A study of spherical TiO₂/g-C₃N₄ photocatalyst: Morphology, chemical composition and photocatalytic performance in visible light

In this study, a novel spherical TiO₂/g-C₃N₄ hybrid was obtained by facile solvothermal synthesis. The morphologies were characterized by field emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM). The structural properties of TiO₂/g-C₃N₄ were analyzed by X-ray diffraction (XRD) and the (002) peak shifted slightly in g-C₃N₄ revealed the effect of TiO₂ on the interlayer distance of g-C₃N₄ due to the tight contact between TiO₂ and g-C₃N. The chemical compositions of TiO₂/g-C₃N₄ were analyzed by Foutier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the tiny characteristics were deeply analyzed for exploring carbonylation of tri-s-triazine units due to TiO₂ as catalyzer. The thermal stability of TiO₂/g-C₃N₄ hybrid was carried out by thermogravimetric differential scanning calorimetry (TG-DSC), and the degradation temperatures of g-C₃N₄ obviously decreased under TiO₂. UV–vis diffuse reflectance spectroscopy (DRS) was performed to investigate the absorption bandgap energy, while photoluminescence (PL) indicated the lower recombination of photo-generated charges for TiO₂/g-C₃N₄ hybrids. The photocatalytic activity and stability of the TiO₂/g-C₃N₄ hybrid was evaluated by degradation of Methyl Blue under visible light irradiation. The result indicated that the optimum mass ratio of TiO₂/g-C₃N₄ of 12:1 was 7.3 times, 12.5 times and 87.5 times as high as that of Degussa P25, nanosheet TiO₂ and powder g-C₃N₄, respectively, which exhibited an excellent photocatalytic performance. Recycling test of H 12-1 shows still quite a high catalytic performance after the continuous irradiation of 600 mins. At the end of article, a possible photocatalytic mechanism was discussed based on the experimental results.