One-step and large scale synthesis of non-metal doped TiO2 submicrospheres and their photocatalytic activity

Without using an external precursor a simple and one-step method for the synthesis of C-doped TiO2 submicrospheres has been developed via hydrolysis of titanium tetraisopropoxide in pure methanol followed by calcination under air at 500 °C. Also, with the addition of d-glucose and NH4OH solution during the hydrolysis process, C- or N-doped and C, N co-doped TiO2 submicrospheres can be prepared by the same method. The size of the submicrosphere was homogeneous ranging from 300 to 400 nm. The resulting submicrospheres were characterized by FE-SEM, TEM, XRD, XPS and UV–vis diffuse reflectance spectroscopy. The C- or N-doped and C, N co-doped submicrospheres showed obvious absorption in the wavelength up to around 650, 500 and 650 nm, respectively. The activity of the photocatalysts was evaluated by the hydroxyl radical formation under visible light irradiation. Finally, the mechanism of sphere formation is discussed.