Microstructures and photocatalytic properties of nitrogen-implanted titania nanostructured films

Abstract

We report the influence of nitrogen implantation and annealing on the microstructures and photocatalytic properties of a nanostructured titania (TiO2) film. Titania samples were implanted at 40 keV and ion dose range of 1016/cm2 to 4×1016/cm2. From X–ray diffraction (XRD) and transmission electron microscopy (TEM) analyses it was found that the anatase phase of titania was predominated with a tiny brookite and stable at annealing temperatures up to 973 K. The samples showed narrower XRD peaks corresponding to larger mean-grain sizes comparing to the un-implanted titania samples. The SIMS (secondary ion mass spectroscopy) nitrogen depth profile showed a maximum nitrogen concentration at about 70 nm beneath the film surface. The absorption edge of the titania samples as measured using spectrophotometer was found to shift toward longer wavelengths with the increase of ion dose. The experiments of photodegradation of phenol were performed under a UV illumination for the N-implanted titania film which exhibited improved photocatalytic properties with the increase of annealing temperature.