Abstract :
By using temperature-programmed desorption gas analysis, thermal desorption (TD) of N16O with a small amount of N18O was observed in the temperature range 400–1000 K after N18O adsorption on both CaO and SrO powders at room temperature. TDʹs of N2 and N216O with a small amount of N218O were also observed in the temperature range 400–600 K. Based on IR measurements, NO, (NO)2 and tentative NO2 (or NO3) species were found after N16O adsorption on CaO powders. This suggests that oxygen exchange of N18O with CaO and SrO may occur through NO2− or NO3− type intermediates during migrating on the surfaces involving of a lattice oxygen. N2O desorption may be due to the decomposition of (NO)2, while exchange process is not clear.
