کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9607859 | 46064 | 2005 | 18 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
The effect of calcination temperature on the adsorption of nitric oxide on Au-TiO2: Drifts studies
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
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![عکس صفحه اول مقاله: The effect of calcination temperature on the adsorption of nitric oxide on Au-TiO2: Drifts studies The effect of calcination temperature on the adsorption of nitric oxide on Au-TiO2: Drifts studies](/preview/png/9607859.png)
چکیده انگلیسی
The nitrate surface species, which dominate the spectra after extended exposure, are virtually the same and behave in the same way under in situ thermal desorption experiments. However, nitrate formation on Au-TiO2 is relatively fast compared with the situation found for TiO2. Mechanisms for the formation of these species are discussed and compared with previously reported data. For Au-TiO2, two characteristic bands at 1685 and 1644Â cmâ1 for Dry-Au-T and at 1682 and 1643Â cmâ1 for Au-T973 were detected at room temperature and dominated the initial spectra. The sites containing these NO molecules were populated first. For Dry-Au-T, the higher wavenumber mode (1685Â cmâ1), assigned to bridging NO adsorbate, decreased in intensity during NO adsorption to produce a very weak feature and is assumed to contribute to the dissociation of NO on this catalyst. However, the lower wavenumber mode (1644Â cmâ1), assigned to NO adsorbed at the gold-oxide interface, shifts to lower wavenumber and acts as a precursor state for the activated NO states detected at 1750 and 1714Â cmâ1 on raising the temperature to 473Â K. In contrast, for Au-T973, the lower wavenumber mode (1643Â cmâ1) is associated with a unit which undergoes dissociation, while the high wavenumber mode (1682Â cmâ1) is assigned to a precursor state for the thermally activated NO states detected at 1744 and 1714Â cmâ1 at 473Â K. This trend is explained in terms of the changes in the degree of interaction between gold and the underlying TiO2 support brought about upon calcination. The results are discussed and correlated with previous observations on gold catalysts in an attempt to assess the impact of these thermally activated NO states on the decomposition and selective catalytic reduction of NO over gold catalysts.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 291, Issues 1â2, 12 September 2005, Pages 98-115
Journal: Applied Catalysis A: General - Volume 291, Issues 1â2, 12 September 2005, Pages 98-115
نویسندگان
M.A. Debeila, N.J. Coville, M.S. Scurrell, G.R. Hearne,