Applied Catalysis B: Environmental, Vol.238, 358-364, 2018
Enhanced photocatalytic NO, decomposition of visible-light responsive F-TiO2/(N,C)-TiO2 by charge transfer between F-TiO2 and (N,C)-TiO2 through their doping levels
Composite type photocatalyst F-TiO2/(N,C)-TiO2 consisted of anatase-type TiO2 with fluorine-doping (F-TiO2) and TiO2 with nitrogen and carbon-doping ((N,C)-TiO2) was prepared by simple physical mixing to exhibit higher visible-light responsive photocatalytic nitrogen oxide (NO) decomposition activity than those of F-TiO2 and (N,C)-TiO2. Transient absorption measurement clarified that the composite possessed longer carrier lifetime compared to that of each material (F-TiO2 or (N,C)-TiO2), resulting in higher photocatalytic activity. In the composite, photoexcited holes and electrons, which are not in impurity level but in valence and conduction band, respectively, should photocatalytically decompose NO, judging from the redox potential of O-2/O-2(center dot-) and the band positions of F-TiO2 and (N,C)-TiO2. The mechanism for higher visible-light photocatalytic activity, or longer carrier lifetime can be explained by charge transfer between F-TiO2 and (N,C)-TiO2 through their impurity levels. The charge transfer should make photoexcited carries spatially separated to enhance the photo catalytic activity.