| Abstract
| - Catalytic N2O decomposition has been studied overmetal-substituted hexaaluminates with the general formulaABAl11O19, where A = La, Ba, and B = Mn, Fe, Ni. Thematerials were prepared by coprecipitation via the carbonateroute followed by calcination at 1473 K for 10 h. Inductivelycoupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), transmission electronmicroscopy (TEM), and N2 adsorption techniques wereused to characterize the catalysts. The activity in direct N2Odecomposition was evaluated by means of temperature-programmed reaction and steady-state experiments. Fe- andMn-containing hexaaluminates present the highestactivities. The Ni-containing catalysts are significantlyless active, comparable to the hexaaluminates without metalsubstitution. The catalytic activity was practically notinfluenced by the A cation (La or Ba) in the structure. TheFe- and Mn-substituted hexaaluminates exhibit highactivity and stability for N2O decomposition in mixturessimulating the outlet of the Pt−Rh gauzes in ammonia oxidationreactors, containing N2O, NO, O2, and H2O. These materialsare promising for high-temperature abatement of thispowerful greenhouse gas in the chemical industry, particularlyin nitric acid and caprolactam production.
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