Photocatalytic properties of oriented, (001) faceted anatase TiO2 films

The photocatalytic properties of oriented, (001) faceted anatase films were investigated\ud using terephthalic acid (TA) as a hydroxyl radical (???OH) trapping molecule and\ud rhodamine B and methylene blue as model dye compounds. The films were prepared\ud using a hydrothermal route onto gold and Pyrex substrates. Characterization by x-ray\ud diffraction (XRD) and Raman spectroscopy shows that the films are oriented anatase with\ud [001] direction. Scanning electron microscopy (SEM) shows that the films are\ud poly crystalline, single-crystal thick with exposed (001) facets. UV-A photolysis of Ti0 2\ud films produces 'OH in TA solution and this is dependent on available surface area. After\ud surface area measurements are made using atomic force microscopy (AFM) and defect\ud count analysis, it is determined that the anatase films generate more "OH than a reference\ud material, P-25. In the absence of dissolved O2 , formation o f ???OH by anatase films is lower\ud suggesting that ???OH formation by these films occurs via a photo-reductive mechanism.\ud However, with P-25 films, the presence of O2 has no effect on ???OH formation. Both\ud anatase and P-25 films are capable of degrading rhodamine B and methylene blue under\ud UV-A light and this is dependent on available surface area