Self-cleaning glass prepared from a commercial TiO_2 nano-dispersion and its photocatalytic performance under common anthropogenic and atmospheric factors

摘要

Nowadays, a wide range of self-cleaning building materials or colloidal solutions for the fabrication of photocatalytic coatings are already commercially available. However, some practical limitations still restrict their widespread use in the building sector. For example, in normal household conditions, photocatalytic building materials are exposed to factors that can compromise their efficiency or promote the release of nanoparticles to the environment. In addition, most of the building materials are commonly exposed to atmospheric variables that may greatly differ depending on the geographical zone or the season of the year. In this work, TiO_2 films prepared from a commercially available dispersion of nanoparticles were deposited over soda-lime glass substrates. The effects of (ⅰ) NaCl residues from the TiO_2 nano-dispersion; (ⅱ) treatment with model solutions that simulate the environmental and domestic weathering; (ⅲ) the relative humidity and (ⅳ) the substrate temperature on the photocatalytic activity versus stearic acid were evaluated. The obtained results indicate that these films are more efficient in environments with low humidity levels and relatively high temperatures. Therefore, their commercialization in dry and hot geographic zones would enable the best performance. Furthermore, it was found that these materials can be applied in houses without appreciable loss of efficiency, due to weathering from common cleaning agents or atmospheric factors, like rain or acid rain.