Reaction intermediates in the selective reduction of NO with propene over Ga2O3-Al2O3 and In2O3-Al2O3 catalysts

Minor products formed in the reaction of NO + C3H6 + O-2 over:Ga2O3-Al2O3 and In2O3-Al2O3 were identified by using GC-MS technique. A lot of minor products, such as oxygenated, nitrile, nitrite compounds and higher hydrocarbons were detected on both catalysts. The formation of surface nitrile species in the NO + C3H6 + O-2 reaction was also recognized in the diffuse reflectance FT-IR spectra. FT-IR spectra showed that the reaction starts with the formation of adsorbed nitrate (NO3-) species via NO oxidation by O-2. From the comparison of the distribution of minor products in NO + C3H6 + O-2 and 2-nitropropane oxidation, a reaction pathway in which NO reduction proceeds through the formation of organic nitro compounds and subsequent decomposition to some oxygenated and nitrile compounds was proposed. (C) 2001 Elsevier Science B.V. All rights reserved.