ИСТИНА

Volatile organic compounds (VOCs) are dangerous air pollutants, which accumulate in the atmosphere and cause photochemical smogformation [1]. Anthropogenic VOCs are mainlyemittedas unburnedhydrocarbonsbydiesel and gasolinevehicles, especiallyundercold start and idlingconditions.A conventionalcatalytic oxidation by molecular oxygen is widely used for VOCremoval; however, this process requires relatively high temperatures. In particular, the oxidation of thelow reactiveC2–C6alkanes is performedabove200–450°C.Recently, ozone catalytic oxidation (OZCO) over Mn/Al2O3has been proposed as an alternative methodfor removal of alkanes, which provides higherefficiency at ambient and near-ambient temperaturesas compared to the conventional oxidation[2]. However, two main problems have been found: 1) significant CO formation; 2) O3-slip.In this study we attempted to solvethese problems by combining Mn/Al2O3(upstream) and Ag/Al2O3(downstream) catalysts in a dual-zone configuration. Our previous studies have shown that though Ag/Al2O3catalysthasinsufficient activity in OZCO of alkanes, itprovides favorable catalytic performancein COoxidation andO3decomposition. Therefore, it wasexpected that a dual-zone Mn/Al2O3||Ag/Al2O3systemcan beeffective for simultaneous OZCO of hydrocarbon, oxidationof CO,and decomposition of residual ozone.