Removal of dilute VOCs in air by post-plasma catalysis over Ag-based composite oxide catalysts

This paper reports toluene decomposition with a dielectric barrier discharge (DBD) and a catalyst bed reactor in air at atmospheric pressure. Three Ag-based composite oxide catalysts are used to recycle O radicals for toluene decomposition and ozone decomposition. Toluene is not only oxidized inside the DBD non-thermal plasma (NTP) reactor by active species but also within the catalyst bed reactor via ozone to O radical conversion. Moreover, the DBD generated intermediate byproducts, such as CO, formic acid and formaldehyde, are simultaneously oxidized by the post catalysis. At a DBD specific energy density of 60 J/L, toluene decomposition efficiencies by the DBD and the DBD with the catalyst bed reactor are about 62% and 100%, respectively. In terms of toluene and/or ozone decomposition efficiencies, their chemical reactivity is in the order of NTP + Ag–Mn–O ≈ NTP + Ag–Co–O > NTP + Ag–Ce–O > NTP. The plasma and catalyst hybrid reactor always shows a better performance in comparison with either NTP or chemical catalysis alone.