In the plot displaying the concentration of NO and NO2 versus reaction time (Fig. 12), we observe the (photocatalytic) abatement of NO,whilst the concentration of NO2 is virtually stable over the time. The final product of NOx abatement is HNO3, which can be easily elutedfrom the catalyst into water [Equation (7)] [87].A similar hypothesis can be made for IPA degradation. Indeed,Palmisano and colleagues proposed the photocatalytic oxidation of IPA to acetone to follow this path [88]: