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.