Selective catalytic reduction of NOxin dielectric barrier discharge plasmas

Abstract

This article reports observations of significant synergistic effects between dielectric barrier discharge (DBD) plasmas and Cu-ZSM-5 catalysts for C 2 H 4 selective reduction of NO x at 250 °C in the presence of excess oxygen by using a one-stage plasma-over-catalyst (POC) reactor. With a reactant gas mixture of 530 ppm NO, 650 ppm C 2 H 4 , 5.8% O 2 in N 2 , GHSV = 12 000 h -1 and input discharge energy density of 155 J L -1 , the pure catalytic, pure plasma-induced (discharges over fused silica pellets) and plasma-catalytic (in the POC reactor) NO x conversion percentages are 39%, 1.5% and 79%, respectively. A moderate plasma enhancement of NO x reduction by C 2 H 4 was also observed in a two-stage plasma-followed-by-catalyst (PFC) reactor consisting of a discharge stage filled by fused silica pellets and a Cu-ZSM-5 catalyst stage.