| Summary: |
This project seeks to prepare functional nanoparticles and mechanically robust nanocrystalline films with high photocatalytic activity.
Their application will be tested in the industrial production of ceramic tiles aiming to integrate photocatalytic and antibacterial properties in the design of an environmental-friendly product.
Several organic basic compounds used in commercial applications are potentially carcinogenic and mutagenic, and have been referred as priority substances in the Iatest European Directives to receive an increasing attention in indoor air control and in treatment of industrial effluents. Photocatalysis is an active area of research in pollution control, based on the photonic activation of a metal oxide (semiconductor) catalyst by light irradiation. The general mechanisms of photodegradation reactions are comprehensively described in the literature. In brief, illumination of the semiconductor (normally Ti02) with radiation of energy greater than its band gap generates electron-hole pairs, which diffuse to the surface and react with adsorbed species. Undesirable recombination of electron-hole pairs is a serious limitation in photocatalysis efficiency, but can be overcome using titania nanoscaled configurations. With a smaller particle size the rate of surface charge carrier transfer increases, and so does the photocatalytic efficiency.
Nanostructured Ti02 materials, spheroid nanocrystallite, nanoparticles, elongated nanotubes, nanosheets and nanofibers have attracted a vast interest in the last decade. Because of their physicochemical properties they have found application not only in photocatalysis but also in general catalysis, lithium batteries, hydrogen storage and solar-cell technologies. However, the optical capacity and fragility of semiconductor films difficult their use in many commercial applications, where transparent and resistant photoactive coatings are required. Production and testing of nanocrystalline semiconductor films a  |
Summary
This project seeks to prepare functional nanoparticles and mechanically robust nanocrystalline films with high photocatalytic activity.
Their application will be tested in the industrial production of ceramic tiles aiming to integrate photocatalytic and antibacterial properties in the design of an environmental-friendly product.
Several organic basic compounds used in commercial applications are potentially carcinogenic and mutagenic, and have been referred as priority substances in the Iatest European Directives to receive an increasing attention in indoor air control and in treatment of industrial effluents. Photocatalysis is an active area of research in pollution control, based on the photonic activation of a metal oxide (semiconductor) catalyst by light irradiation. The general mechanisms of photodegradation reactions are comprehensively described in the literature. In brief, illumination of the semiconductor (normally Ti02) with radiation of energy greater than its band gap generates electron-hole pairs, which diffuse to the surface and react with adsorbed species. Undesirable recombination of electron-hole pairs is a serious limitation in photocatalysis efficiency, but can be overcome using titania nanoscaled configurations. With a smaller particle size the rate of surface charge carrier transfer increases, and so does the photocatalytic efficiency.
Nanostructured Ti02 materials, spheroid nanocrystallite, nanoparticles, elongated nanotubes, nanosheets and nanofibers have attracted a vast interest in the last decade. Because of their physicochemical properties they have found application not only in photocatalysis but also in general catalysis, lithium batteries, hydrogen storage and solar-cell technologies. However, the optical capacity and fragility of semiconductor films difficult their use in many commercial applications, where transparent and resistant photoactive coatings are required. Production and testing of nanocrystalline semiconductor films are therefore of great interest. In particular, for indoor pollution control, it is extremely important to find suitable preparation and immobilization methods to apply the photocatalytic concept in construction substrates. By this way it will be possible to obtain light induced, self cleaning and non-fogging Ti02 coated materials, destroying any dirt and, more importantly, any pathogens collected in a wall, floor or window. On other hand, even if the treatment of effluents has been reported to be more efficient when suspensions of Ti02 are used, it is noteworthy to consider the impregnation of TiO2 in the wall reactor, avoiding the need of separating the catalyst, thus lowering the cost of the overall process. |