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

B and Ta codoped sample was prepared by a sol-gel method, which exhibits the best photocatalytic performance on degradation of methylene blue solution under a simulated solar light source in comparison with undoped and singly doped TiO2 nanocrystals. The enhancement was tentatively attributed to: (1) the increase of free electron concentrations by substituting Ti4+ with Ta5+ species, as well as the prolonged carrier lifetime due to the complex structures formed by Bint, Ta5+, and doping-induced defects; (2) redshift of optical absorption edge due to the presence of B species at interstitial sites, and (3) reduction of average crystallite size.