▎ 摘 要
A series of composites consisting of anatase-rutile TiO2 and graphene (TrG) were synthesized by a hydrothermal route. The influence of the amount of graphene oxide on the photocatalytic activity during the degradation of methyl blue was studied. The photocatalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) specific surface area measurements. The results show that as-prepared TiO2 formed in the anatase and rutile phase with a bar structure and it dispersed uniformly over the surface of the graphene sheets. The composites possess higher catalytic activity because of the strong absorption capacity of graphene, the establishment of heterojunctions between rutile and anatase TiO2, the remarkable electrical transport between TiO2 and graphene and the high specific surface areas. The photodegradation performance of methyl blue by the TrG composites under UV light was studied. Our results indicate that the photocatalytic activities of titanium dioxide-graphene composites were higher than those of pure TiO2. We also found that the TrG composites prepared with a loading of 0.8% (mass fraction, w) graphene oxide had the best photocatalytic activity.