Toluene is a common solvent used in paints, pesticides, resins, etc. Although toluene is found in low concentrations in an indoor environment, long-term exposure to it is hazardous. This research aims to study toluene oxidation in a catalyst-packed dielectric barrier discharge (DBD) reactor designed to withstand high flow rates. The DBD reactor was packed with commercially available Al2O3 first and then with Mn and Co oxide-coated Al2O3. The surface modification of Al2O3 with transition metal oxides significantly improved the reactor's performance. At a power input of 20.3 W (equivalent to 13.0 J/l), MnO2/Al2O3 efficiently decomposed 50 ppm toluene (93%), and the corresponding CO2 selectivity was 57%. The in-situ breakdown of ozone, which leads to the formation of more reactive oxidants such as atomic oxygen, appears to make MnO2/Al2O3 better among the catalysts studied. The mean electron energies and the energy electron distribution function were calculated using the BOLSIG+ program. © 2023 Elsevier B.V.