Preparation of N-Doped TiO_x Films as Photocatalyst Using Reactive Sputtering with Dry Air

Abstract

Pale yellow N-doped TiO_x films on the glass substrate were prepared by RF magnetron reactive sputtering of Ti target in a mixed gas of argon and dry air. The characteristics of the N-doped TiO_x films were studied by SEM, XRD, UV–Vis spectrophotometer and XPS. The photocatalytic ability was evaluated by degradation of NO gas. The air flow ratio has a significant effect on the produced phase and the bonding states of Ti, O and N, resulting in the variation of the optical property and photocatalytic ability. The large amount of N atoms doped and oxygen deficiency are detrimental for photocatalysis, and N bonding states may not be the major contributing factor for the photocatalysis. It is suggested that the coexistence of N₂ gas with O₂ gas shifts the TiO₂ formation boundary towards the low oxygen concentration, which leads to various N (N oxide) doping states on N-doped TiO_x film.