Authors: M.V. Diamanti, S. Codeluppi, A. Cordioli, MP. Pedeferri
Affilation: Politecnico di Milano, Italy
Pages: 1012 - 1015
Keywords: thermal treatment, titanium oxide, photoactivity
Nanocrystalline TiO2 is one of the most important and used photocatalysts because of the excellent efficiencies of conversion of chemical species, and its chemical stability. Its photocatalytic properties are activated only by UV light; nevertheless, the oxide band gap can be modified in order to shift light absorption towards visible light. Through anodization, semicrystalline oxides can be produced, containing anatase or rutile nanocrystals; moreover, by applying a thermal treatment the amorphous oxide can be partially converted into anatase or rutile. In this work, the thermal oxidation of titanium was explored, either as an alternative to anodization or as a means to modify the structure of the anodic oxide; aim was the alteration of the band gap of TiO2. The thermal oxidation of titanium was proved to be a powerful process to induce the formation of photoactive phases in the oxide nanolayer, and therefore to create a photocatalytic oxide that can find application in air purification or wastewater treatment, both for external uses and indoor applications where UV light cannot be used. Moreover, the optic characteristics of these thin films cause the generation of interference colors on the surfaces, an additional value of particular interest for design applications.