Enhanced effect of a plasma-irradiated titanium substrate on the photocatalytic activity of a TiO2 film.

To improve the photocatalytic activity of TiO2 film, Ti substrates are irradiated by He ions with different incident ion energy, temperature, and fluence. Anatase TiO2 films are then coated on the plasma-irradiated substrates via chemical vapor deposition followed by calcination. Photocurrent tests and photocatalytic oxidation (PCO) of formaldehyde are used to assess photocatalytic performance. The optimal plasma-irradiated samples showed a four times higher photocurrent and a three fold increase in the rate constant of the PCO reaction compared to the TiO2 coated, untreated control sample. It is found that the enhanced photocatalytic activity and photocurrent are related to the changes of Ti crystal structure and surface morphology through plasma irradiation. [ABSTRACT FROM AUTHOR]