NO degradation in air by pigmented photocatalytic plasters: influence of dye concentration

There is a great interest in photocatalytic finishing materials for building applications and several formulations based on white cements are available on the market. Recent architectural trends are however pushing for the development of pigmented photocatalytic coatings. This work has studied the effect of an inorganic dye on the photocatalytic activity of an experimental pigmented plaster. The photocatalytic activity was evaluated as NO degradation in air for various formulations with different dye concentration, demonstrating that even a light coloration can significantly degrade the photocatalytic activity. These results indicate a strong interference between the dye and the photocatalyst that was attributed to the competitive optical absorption in the 300-400 nm wavelength range.