Synthesis of Mo-doped TiO2 nanowires/reduced graphene oxide composites with enhanced photodegradation performance under visible light irradiation

Abstract

In this research, anatase type Mo-doped TiO₂ nanowires/reduced graphene oxide (Mo-TiO₂NWs/RGO) composites were successfully synthesized using a one-step alkali hydrothermal method followed by a calcination treatment at 500 °C, in which commercial TiO₂ nanoparticles (Degussa P25) and graphene oxide (GO) were used as the precursors. GO was reduced to RGO during the alkali hydrothermal progress, and Mo was incorporated into the lattice of TiO₂ nanowires (TiO₂NWs) simultaneously. The samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-photoelectron spectroscopy (XPS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-visible diffuse reflectance spectroscopy (DRS). The photocatalytic properties of the prepared catalysts were evaluated for the photodegradation of methylene blue (MB) under visible light irradiation. The results showed that Mo-TiO₂NWs/RGO composites exhibited much higher photocatalytic activity in comparison to the mono-modified or non-modified TiO₂NWs, the photodegradation efficiency of Mo-TiO₂NWs/RGO composites could reach up to 94.1% in 120 min, and no obvious deactivation was observed in the durability experiments. The mechanism of the enhanced photocatalytic activity, which arose from the synergistic effect of the morphology modification, Mo doping and graphene incorporation, was put forward.