Durability of VOC catalysts in solvent emission oxidation

The durability of four noble metal catalysts was investigated in solvent emission oxidation. Mono- and bimetallic catalysts (Pt, Pt–Pd) were supported on γ-Al2O3–La or γ-Al2O3–Ce washcoats and they were aged in industrial conditions for max. 25 months. The catalytic activities (light-off experiments with methane and n-butyl acetate) were determined before and after the ageing to compare the behaviour of catalysts. Catalysts were also characterized by BET and chemisorption measurements as well as with XRD, FTIR and SEM. According to the results, all the catalysts showed excellent stability after the ageing periods and no significant reduction in the activities were observed in the oxidation of n-butyl acetate. However, a small reduction in the activity of the catalysts was observed in the case of methane oxidation, which is related rather to poisoning or fouling of the catalysts than to thermal deactivation. This observation was also supported by other catalyst characterization methods.