Catalytic Oxidation of Chlorobenzene over MnxCe1-xO2/HZSM-5 Catalysts: A Study with Practical Implications

Industrial-use catalysts usually encounter severe deactivation after long-term operation for catalytic oxidation of chlorinate volatile organic compounds (CVOCs), which becomes a "bottleneck" for large-scale application of catalytic combustion technology. In this work, typical acidic solid-supported catalysts of MnxCe1-xO2/HZSM-5 were investigated for the catalytic oxidation of chlorobenzene (CB). The activation energy (Ea), Bronsted and Lewis acidities, CB adsorption and activation behaviors, long-term stabilities; and surficial accumulation compounds (after aging) were studied using a range of analytical techniques; including XPS, H-2-TPR, pyridine-IR, DRIFT, and O-2-TP-Ms. Experimental results :revealed that the Bronsted/Lewis (B/L) ratio of MnxCe1-xO2/HZSM-5 catalysts could be adjusted by ion exchange of H center dot (in HZSM-5) with Mn+ (where the exchange with Ce4+ did not distinctly affect the acidity); the long-term aged catalysts could accumulate ca. 14 organic compounds at surface, including highly toxic tetrachloromethane, trichloroethylene, tetrachloroethylene, o-dichlorobenzene, etc; high humid operational environment could ensure a stable performance for MnxCe1-x/HZSM-5 catalysts; this was due to the effective removal of Cl center dot and coke accumulations by H2O washing, and the distinct increase of Lewis acidity by the interaction of H2O with HZSM-5. This work gives an in-depth view into the CB oxidation over acidic solid-supported catalysts and could provide practical guidelines for the rational design of reliable catalysts for industrial applications.