Influence of Si/Al ratio of MFI zeolites on the microstructure and catalytic performance of Co-based catalyst for N2O decomposition
A series of Co-based molecular sieve catalysts with varying Si/Al ratios was synthesized via impregnation. Microstructural properties of Co active sites were characterized by XRD, TEM, Raman, H2-TPR, Py-FTIR, and XPS. Results indicate that surface Co species predominantly exist as CoOx nanoclusters and isolated Co2+, with the latter exhibiting superior N2O decomposition activity. Decreasing the Si/Al ratio of the MFI zeolite promotes the formation of isolated Co2+ active sites, thereby enhancing catalytic performance. Compared to Co/S-1 (pure silica support), the Co/HZ60 catalyst (low Si/Al ratio ZSM-5) lowers the temperature for complete N2O decomposition by 80 °C and demonstrates excellent resistance to O2 and NO. The strong interaction between the zeolite framework and Co2+ inhibits oxidation to Co3+, improving N2O adsorption and activation. This work provides a rational design strategy for efficient and stable Co-based catalysts for N2O abatement in industrial tail gases.