The effect of bulk/surface defects ratio change on the photocatalysis of TiO2 nanosheet film.

The photocatalysis behavior of TiO 2 nanosheet array films was studied, in which the ratio of bulk/surface defects were adjusted by annealing at different temperature. Combining positron annihilation spectroscopy, EPR and XPS, we concluded that the bulk defects belonged to Ti 3+ related vacancy defects. The results show that the separation efficiency of photogenerated electrons and holes could be significantly improved by optimizing the bulk/surface defects ratio of TiO 2 nanosheet films, and in turn enhancing the photocatalysis behaviors. [ABSTRACT FROM AUTHOR]