A catalytic and in situ Raman spectroscopy study of the decomposition of nitrous oxide over barium oxide supported on magnesium oxide Original Research Article

The decomposition of N2O in a 10% N2O/He mixture occurs at a rate of 0.8 μmol g−1 s−1 at 500°C over a catalyst containing 14 mol% BaO on MgO (Ba/MgO). Barium oxide is the active component. The reaction is inhibited by O2, via the formation of surface barium peroxide ions. The decrease in activity due to inhibition of O2 and the increase in both surface and crystalline BaO2 were followed in several transient experiments. The variation in peroxide concentrations was determined under catalytic conditions using Raman spectroscopy. The transient results are consistent with a mechanism in which N2O reacts with surface oxide ions to form peroxide ions. At steady state, the surface peroxide ions are nearly in equilibrium with gas phase O2. The equilibrium favors extensive decomposition of the peroxide ions to O2 and surface oxide ions under the conditions of the catalytic reaction.