High rate deposition of photocatalytic Ti O 2 films with high activity by hollow cathode gas-flow sputtering method

Photocatalytic Ti O 2 films were deposited by a hollow cathode gas-flow sputtering method using two Ti metal targets mounted parallel to each other. The Ar and O 2 flow rates were 3000 and 0 – 50 SCCM (SCCM denotes cubic centimeter per minute at STP), respectively, and total gas pressure during the deposition was maintained at 45 Pa . The highest deposition rate for the photocatalytic Ti O 2 films was 162 nm ∕ min at 30 SCCM of O 2 flow. The as-deposited films and postannealed films, annealed in air at 300 ° C for 1 h , were used to carry out photocatalytic decomposition of acetaldehyde ( C H 3 C H O ) . In particular, the postannealed films showed extremely high photocatalytic activity compared to the photocatalytic activity of films deposited by conventional reactive sputtering.