Rational Design of a Novel Core–Shell Cu-ZSM-5@Ru/S-1 Tandem Catalyst for the Catalytic Combustion of Dichloromethane

Abstract

To achieve a well synergistic effect between dissociative adsorption and deep oxidation during the dichloromethane (DCM) catalytic combustion process, a novel tandem catalyst, Cu-ZSM-5@Ru/S-1, was developed by rationally designing the catalyst structure. Activity experiments revealed that the Cu-ZSM-5@Ru/S-1 catalyst achieved a DCM conversion and mineralization rate of over 90% under a 5% H2O atmosphere at 290 °C with a low Ru loading of 0.2 wt %. The mineralization rate of the Cu-ZSM-5@Ru/S-1 was approximately 78% higher than that of the Cu-ZSM-5 catalyst, and the activity was approximately 55% higher than that of the Ru/HZSM-5 catalyst. Furthermore, the in situ characterizations and simulation results indicated that the DCM catalytic reaction followed a tandem reaction mechanism. The initial dissociative adsorption and conversion of DCM primarily occurred in internal Cu-ZSM-5 active sites, and the deep oxidation of the intermediates was subsequently achieved on the Ru/S-1 shell. The two steps mentioned above acted synergistically to enhance both DCM dechlorination and deep oxidation. In addition, the PCDD/F emission of Cu-ZSM-5@Ru/S-1 catalyst at 350 and 400 °C met the national standard for municipal solid waste incineration (0.1 ng I-TEQ Nm–3). Overall, this study provides new strategies for developing highly active and cost-effective catalysts for CVOC catalytic combustion.