Photo-catalytic decomposition of tetrachloroethylene (C2Cl4) by plasma sprayed TiO2 coatings

TiO 2 coatings were prepared on a stainless mesh net by plasma spraying using agglomerated TiO 2 powder. Since TiO2 powders are well known as photo-catalytic materials, the photo-catalytic TiO2 coatings on mesh net are used for purification of water containing tetrachloroethylene (C 2 Cl 4 ). It was found that TiO 2 agglomerated powders could be deposited on mesh net and approximately 35% anatase ratio could be obtained by 400A plasma spraying. It was possible to obtain approximately 100 μm thicknesses on the stainless mesh net substrate when plasma spraying was carried out at 800A, while the coating thickness drastically decreased at 400A. In terms of photo-catalytic properties, retaining the anatase phase ratio in the TiO 2 coatings is essential to achieve photo-catalytic decomposition of 10ppm C 2 Cl 4 solution. It was found that the anatase ratio decreased gradually with increasing arc current and pass count, while the coating thickness increased with increasing arc current. This means that 0.2μm agglomerated powders showed a lower susceptibility to heat effects and provided higher photo-catalytic activity. It was cleared that the anatase ratio had large influence on the photo-catalytic activity. These coatings showed photo-catalytic degradation of C 2 Cl 4 solution. As a result of photo-catalytic experiments, it was shown that tested C 2 Cl 4 solution is decomposed in moderately shorter times, to the extent that 10ppm C 2 Cl 4 was decomposed to less than 1ppm after 7.2ks of 400A plasma sprayed coating. Thermal spraying on stainless mesh net could imply both new applications and possibilities for photo-catalytic degradation of C 2 Cl 4 solution.