Plasma-catalytic destruction of xylene over Ag-Mn mixed oxides in a pulsed sliding discharge reactor.

Abstract

Plasma-assisted catalytic degradation of xylene was performed in a pulsed sliding dielectric barrier discharge (SLDBD) reactor based on three-electrode geometry over Ag-Mn bimetallic oxides catalysts at room temperature. Experimental results showed that more active species were distributed uniformly in the SLDBD plasma than traditional surface dielectric barrier discharge (SDBD), contributing to higher degradation and energy performance. The xylene degradation efficiency and energy yield in the SLDBD reactor driven by both +pulse (+18 kV) and -DC (-10 kV) were 40% and 2.3 g/kWh higher, respectively, than in the SDBD reactor energized by +pulse alone. The combination of SLDBD plasma with catalysts significantly improved the xylene degradation efficiency and CO2 selectivity than the plasma-only system. The incorporation of Ag into Mn oxide further enhanced its catalytic activity for xylene degradation, and the catalytic activity of Ag-Mn oxides was closely correlated with the Ag/Mn molar ratio. Ag-Mn/γ-Al2O3 (1:2) presented the best performance in plasma-catalysis process, with 91.5% of degradation efficiency and 80.1% of CO2 selectivity at 4.6 W. The higher proportion of surface Oads and better reducibility through the interaction between Ag and Mn species can explain the excellent reactivity of Ag-Mn/γ-Al2O3 (1:2).