Photocatalytic coatings for building industry: study of 1 year of activity in the NOx degradation

Nitrogen oxides (NOx) play a key role in the atmospheric reactions that create ground-level ozone and acid rain. The exploitation of building coatings acting as catalysts for NOx degradation under the effect of solar radiation represents a feasible way of wide applicability to lower NOx concentration in air. A crucial issue for the practical application of photocatalytic coatings is the actual lifetime of the active material. To investigate this aspect, two paints and two plasters (silicate and siloxane resins based) commercially available were formulated with 2% TiO2 Aeroxide P25 and tested in the photocatalytic removal of NOx in air. The results collected over 1 year show how the photoactivity lifetime of these products always decreases with their curing age, being strictly correlated to the formulation of the materials.