Photocatalytic air purification: Effect of HNO3 accumulation on NOx and VOC removal

The effect of photocatalytically generated surface HNO3 on NOx and VOC removal activity is investigated using three very different photocatalytic films, namely, P25 TiO2, a commercial exterior paint (produced by STO Gmb) air-purifying curtain fabric (IKEA). required accelerated weathering the cloth UV-preconditioning before exhibiting significant activity. When tested nitric oxide ISO 22197-1:2016, NO ISO, all films exhibited decreasing for with increasing irradiation time, so much that both showed little after 5 h period. In cases loss in was attributed to generation layer HNO3, which found persist at least 15 up 7 days film but could be readily rinsed away. CaCO3 film, fibrous nature IKEA appeared largely eliminate negative days. activities these photocatalysed oxidation acetaldehyde unaffected presence film. relevance results current, products air purification discussed briefly.