Photocatalytic activity of anatase-containing facade coatings

The photocatalytic activity of a nano-anatase-containing paint has been studied. It was found that after a certain period of initial UV irradiation, the photocatalytic activity of such a paint significantly increases. To understand the underlying mechanisms, the pigment volume concentrations (PVCs) were varied in different ways, e.g. by varying the content of the inorganic filler, or by adjusting the content of the polymeric binder. The results were compared with the photocatalytic activity of a commercially available paint. The formulations which exhibit a good compromise between photocatalytic activity and other essential paint properties are discussed. The effect of relative humidity on the photocatalytic activity was also measured and is commented upon.

► A standard paint formulation was treated with photocatalytic anatase nanoparticles.
► Pigment volume concentration (PVC) of such paints was systematically changed.
► After activation, the photocatalytic activity of paints was ca. 80 ppm h−1.
► The gloss and hiding power were acceptable after adding 2.5–5% of rutile.
► The photocatalytic activity was found to decrease with increasing relative humidity.