Photocatalytic properties of nanostructured TiO2 and TiO2-Al coatings elaborated byHVOF spraying

摘要

In the present study, TiO2 and TiO2-Al composite coatings were prepared by HVOF spraying using reconstitutednanosized feedstock powders prepared via the spray drying technique. In the flame, the powders were injected bytwo methods: internal injection I.e. as in conventional HVOF process and external injection I.e. outside the torchnozzle. The microstructure of the coatings was characterized by scanning electron microscopy and X-raydiffraction. It was found that the amount of anatase in the coatings depends on the nature of the powder and alsoon the type of the injection method. The coatings were tested for their photocatalytic properties regarding theconversion rate of nitrogen oxides. Coatings elaborated by external injection presented a better photocatalyticactivity than those obtained by the conventional HVOF process.