کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5356250 | 1388202 | 2015 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Adsorption of O2 and C2Hn (n = 2, 4, 6) on the Al9Co2(0 0 1) and o-Al13Co4(1 0 0) complex metallic alloy surfaces
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موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Oxidation of the Al9Co2(0Â 0Â 1) and Al13Co4(1Â 0Â 0) surfaces has been performed in a wide range of temperatures at 2Â ÃÂ 10â8 or 1Â ÃÂ 10â7Â mbar oxygen pressure. Only AlO bonding is observed. The oxidation kinetics are controlled by the quantity of oxygen sticking on the surface. Oxidation results from a competition between several effects: formation of an oxide film, dissolution of the film, oxygen desorption and oxygen dissolution into the bulk. For temperatures lower than 710Â K for the Al9Co2(0Â 0Â 1) surface and 925Â K for the Al13Co4(1Â 0Â 0) surface, a â¼5Â Ã
thick oxide film is formed which does not show any long-range order and desorbs upon annealing. When oxidation is performed at higher temperatures, oxygen diffusion into the bulk is observed. A poorly ordered oxide film having a sixton structure is formed on the Al9Co2(0 0 1) surface when oxidation is performed at 775 K, which is dissolved when annealing at higher temperatures. On the Al13Co4(1 0 0) surface, only a weak streaky polar circle is observed following annealing at 925 K the film formed at room temperature, which corresponds to an hexagonal network of O atoms into small ultrathin oxide layers domains. The oxidation behaviour of the Al9Co2(0 0 1) and Al13Co4(1 0 0) surfaces has been ascribed to the strong covalent character of bonds present in these AlCo phases, which prevents aluminium diffusion. C2Hn molecules (n = 2, 4, 6) do not adsorb on the Al13Co4(1 0 0) surface in the experimental conditions used in this study, thus suggesting that this surface might not be the active one in the semi-hydrogenation of acetylene.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Surface Science - Volume 357, Part B, 1 December 2015, Pages 1666-1675
Journal: Applied Surface Science - Volume 357, Part B, 1 December 2015, Pages 1666-1675
نویسندگان
M. Wardé, M. Herinx, J. Ledieu, L.N. Serkovic Loli, V. Fournée, P. Gille, S. Le Moal, M.-G. Barthés-Labrousse,