Low-temperature synthesis of alkalis doped TiO2 photocatalysts and their photocatalytic performance for degradation of methyl orange

In this study, a series of alkalis doped TiO2 (alkalis = Na, K and Rb) photocatalysts were synthesized at low temperature using solvothermal method. Various characterization techniques, such as X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectra (FT-IR), Scanning electron microscopy (SEM), N2 adsorption and UV-vis diffuse reflectance spectra (DRS) spectrophotometer, were employed to investigate the influence of alkali ions on the crystalline phase, grain size, optical absorption and surface functional groups of alkali ion doped TiO2 catalysts. The XRD results indicate that the alkali ion doping restrains the growth of the TiO2 particle size, resulting in a high specific surface area for the alkali ion doped TiO2 materials. The photocatalytic performances of these materials were evaluated using the degradation of methyl orange (10 mg/L) as the model reaction under UV light irradiation. It was found that the photocatalytic activity of the alkali ion doped TiO2 catalysts can be enhanced significantly with the samples doped by 3 wt% alkali ion, which is due to the synergistic effect of pure anatase TiO2 phase structure, small crystallite size, higher surface basic sites and fast electronic transfer rate.