Photocatalytic decomposition of NO 2 on TiO 2 films prepared by arc ion plating

Abstract

The structure of TiO 2 prepared by arc ion plating was changed by RF substrate bias from anatase (0 V) through amorphous (−50 V) to rutile (or rutile+anatase) (>−100 V). This tendency was almost independent of arc current (50–80 A). As insulating TiO 2 deposited on the chamber wall, irregular discharge occurred in the chamber. This irregular discharge was enhanced by the substrate bias so that the growth rate was decreased from 1 to 0.6 nm/s and the substrate temperature was decreased from 350°C to 150°C. The oxygen content was increased with decreasing arc current, but the crystallinity at a low arc current of 50 A was low. The decomposition efficiency of NO 2 gas by TiO 2 photocatalyst prepared at arc current of 60 A was high, which was due to the low oxygen deficiency. In particular, anatase structure showed the highest efficiency. Therefore, it is said that structure, composition and crystallinity of the TiO 2 films affect the photocatalytic efficiency.