Selective catalytic reduction of NO_x in dielectric barrier discharge plasmas

¹ Laboratory of Plasma Physical Chemistry, Box 288, Dalian University of Technology, Dalian 116024, China
² State Key Laboratory of Material Modification by Ion, Electron and Laser Beams, Dalian University of Technology, Dalian 116024, China

Corresponding author: labplpc@dlut.edu.cn

Received: 6 July 2004
Revised: 8 December 2004
Accepted: 17 December 2004
Published online: 4 March 2005

Abstract

This article reports observations of significant synergistic effects between dielectric barrier discharge (DBD) plasmas and Cu-ZSM-5 catalysts for C₂H₄ 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 C₂H₄, 5.8% O₂ in N₂, 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 C₂H₄ 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.