کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5424577 | 1395829 | 2009 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Adsorption of CO, CO2 and NO molecules on a BaTiO3 (0Â 0Â 1) surface
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Since the development of Scanning Tunnelling Microscopy (STM) technique, considerable attention has been devoted to various molecules adsorbed on various surfaces. Also, a new concept emerged with molecules on surfaces considered as nano machines by themselves. In this context, a thorough knowledge of surfaces and adsorbed molecules at an atomic scale are thus particularly invaluable. The present work describes the first Density Functional Theory (DFT) study of adsorption of CO, CO2 and NO molecules on a BaTiO3 surface following a first preliminary calculation of O and O2 adsorption on the same surface. In the previously considered work, we found that a (0Â 0Â 1) surface with BaO termination is more stable than the one with TiO2-termination. Consequently, we extended our study to CO, CO2 and NO molecules adsorbed on a (0Â 0Â 1) surface with BaO termination. The present calculation was performed on a (1Â ÃÂ 1) cell with one monolayer of adsorbed molecules. Especially, a series of cases implying CO molecules adsorbed in various geometrical configurations has been examined. The corresponding adsorption energy varies in the range of â0.17 to â0.10Â eV. The adsorption energy of a CO2 molecule directly located above an O surface atom (called Os) is of the order of â0.18Â eV. The O-C distance length is then 1.24Â Ã
and the O-C-O and O-C-Os angles are 134.0° and 113.0°, respectively. For NO adsorption, the most important induced structural changes are the followings: (i) the N-O bond is broken when a NO molecule is absorbed on a Ba-Os bridge site. In that case, N and O atoms are located above an O and a Ba surface atom, respectively, whereas the O-Ba-Os and N-Os-Ba angles are 106.5° and 63.0°, respectively. The N-O distance is as large as 2.58 Ã
and the adsorption energy is as much as â2.28 eV. (ii) In the second stable position, the NO molecule has its N atom adsorbed above an Os atom, the N-O axis being tilted toward the Ba atom. The N-Os-Ba angle is then 41.1° while the adsorption energy is only â0.10 eV. At last, the local densities of states around C, O as well as N atoms of the considered adsorbed molecules have also been discussed.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Surface Science - Volume 603, Issue 9, 1 May 2009, Pages 1221-1228
Journal: Surface Science - Volume 603, Issue 9, 1 May 2009, Pages 1221-1228
نویسندگان
G. Rakotovelo, P.S. Moussounda, M.F. Haroun, P. Légaré, A. Rakotomahevitra, M. Rakotomalala, J.C. Parlebas,