Developments on advanced catalysts for catalytic oxidation of chlorinated hydrocarbons still encounter bottlenecks in Cl-center dot deactivation, low HCI and CO2 selectivity, toxic by-products generation, etc. In this paper, a well-reported MnxCe1-xO2 catalyst was selected as active phase to access the role of H-ZSM5 in catalytic oxidation of chlorobenzene (CB) under both dry and humid conditions. The HCI and CO2 production, by-products generation and CB oxidation routes variation were evaluated by using a range of analytical techniques including XRD, BET, GC/MS, in situ DRIFT, Ion Chromatography, etc. It was noted that the presence of H-ZSM5 could induce ca. 90% CB conversion at ca. 230 degrees C. However, only 20% CB was converted into CO2. There were nearly 25 by-products being detected in the off-gas. In situ DRIFT analyses revealed that under dry condition, the H-ZSM5 could promote Cl-center dot dissociation from the aromatic ring of CB, which transferred the CB into cyclohexanone or benzoquinone species, hence facilitating CB ring-opening process. Under humid condition, the presence of H2O could not only protect the active sites of Mn0.8Ce0.2P2 from accumulated chlorine poisoning but also act as H-center dot and OH center dot radical source to deeply oxidize CB, promoting the HCI and CO2 production over the MnxCe1-xO2/H-ZSM5 catalyst. (C) 2016 Elsevier B.V. All rights reserved.