Superior performance in catalytic combustion of toluene over mesoporous ZSM-5 zeolite supported platinum catalyst

Abstract

Catalytic combustion over zeolite supported platinum catalysts is regarded as one of the efficient methods for removal of volatile organic compounds (VOCs). In this work, we show a preparation of Pt loaded mesoporous ZSM-5 zeolite (Pt/Meso-ZSM-5) with various cations. The sample N2 sorption isotherms and TEM image show abundant mesoporosity existing in the zeolite crystals. The catalytic toluene combustion tests show that the Pt/Meso-ZSM-5 catalysts have higher activities than conventional ZSM-5 supported Pt catalysts (Pt/ZSM-5), which is related to their difference in the concentration of active sites Pt0 and the rate of mass transfer. Particularly, after reduction with hydrogen at 300°C, the Pt nanoparticles supported on Meso-ZSM-5 with K+ and Cs+ cations (Pt-R/Meso-KZSM-5 and Pt-R/Meso-CsZSM-5) exhibit much higher activities than those on Meso-ZSM-5 with Na+ and H+ cations, which is well consistent with their order of the Pt0 concentration. For example, Pt-R/Meso-KZSM-5 gives the temperature for conversion of 98% toluene (T98) at only 175°C, while Pt-R/Meso-HZSM-5 shows the T98 at 190°C. More importantly, Pt-R/Meso-KZSM-5 has a long life, and its activity cannot be influenced by the water and CO2. These features are critically important for practical applications of these catalysts in the future.