Desikusumastuti A, Schernich S, Happel M, Sobota M, Laurin M, Libuda J (2009)
Publication Status: Published
Publication Type: Journal article
Publication year: 2009
Publisher: WILEY-V C H VERLAG GMBH
Book Volume: 1
Pages Range: 318-325
Journal Issue: 2
The interaction of NO2 with single-crystal-based model NOx storage materials, consisting of barium aluminate nanoparticles on Al2O3/NiAl(110), are investigated by time-resolved infrared reflection absorption spectroscopy (TR-IRAS) at realistic NO2 partial pressures up to 1.75 mbar. The data is compared to spectra obtained under ultrahigh vacuum (UHV) conditions on the same model system. At 300 K, the NO2 uptake at pressures around I mbar proceeds through rapid initial formation of surface nitrites and nitrates, similar to that under UHV conditions. The vibrational spectra of the surface species formed at realistic NO2 pressures are comparable to those for species formed under UHV conditions. Beyond the formation of surface species, the formation of bulk nitrates occurs, but is kinetically strongly hindered. At a very low rate, the formation of a disordered barium bulk nitrate is detected. At 500K, this kinetic hindrance is overcome and the available Ba2+ is quantitatively converted to bulk Ba(NO3)(2). The IRAs spectrum of these Ba(NO3)(2) particles differs characteristically from those obtained for nitrate multilayers formed upon incomplete conversion under UHV conditions. In addition to the formation of bulk Ba(NO3)(2), a more weakly bound disordered nitrate species is formed. This species gives rise to a dynamic NO2 uptake and release well below the decomposition temperature of bulk Ba(NO3)(2). The experiments show that model studies under UHV conditions mainly provide information on the initial reaction mechanism, whereas the observation of actual bulk NOx storage phases requires experiments at realistic temperatures and pressures.
APA:
Desikusumastuti, A., Schernich, S., Happel, M., Sobota, M., Laurin, M., & Libuda, J. (2009). Model NOx Storage Materials at Realistic NO2 Pressures. ChemCatChem, 1(2), 318-325. https://dx.doi.org/10.1002/cctc.200900137
MLA:
Desikusumastuti, Aine, et al. "Model NOx Storage Materials at Realistic NO2 Pressures." ChemCatChem 1.2 (2009): 318-325.
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