Thin films of anatase (TiO2) doped with 1 wt. percent of zinc ferrite (ZnFe2O4) were formed on glass plates by deposition of a sol-gel mixture using an ultra-spinning technique. After the preparation, the TiO2 films with a thickness of 168-232 nm were investigated with respect to their UV absorption capability and photo-degradation of organic molecules. Microscope observations of the surface of TiO2 films showed that they exhibit a micro-granular surface. To test the self-cleaning properties of the doped TiO2 films, a layer of fluoranthene of around 6.5 mg was sprayed over the glass and then exposed to direct or diffuse solar radiation. While the coated-glass transparency was totally recovered at 88 h of direct solar exposure for the undoped anatase film, the covering of fluoranthene on the 1 wt. percent ZnFe2O4-doped TiO2 film was degraded totally at 52 h of exposure time. As complementary experiments, the same glass plates with metal oxide-doped anatase films, after spraying with a similar layer of the organic contaminant, were placed under diffuse sunlight. In a typical experiment, the covering of fluoranthene was degraded almost 100 percent at an exposure time of 48 days and the transparency of glass plates was recovered totally at 55 days of indirect solar exposure. A correlation was found between the weight losses of the solid contaminant and the intensity of the Raman vibration at 672 cm-1. It was found that under diffuse solar irradiation is possible to remove completely a fluoranthene layer generating an expected application of these active surfaces under extreme conditions.
Super-hydrophobic Silver-Doped TiO2 @ Polycarbonate Coatings Created on Various Material Substrates with Visible-Light Photocatalysis for Self-Cleaning Contaminant Degradation