Role of process conditions on the properties of immobilized TiO2 films on stainless steel prepared using combined alkoxide sol-gel and colloidal suspension preparation methods

COLL 449

Yongjun Chen and Dionysios D. Dionysiou. Department of Civil and Environmental Engineering, University of Cincinnati, 765 Baldwin Hall, Cincinnati, OH 45221-0071
In this study, nanoparticle-based TiO2 photocatalytic coatings on stainless steel supports have been prepared by a novel combination of the alkoxide sol-gel and the colloidal suspension preparation routes followed by dip coating and heat-treatment procedures. In this approach, a highly active photocatalyst, Degussa P-25, is incorporated in a titanium tetraisopropoxide-based sol. The study includes a detailed investigation of the effect of several process parameters on the morphology, crystal composition (anatase, rutile), elemental composition and purity, mechanical properties, hydrophilicity and photocatalytic activity of TiO2 coatings. These include the composition of the sol (composition of the solvent, concentration of P-25), viscosity of modified sol, calcination temperature and duration, and surface roughness of support material. The results are discussed with respect to the size and crystal composition of the primary nanoparticles of the film, particle aggregation in the film, film thickness and surface roughness, and film interparticle porosity. Diffusion of species of the stainless steel support towards the catalytic film during heat treatment will also be discussed.