Laboratory-scale experiments were performed to evaluate the efficiency of toluene decomposition by using a wire-plate dielectric barrier discharge (DBD) reactor with manganese oxide/alumina/nickel foam catalyst in the discharge area at room temperature and atmospheric pressure. The effects of oxygen content and gas flow rate were investigated. Under the optimal oxygen content and gas flow rate conditions, the combination effect of DBD and catalyst was observed, and the catalyst before/after discharge was structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform-infrared spectroscopy (FT-IR). It has been found that combining DBD with catalyst in situ could improve the toluene removal efficiency, increase carbon dioxide selectivity and suppress byproducts formation. Whether the catalyst existed or not, the major products were carbon dioxide and carbon monoxide when oxygen was enough. The characterization of the catalyst suggested that DBD enhanced the dispersion of the active species, increased the stability as well as the activity of the catalyst, and strengthened the oxidation capability of the catalyst, therefore the removal of toluene was promoted. (c) 2005 Elsevier B.V. All rights reserved.