Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5424906 | Surface Science | 2008 | 6 Pages |
Abstract
Fourier transform infra red reflection-absorption spectroscopy (FTIR-RAS), thermal desorption spectroscopy (TDS), and auger electron spectroscopy (AES), were employed to explore the mechanism of NO reduction in the presence of C2H4 on the surface of stepped Pt(3Â 3Â 2). Both NO-Pt and C2H4-Pt interactions are enhanced when NO and C2H4 are co-adsorbed on Pt(3Â 3Â 2). As a result, C2H4 is dissociated at surface temperatures as low as 150Â K, and the N-O stretch band is weakened. The presence of post-exposed C2H4 leads NO desorption from steps to decrease significantly, but the same effect on NO desorption from terraces becomes appreciable only at higher post-exposures of C2H4, e.g., 0.6Â L and 1.2Â L, and proceeds to a much slighter extent. Auger spectra indicate that as a result of the reaction with O from NO dissociation, the amount of surface C species is greatly reduced when NO is post-exposed to a C2H4 adlayer. It is concluded that reduction of NO in the presence of C2H4 proceeds very effectively on the surface of the Pt(3Â 3Â 2), through a mechanism of NO dissociation and subsequent O removal. Following this mechanism, the significant dissociation of adsorbed NO molecules on steps at surface temperatures below 400Â K, and subsequent rapid reaction between the resultant O and C-related species, accounts for the considerable amount of N2 desorption at temperatures below 400Â K.
Related Topics
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Authors
Yuhai Hu, Keith Griffiths,