Influence of extra-framework Al in Fe-MOR catalysts for the direct conversion of methane to oxygenates by nitrous oxide

Iron-containing zeolites play an important role in the selective oxidation of methane to oxygenates by nitrous oxide. A solid-state ion exchange method is adopted to prepare Fe-MOR zeolite catalysts with different amounts of extra-framework Al. EPR spectra and UV-vis spectra show that the percentage of iron ions in tetrahedral or octahedral coordination increases while those of dustered Fe species decrease by the addition of extra-framework Al species. Nitrous oxide titration reveals that more active Fe centers are formed, which promote the nitrous oxide consumption. The number of active centers in the catalyst with the introduction of extra-framework Al is about four times that of the catalyst without the addition of extra-framework AI. Due to this, there is an increase in the methane conversion, total selectivity and yield of oxygenates. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved

Automated summary

Iron-containing zeolites play an important role in the selective oxidation of methane to oxygenates by nitrous oxide. A solid-state ion exchange method is adopted to prepare Fe-MOR zeolite catalysts with different amounts of extra-framework Al. The addition of extra-framework Al species increases the percentage of iron ions in tetrahedral or octahedral coordination, leading to more active Fe centers and higher methane conversion rates.