Ordered mesoporous films of TiO2 as highly efficient photocatalysts for clean environment
J. Rathousky, V. Kalousek, C. Walsh
J. Heyrovsky Institute of Physical Chemistry, CZ
Keywords: mesoporous film, titanium dioxide, photocatalysis, NOx, self-cleaning surfaces
Abstract:Photocatalytic oxidation is a promising technology for the purification of air. Providing the surfaces of objects with a finish which is photocatalytically active and exhibits stable illumination-induced superhydrophilicity, is a promising route how to render them self-cleaning or easy-to-clean. The aim of the present study is to develop a low-cost and feasible procedure for the preparation of mesoporous films of TiO2 and to optimize their properties with respect to the efficiency in the photocatalytic oxidation of NO and the decomposition of layers of oleic acid, modeling the soiling of the surface. Due to their developed mesoporosity and high crystallinity, these films have been found especially effective when the photodecomposition mechanism is based on the surface-adsorbed reactants. The amount of adsorbed substances is increased due to the large surface area enhances efficiency of their decomposition. Further the mesoporosity will ensure fast transport of O2 and H2O, which are necessary for the photocatalytic degradation of deposits. This transport can be often significantly hindered by the compact layer of the dirt. The preparation procedure itself is based on a template-assisted evaporation-induced self-assembly mechanism and spray-coating technique, which enables to deposit porous films on surfaces of any shape and size and also of controlled thickness.