D.S. Tsoukleris, G. Psarellis, M.E. Kassalia, N. Friliggou, E.Α. Pavlatou
Nano & Dispersion Coatings, European Interfinish (2015), 26-27 February, Politecnico di Milano, Italy (oral)
In this study, the production of novel doped photocatalyst with self-cleaning and antimicrobial properties under visible light irradiation was investigated. TiO2 is known to possess self-cleaning properties in UV-light, whereas the doping agents were used in order to provide self-cleaning properties under visible light irradiation. For this purpose two different nonmetal dopants were used in order to prepare via sol-gel method nanopowders with band gap lower than 2.5eV. Over the recent years, considerable scientific efforts have been orientated towards improving the photocatalytic action of titanium dioxide. One of the main goals has become the activation of TiO2 under visible light irradiation. To achieve this objective, several works have been conducted concerning the chemical modification of titania. This is attained by the introduction, “implantation” of various elements such as metal-ions e.g. transition metals: Cu, Co, Ni, Cr, Mn, Mo, Nb, V, Fe, Ru, Au, Ag, Pt, as well as non-metal ions: N, S, C, B, P, I, F. On the other hand, in order to improve the photocatalytic activity under visible light, various doping techniques has been explored including precipitation, sol-gel, hydrolysis, sputtering and chemical vapor deposition (CVD) methods. One of the most prevalent synthetic routes for the production of doped nanostructured titania has become the so called solgel process, widely known as hydrolysis-condensation (SOLution-GELation) which falls into the broad class of wet chemistry methods. In this work emphasis has been given to the study of this specific synthesis route, since it has become the most frequently applied synthetic method providing various advantages. The Sol-Gel synthesis of doped titania nanomaterials comprises various steps. Depending on the desired crystal phase composition, particle size and shape regularly an inorganic TiOSO4, TiCl4, or alternatively organic precursor Ti(OR)4 is used. Particular emphasis is placed on exploring the synthetic routes by altering the experimental parameters. All these key parameters are forecast to affect the stability over time and the sequence of preparing the sol to form the stock solution. An important factor is the choice of conditions during the heat treatment. All these factors were key points that affected the final quality, the physical, chemical, optical and electrical properties of the doped titania particles.