Catalytic behaviors of chloromethane combustion over the metal-modified ZSM-5 zeolites with diverse SiO2/Al2O3 ratios

• A series of M/ZSM-5 was prepared for the catalytic combustion of chloromethane.
• Co/ZSM-5-30 and Ce/ZSM-5-30 show satisfactory conversions of CH3Cl (87% and 95%).
• Co/, Ce/ZSM-5-30 possess excellent redox abilities and strong acidic properties.

A series of M/ZSM-5 (M = Co, Fe, Ce, and Mn) catalysts with different molar ratios of SiO2/Al2O3 (30, 107) was prepared via a traditional wetness impregnation, and further characterized by XRD, BET, H2-TPR, NH3-TPD, and XPS as well as activity test for the catalytic combustion of chloromethane. Characteristic structure of ZSM-5 is basically maintained even after impregnating the various metallic components. Catalytic activities achieving under an atmosphere of 1500 ppm CH3Cl, 10% O2, and GHSV of 15,000 h−1 of the investigated catalysts follow a trend of Co/ZSM-5-30, Ce/ZSM-5-30 > Co/ZSM-5-107, Ce/ZSM-5-107, Fe/ZSM-5-30, Mn/ZSM-5-30 > Mn/ZSM-5-107, Fe/ZSM-5-107 > H-ZSM-5-30 > H-ZSM-5-107. The binary Co/ZSM-5-30 and Ce/ZSM-5-30 show the satisfactory conversions of CH3Cl (87% and 95%) associated with a low yield of CO (9.6% and 16%) at 400 °C, owing to the excellent redox properties (determined by the chemical nature of the loaded metallic components) and strong acidic properties (modified by Al isomorphic substitution) of the as-prepared zeolitic catalysts.

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