Revealing the effect of framework acidity on the catalytic combustion of vinyl chloride over zeolite-based catalysts

The study explored the effect of different types of acid sites on the catalytic combustion of vinyl chloride over zeolite-based catalysts. MFI-type zeolites were synthesized using impregnation method and loaded with the noble metal Ru. Results indicated that the Ru/Sn-MFI catalysts possessed only Lewis acid sites, the Ru/Al-MFI catalysts were primarily governed by Bronsted acid sites, and the Ru/Si-MFI catalysts had no acid sites. The Ru/Sn-MFI catalyst containing Lewis acid sites demonstrated increased catalytic activity, with a T90 of up to 306 C-degrees, and efficiently prevented the formation of chlorinated by-products. In contrast, the Ru-Si/MFI catalyst exhibited inferior catalytic activity. While a significant amount of chlorinated by-products was generated on the Ru/Al-MFI catalyst. The substantial amount of Lewis acid sites on the surface of Ru/Sn-MFI catalyst facilitated the activation of C-Cl bonds and the cleavage of C-C bonds. Furthermore, the Ru/Sn-MFI catalysts had improved lowtemperature reducibility and oxygen mobility, which contributed to the deep oxidation of vinyl chloride.