Persistent fluorescence-assisted TiO₂-xNy-based photocatalyst for gaseous acetaldehyde degradation.

Photocatalytic technologies were utilized to develop an environment-friendly system that is capable of removing and oxidizing organic pollutants from an air stream. A series of long-afterglow phosphors emitting long lifetime fluorescence was adapted to prepared TiO(2)-based composite photocatalysts for the photodegradation of gas-phase acetaldehyde. Although the photocatalytic reaction by an undoped titania (Degussa P25) was stopped immediately after turning off the irradiation light, the long-afterglow phosphor/nitorogen-doped TiO(2) (TiO(2-x)N(y)) composites maintained the acetaldehyde photodegradation ability even after turning off the light for a long time. This novel photocatalytic property may be attributed to the presence of the long-afterglow phosphor, which can reserve the light energy and generate the persistent fluorescence afterward as the light source for the photocatalytic reaction with the visible-light responsive TiO(2-x)N(y). The substitution of the undoped TiO(2) with TiO(2-x)N(y) was essential to use the fluorescence as a light source for photocatalysis. Such a self-fluorescence-assisted system could enhance the performance of photocatalysts for environmental cleanup.