AVS 50th International Symposium
    Surface Science Thursday Sessions
       Session SS-ThA

Paper SS-ThA9
The Adsorption and Reaction of NO on Single Crystal Titanate (TiO@sub 2@ and SrTiO@sub 3@) Surfaces

Thursday, November 6, 2003, 4:40 pm, Room 328

Session: Oxide Reactions and Catalysis
Presenter: C.H.F. Peden, Pacific Northwest National Laboratory
Authors: C.H.F. Peden, Pacific Northwest National Laboratory
S. Azad, Pacific Northwest National Laboratory
M.H. Engelhard, Pacific Northwest National Laboratory
M.A. Henderson, Pacific Northwest National Laboratory
J. Szanyi, Pacific Northwest National Laboratory
L.-Q. Wang, Pacific Northwest National Laboratory
Correspondent: Click to Email
The control of NOx (NO and NO@sub 2@) emissions from combustion processes, including vehicle engines, remains a challenge particularly for systems operating at high air-to-fuel ratios (so-called 'lean' combustion), where the need is to selectively reduce NOx with a reductant in a large background of the competing oxidizing species, O@sub 2@. A wide variety of oxide materials, including zeolites, are known to be effective for selective catalytic reduction of NOx from the exhaust of 'lean-burn' engines.@footnote 1@ As such, there has been much interest for some time in determining the kinetics of adsorption and surface reactions of NO and NO@sub 2@, as well as identifying the composition and structure of the mechanistically important adsorbed NOx species on this class of catalytic materials. In this presentation, we will discuss selected results from our ongoing studies aimed at addressing some of the considerable remaining uncertainties about these processes.@footnote 2@ In particular, we will compare and contrast the results of our temperature programmed desorption (TPD) and x-ray photoemission spectroscopy (XPS) studies of NO adsorption on single crystal TiO@sub 2@ and SrTiO@sub 3@ surfaces. Both weakly adsorbed NO and the reaction product, N@sub 2@O, were observed in TPD from TiO@sub 2@(110). The N@sub 2@O is formed from an 'NO-like' species identified with XPS. However, NO is the only desorption product from a SrTiO@sub 3@(100) surface. @FootnoteText@ @footnote 1@M. Shelef and R.W. McCabe, Catal. Today 62 (2000) 35. @footnote 2@The work was carried out at Pacific Northwest National Laboratory (PNNL) and funded by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Divisions of Chemical Sciences and Materials Sciences. Experiments were performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility located at PNNL and supported by the DOE's Office of Biological and Environmental Research.