Co-ZSM-5 catalysts for N2O decomposition

Abstract

The catalytic properties of cobalt containing ZSM-5 zeolites prepared by various methods were compared. TPR, XRD, N2-BET, XPS, FTIR and UV–vis spectroscopy were used for characterizing the samples. Well-dispersed cobalt oxide-like species and isolated Co2+ ions in charge compensation positions were found in the zeolite. Catalysts prepared using a single step cation exchange method showed high activity for N2O decomposition in a temperature range 300–550°C, in the presence of 0–5% O2, and high stability in the presence of 10% H2O to the feed. UV–vis spectra and TPR experiments indicated the presence of some cobalt oxides, not detected by DRX, in a Co-ZSM-5 catalyst containing 3.76 wt% Co, prepared by a solid-state reaction procedure. The N2O conversion over this catalyst was strongly affected by addition of both O2 and H2O to the feed.