Structural Stability of Metal Containing Ferrierite under the Conditions of HT-N2O Decomposition

Abstract

Ferrierite based catalyst is expected to be used for high-temperature decomposition of N2O. The stability of the ferrierite structure and divalent cations in ferrierite in this process were analysed using XRD, SEM, FTIR, Al-27 and Si-29 MAS NMR. This study provides detailed information regarding to Al removal from zeolite that is either involved in the Bronsted acid sites or formation of local cationic sites responsible for bonding divalent cations. The Al atoms, which stabilize divalent cations in cationic positions, have the potential to be resistant to prolonged exposure to the conditions of high-temperature decomposition of N2O. The presence of water led to the destruction of the iron active sites for N2O decomposition in iron ferrierite. Moreover, the negative role of residual sodium ions eventually remaining in the commercial ferrierite was proven to induce the irreversible collapse of the zeolite framework.