Decomposition of nitrous oxide on pillared clays

Alumina-pillared smectites have been found to abate nitrous oxide in the pr esence of methane. The results indicate that the yield of the reaction (N2O --> N-2 + (1/2)O-2) increases when pillared claps are exchanged with trans ition metals, single-pass conversion rates of >70% being attainable. In par ticular, when double exchanged (calcium and subsequently copper) alumina pi llared montmorillonite/beidellite is used as a catalyst, de-N2O activity re aches a maximum, which is maintained even after 4 h of work at a space velo city of 5.5 h(-1). A mechanism for the reaction is suggested, which implies that N2O is first adsorbed by the catalyst and then decomposes through two different paths: catalyst oxidation and catalyst reduction. Such a redox p rocess explains the kinetic data. (C) 2000 Elsevier Science Ltd. All rights reserved.