Self-Generated Macrochannel-Structure TiO2/g-C3N4 with High Photocatalytic Activity

TiO2/g-C3N4 composites with macrochannel structure were successfully synthesised without using templates by the simple dropwise addition of tetrabutyl titanate containing graphitic carbon nitride (g-C3N4) to a water-ethanol mixed solution, which was then calcined at 400°C. The as-prepared samples were characterised by X-ray diffraction, scanning electron microscopy, and UV-visible absorption spectroscopy. The photocatalytic activities of the samples were evaluated by the photocatalytic degradation of methyl orange in an aqueous medium under visible-light and simulated sunlight irradiation. The results show that the g-C3N4 content in TiO2/g-C3N4 composites plays an important role in the formation of macrochannels. Only samples containing less than 10 wt-% of g-C3N4 exhibit macrochannel structure. TiO2/g-C3N4 composites with macrochannel structure displayed enhanced photocatalytic activity. G-C3N4 content exhibited an obvious influence on photocatalytic performance, and the optimal loading of g-C3N4 was 10 wt-%. The enhanced photocatalytic activity could be attributed to the synergetic effects of the macrochannel structure, the large specific surface area, and the heterojunction between TiO2 and g-C3N4. The main oxidative species responsible for the photodegradation of pollutants were further confirmed by the trapping experiments.