Photocatalytic properties of Ta-doped TiO2

This work reports the effect of tantalum (0.1-1 at.% Ta) on the photocatalytic performance of TiO 2 annealed at 1373 and 1673 K in air. It was shown that addition of tantalum resulted in an increase of photocatalytic activity of TiO 2 for the specimens annealed at 1373 K. However, the activity of the Ta-doped TiO 2 specimens annealed at 1673 K was reduced. The effect of tantalum on the photocatalytic performance at 1373 K was rationalised in terms of an increased concentration of titanium vacancies acting as the active surface sites, and increased charge transport. In this work, it was also shown that the band gap reduction due to tantalum incorporation had little effect on photocatalytic performance. The effect of annealing at 1673 K on photocatalytic activity was explained in terms of reduced surface segregation of tantalum.