with Low Energy Irradiation

In this study, a novel titanium dioxide nanotubes and graphene (GR-TNT) nano-composite was synthesized through a hydrothermal method. The introduction of GR was aimed to reduce the rapid electron-hole recombination of TiO₂ thus improving their phtotcatalytic behavior in real application. The catalysts were characterized by using FT-IR, UV-Vis, XRD, TEM. The degradation results showed that the combined GR and TNT composite could obviously increase the photocatalysis efficiency for Reactive Black 5. The RBk5 removal can reach up to 90% under the near visible light irradiation for 3 h with the irradiation intensity less than 1.0 mW cm⁻² and the 10% GR-TNT dosage of 0.1 g L⁻¹ at original pH (about 5.8). Further experiments were done to probe the mechanism of the photocatalytic reaction catalyzed by GR-TNT composite. EDTA and t-BuOH, which were used as holes and radical scavengers, was used to determine the active oxidative species in the system and the results suggested a holes–driven oxidation mechanism. This study provides a new prospect of using.