Decomposition of organic dyes with sputtered TiO2 photocatalytic films

This article reports on the photocatalytic activity of transparent crystalline TiO2 films deposited on unheated glass substrates at low substrate surface temperature Tsurf≈180°C using a dual magnetron operating in bipolar asymmetric mode in Ar+O2 mixture and equipped with Ti(99.5) targets of 50 mm in diameter. The photocatalytic activity (PCA) of TiO2 films was characterized by the photocatalytic decomposition rate of two organic dyes (Acid Orange 7 and Methylene Blue). It was found that the Acid Orange 7 is more convenient for the testing of PCA activity of TiO2 films due to its higher stability. It was shown that (i) dual magnetron sputtering is suitable for a low temperature sputtering of thin TiO2 photocatalysts, (ii) thin TiO2 films sputtered at temperatures Tsurf≈180°C exhibit high PCA which strongly increases with increasing film thickness, and (iii) TiO2 films prepared at high values of pT and pO2 have anatase structure and highest PCA