Influence of carbon-ion irradiation and hydrogen-plasma treatment on photocatalytic properties of titanium dioxide films

Effects of carbon-ion irradiation and hydrogen-plasma treatment for anatase TiO2 films were examined by decomposition of a dye, and the photoinduced transient charge separation (PITCS) method. For the TiO2 films prepared by anodic oxidation, the photocatalytic activity decreased with increasing carbon-ion dose in a range of 10(13)-10(16) ions/ cm(2). In particular, the activity drastically decreased when the carbon-ion dose was about 10(15) ions/cm(2). From the PITCS measurements, it was found that the transport of holes toward the TiO2 surface was retarded by carbon-ion ldose. After hydrogen-plasma treatments, the activity was lower than that of as-prepared TiO2. For TiO2 films grown by pulsed laser deposition and carried out hydrogen-plasma treatment, on the contrary, the activity was higher than that of pristine TiO2. (C) 2003 Elsevier Science B.V. All rights reserved.