Exploring the effect of boron and tantalum codoping on the enhanced photocatalytic activity of TiO2

Aiming to improve the photocatalytic activity, boron and tantalum co-doped TiO2 nanocrystals were prepared by a sol-gel method. Pure and doped titania samples were characterized by X-ray diffraction (XRD) measurements, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. The results revealed that all the samples have highly crystalline anatase structure, and no any other second phase was observed. It is found that the incorporation of dopants inhibits the growth of TiO2 nanocrystal. Moreover, XPS observations showed that Ta are in the form of Ta5+ while the majority of B species are present at interstitial sites. Finally, photocatalytic activities of all the samples were evaluated by degradation of methylene blue (MB) solutions under simulated solar light irradiation. Ta-doped and (B, Ta)-codoped catalysts exhibit enhanced photocatalytic activities in comparison with pure TiO2, with the codoped sample exhibiting the best photodegradation performance. This indicates that B and Ta co-doping is an effective way to improve photocatalytic performance of TiO2. The catalytic activity of B-doped TiO2 becomes slightly worse than pure TiO2 nanocrystals, which is plausible due to increased charge carrier recombination centers induced by incorporation of boron species. (C) 2015 Elsevier B.V. All rights reserved.