Preparation, characterization of P-doped TiO2 nanoparticles and their excellent photocatalystic properties under the solar light irradiation

Numerous publications have been reported about the doped TiO2 to extend the photoactive wavelength region to visible light for the enhanced photocatalystic properties under artificial visible light irradiation in recent 20 years. Nevertheless except the commercial Degussa P25, the reports about the photocatalysts under the solar light irradiation are very few. Fully utilizing 4% UV light in solar light may be a preferential selection due to its endless energy, free of charge and the faster degradation rate from the UV light than from the visible light. In this study, P-doped anatase TiO2 nanoparticles were conveniently prepared via a conventional sol–gel route. Due to the reconstructed favorable surface structure with the incorporated P–O–Ti bonds and the larger surface area, the P-doped TiO2 nanoparticles exhibited an enhanced photocatalytic activity for the degradation of rhodamine B (RhB) as compared with Degussa P25 and the undoped or N, S-codoped TiO2 under solar light irradiation. Especially, degradation efficiency of RhB over P-doped under solar light is only a little lower than that under UV light in the same irradiation time, suggesting that such constructed photocatalyst could fully utilize solar light and meet the requirement for practical applications. Furthermore some factors including calcination temperature of photocatalyst, initial concentration of RhB, reuse of the photocatalyst, catalyst dosage and P doping contents were also systematically investigated to evaluate the P-doped TiO2 photocatalytic degradation efficiency under the solar light irradiation. This excellent performance endows the as-prepared P-doped anatase photocatalysts potential in purifying wastewater.