Degradation of NO using photocatalytic coatings applied to different substrates

This article deals with the degradation of NO present in the air by means of a photocatalytic oxidation process based on TiO2 nanoparticles incorporated in a polymer-matrix-based coating. The experimental set-up consisted of a flow type reactor adapted from the ISO 22197-1 standard. NO2 in the gas phase, and nitrate ions adsorbed on the photocatalytic surface were detected as finals products. Various parameters influencing the NO degradation efficiency were studied: the coating composition, the substrate nature, the initial concentration of NO, the polluted air flow rate and the humidity. Compared to glass, the use of mortar as the substrate enhanced the photocatalytic performance of coatings by reducing the generation of gaseous NO2 as a by-product.