The pivotal effect of the interaction between reactant and anatase TiO2 nanosheets with exposed {0 0 1} facets on photocatalysis for the photocatalytic purification of VOCs

We study the effect of the interaction between reactants and F-free or F-modified anatase TiO2 nanosheets with exposed {0 0 1} facets on photocatalysis. It is found for the first time that the strong interaction between the reactants and TiO2 nanosheets not only reverses the photocatalytic activity of the F-free TiO2 nanosheets and F-modified TiO2 nanosheets, but also conspicuously induces efficient visible photocatalytic activity for the photodegradation of VOCs such as acetone, benzene, and toluene in spite of the large band gap of anatase TiO2 (3.2 eV) and no absorption of the VOCs in visible region. F-modified TiO2 nanosheets have more strong interaction with acetone than F-free TiO2 nanosheets, resulting in the photocatalytic activity of the former higher than the later and the visible photocatalytic activity of the former for the acetone photodegradation. On the other hand, F-free TiO2 nanosheets have more strong interaction with benzene or toluene than F-modified TiO2 nanosheets, resulting in the photocatalytic activity of the former higher than the later and the visible photocatalytic activity of the former for the photodegradation of benzene or toluene. We provide a fundamental insight in the novel and important effect of the interaction on the basis of both DFT calculation and the experimental evidences by photocurrent measurement and fluorescence emission decay. The strong interaction affects both the separation efficiency of the photogenerated charge carriers from TiO2 to the reactants and their band gap characteristics.