Decomposition of N20 over hexaaluminate catalysts.
Catalytic N2O decomposition has been studied over metal-substituted hexaaluminates with the general formula ABAl11O19, where A = La, Ba, and B = Mn, Fe, Ni. The materials were prepared by coprecipitation via the carbonate route followed by calcination at 1473 K for 10 h. Inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorption techniques were used to characterize the catalysts. The activity in direct N20 decomposition was evaluated by means of temperature-programmed reaction and steady-state experiments. Fe- and Mn-containing hexaaluminates present the highest activities. The Ni-containing catalysts are significantly less active, comparable to the hexaaluminates without metal substitution. The catalytic activity was practically not influenced by the A cation (La or Ba) in the structure. The Fe- and Mn-substituted hexaaluminates exhibit high activity and stability for N2O decomposition in mixtures simulating the outlet of the Pt-Rh gauzes in ammonia oxidation reactors, containing N2O, NO, O2, and H2O. These materials are promising for high-temperature abatement of this powerful greenhouse gas in the chemical industry, particularly in nitric acid and caprolactam production.
Santiago
Marta
M
Laboratory for Heterogeneous Catalysis, Institute of Chemical Research of Catalonia, Av. Pairsos Catalans 16, 43007, Tarragona, Spain.
Pérez-Ramírez
Javier
J
D000535:Aluminum / Q000737:chemistry*; D002384:Catalysis; D046529:Microscopy, Electron, Transmission; D014961:X-Ray Diffraction
D000535:Aluminum