Photocatalytic properties of TiO2-functionalized tiles: influence of ceramic substrate

摘要

To confer self-cleaning properties to ceramic tiles through photocatalytic phenomena, TiO2 is deposited as thin films on their surface. However, photocatalytic properties could be strongly influenced by physico-chemical characteristics of the ceramic support. For this reason, this investigation was aimed to study the influence of porosimetric characteristics of different ceramic tiles on adsorption and photocatalytic activity induced by deposited TiO2 film in the presence of UV light. Experimental data in dark conditions showed that the porosity of the support strongly influenced the adsorption phenomenon of methylene blue (MB). Porosimetric characteristic of samples were tested by Hg intrusion. Higher porosity of the ceramic substrate increased the amount of MB adsorbed. On the contrary, photocatalytic tests have evidenced that a lower porosity of the support determined a higher MB discoloration rate. These results could be explained considering the MB internal diffusion phenomena limit the overall activity inside the porosimetric structure of functionalized tiles.