TiO2 films have potential in numerous fields such indoor and outdoor degradation of pollutants, self-cleaning surfaces, smart windows and antifogging mirrors [1,2]. In the present work, transparent and mechanically robust TiO2 films obtained by an innovative electrochemically assisted procedure are presented as effective photocatalysts for indoor and outdoor remediation. The film morphology and thickness were investigated by scanning electron microscopy (SEM), while the optical and surface properties were characterized by means of diffuse reflectance spectroscopy (DRS) and Fourier transform infrared analysis (FTIR), respectively. Mechanical tests (Wolf Wilburn hardness and adhesion tests) proved the high robustness of the layer. The film thickness could be modulated by varying the number of deposited layers (from 1 to 5) without altering the film transparency. The photocatalytic activity of the films was tested towards two different photocatalytic systems: the gas phase degradation of volatile organic compounds, VOCs (ethanol and acetaldehyde) and the degradation of dry stains of long chain organic molecules (fatty acids and siloxanes) adsorbed at the film surface. Ethanol and its main degradation intermediate, acetaldehyde, were chosen as model VOCs since they are important atmospheric pollutants, whose emission are rising owing to the increasing relevance of biofuel usage . Moreover, acetaldehyde is one of the most significant indoor VOCs. Both the disappearance of the pollutant molecule and its complete mineralization (CO2) were followed during photocatalytic tests, by means of a gas-chromatographic system. The degradation of long chain organic moieties adsorbed at the photocatalyst surface were carried out to simulate the staining by fingerprints/oily liquids. The degradation of the organic moieties was monitored by measuring the water contact angle as a function of time. All photocatalytic tests were carried out both under UV and simulated solar irradiation. The titania layers showed excellent photocatalytic activity in both tested systems under UV and simulated solar irradiation. Moreover, no activity loss was observed after repeated degradation tests, as supported also by FTIR and DRS results. The effect of the film thickness on the photocatalytic activity was also investigated. The optimal film thickness was determined as a compromise between the photocatalytic performance and the film optical and mechanical properties. The presented stable and transparent TiO2 layers represent promising materials for photocatalytic windows and coatings. With respect to classical commercial nano-powders, the present robust films reduce the health concerns associated with volatile nanostructured materials .
|Titolo:||Transparent Titania Layers For Indoor Pollution Remediation|
|Data di pubblicazione:||24-giu-2013|
|Settore Scientifico Disciplinare:||Settore CHIM/02 - Chimica Fisica|
|Citazione:||Transparent Titania Layers For Indoor Pollution Remediation / G. Soliveri, D. Meroni, A. Antonello, G. Cappelletti, S. Ardizzone. ((Intervento presentato al 4. convegno International Conference on Semiconductor Photochemistry tenutosi a Praha nel 2013.|
|Appare nelle tipologie:||14 - Intervento a convegno non pubblicato|