Influence of co-fed gases (O2, CO2, CH4, and H2O) on the N2O decomposition over (Co, Fe)-ZSM-5 and (Co, Fe)-BETA catalysts

Abstract

The influence of co-fed gases (O2, CO2, CH4, and H2O) on the N2O decomposition over (Co or Fe)-BETA and (Co, Fe)-ZSM-5 catalysts prepared by ion exchange method was investigated. Co2+ ions and oxo dinuclear Co species were identified in Co-ZSM-5 and Co-BETA catalysts. Isolated and oligomeric Fe3+ species in cationic sites and Fe2O3 particles were found on surface of the Fe-ZSM-5 and Fe-BETA catalysts. Cobalt catalysts were more actives than iron catalysts for the direct decomposition of N2O. Conversion of N2O over Fe-BETA and Fe-ZSM-5 was remained stable when co-fed O2, CO2, and CH4, but decreases with water vapor. However, Co-BETA and Co-ZSM-5 showed much larger reaction rate for N2O decomposition and were very stable when co-fed O2, CO2, CH4, and especially H2O. The results showed that the higher CH4 consumption during N2O reaction over Co-BETA and Co-ZSM-5 was due to CH4 combustion.