AVS 54th International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP30
Strong Interaction between BaO and Al2O3 in NOx Storage Materials: Correlation between Model and High Surface Area Catalysts

Tuesday, October 16, 2007, 6:00 pm, Room 4C

Session: Surface Science Poster Session
Presenter: C.-W. Yi, Pacific Northwest National Laboratory
Authors: C.-W. Yi, Pacific Northwest National Laboratory
J.H. Kwak, Pacific Northwest National Laboratory
C.H.F. Peden, Pacific Northwest National Laboratory
C.M. Wang, Pacific Northwest National Laboratory
J. Szanyi, Pacific Northwest National Laboratory
Correspondent: Click to Email

A series of Ba-containing NOx storage reduction (NSR) model catalysts were prepared by reactive layer-assisted deposition (RLAD) of Ba onto Al2O3/NiAl(110) and investigated with surface science techniques. Upon NO2 exposure the model catalysts demonstrated corresponding properties to the high surface area ones. Initially nitrite species form, and then Ba ions are pulled out from the surface at higher NO2 exposures, resulting in the formation of ionic barium nitrates. The formation and agglomeration of Ba(NO3)2 clusters were observed by infrared reflection absorption (IRA) and x-ray photoelectron spectroscopies (XPS) for the model systems, and by Fourier transform infrared (FT-IR), time-resolved synchrotron x-ray diffraction (TR-XRD), and high resolution scanning transmission electron microscopy (HR-STEM) for the high surface area catalysts. The correlation between the model and real catalysts shown here for NO2 adsorption and reaction strongly emphasizes the value of well-designed surface science studies aimed at understanding practical catalytic systems, and this approach ultimately can allow us to develop NSR catalysts with better performances.