Influence of photocatalytic paint components on the photoactivity of P25 towards NO abatement

The present work studies the effect of the components of a photocatalytic paint towards the photooxidation of NO. It was used a vinyl high quality exterior paint, modified with photocatalyst P25. NO conversion and selectivity towards nitrate and nitrite were obtained in an experimental photocatalytic reactor that implements essentially the standard ISO 22197-1:2007(E). It is concluded that the paint matrix plays an important role on the photocatalytic activity: pigmentary TiO2 absorbs competitively the UV light, being the most critical component affecting the photocatalytic activity; extenders, such as CaCO3, impair the photoactivity, especially when water is involved in mixing the paint components; organic components mostly affect the performance of the paint during a transient period time of ca. 100–250 h.