The nature of nitrate species formed in the Al2O3, 8wt%, and 20wt% BaO/Al2O3 catalysts was investigated in a combined TPD, FTIR and 15N solid state NMR study. The results strongly suggest the formation of a monolayer bidentate nitrate on the alumina support that forms upon NO2 exposure. This monolayer nitrate decomposes at lower temperature than bulk Ba(NO3)2 and its only decomposition product is NO2. A bulk-like Ba(NO3)2 phase also forms with its characteristic set of TPD, IR and NMR features. The amount of NOx stored in the monolayer nitrate is proportional to the surface area of the catalyst, while that in the bulk nitrate increases with BaO coverage.
Revised: April 1, 2008 |
Published: January 13, 2005
Citation
Szanyi J., J. Kwak, D. Kim, S.D. Burton, and C.H. Peden. 2005.NO2 Adsorption on BaO/Al2O3: The Nature of Nitrate Species.Journal of Physical Chemistry B 109, no. 1:27-29.PNNL-SA-42873.doi:10.1021/jp045082i