The deep oxidation of chlorobenzene was investigated over Pt catalysts supported on H-type zeolites (H-ZSM5 and H-beta). Pt/zeolite catalysts showed a higher activity compared to Pt/γ-Al2O3 samples which were tested for comparison. Within each class of zeolite, the activity of Pt/zeolite catalysts was found to be higher on the samples with lower SiO2/Al2O3 ratio. Amounts of polychlorinated benzenes (PhClx) were produced in the order Pt/H-ZSM5