AVS 52nd International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM6
Adsorption of NO2 on Ultrathin @theta@-Al2O3/AlNi(100) Film: the Formation of Nitrite and Nitrate Species

Wednesday, November 2, 2005, 10:00 am, Room 203

Session: Reactions on Metals & Oxides
Presenter: J. Szanyi, Pacific Northwest National Laboratory
Authors: J. Szanyi, Pacific Northwest National Laboratory
E. Ozensoy, Pacific Northwest National Laboratory
C.H.F. Peden, Pacific Northwest National Laboratory
Correspondent: Click to Email
The interaction of NO2 with an ordered @theta@-Al2O3/NiAl(100) model catalyst surface was investigated using temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). The origin of the NOx uptake of the catalytic support (i.e. Al2O3) in a NOx storage catalyst is identified. Adsorbed NO2 is converted to strongly bound nitrites and nitrates that are stable on the model catalyst surface at temperatures as high as 300 and 650 K, respectively. The results show that alumina is not completely inert and may stabilize some form of NOx under certain catalytic conditions. The stability of the NOx formed by exposing the @theta@-Al2O3 model catalyst to NO2 adsorption increases in the order: NO2 (physisorbed or N2O4) < NO2 (chemisorbed) < NO2- < NO3-.