Enhanced catalytic activity and stability of Ce doping on Cr supported HZSM-5 catalysts for deep oxidation of chlorinated volatile organic compounds

• Catalysts containing acidity and oxidizability are prepared by impregnation method.
• Formation of Ce–Cr mixed oxides is beneficial to stabilizing active components.
• Carbon deposition and chlorine adsorption are the main factors for deactivation.
• 9%Cr–12%CeO2/HZSM-5 shows preferable activity and stability for destruction of CVOCs.

The CeO2 or/and Cr2O3 modified HZSM-5 zeolite (molar ratio SiO2/Al2O3 = 22) catalysts were prepared by impregnation method and investigated in the catalytic behavior for decomposition of 1,2-dichloroethane (DCE), dichloromethane (DCM) and trichloroethylene (TCE), as well as the durability during 100 h exposure to DCE. The results indicate that 9%Cr–12%CeO2/HZSM-5 exhibits the best catalytic activity and durability for the degradation of CVOCs. The interaction between CeO2 and Cr2O3 increases the amount of Cr6+ species with stronger oxidation ability and promotes the mobility of active oxygen species in the modified HZSM-5 catalyst, which is benefit for the deeper oxidation of the intermediates produced in the destruction process of CVOCs and improves the resistance to coke deposit. While the synergy between CeO2 or/and Cr2O3 and HZSM-5 zeolite can promote the dehydrochlorination of CVOCs as well as the formation of suitable strength and density ratio of strong and weak acidity, which is also in favor of improving the ability for the catalytic degradation of CVOCs.