کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5362193 | 1388282 | 2012 | 8 صفحه PDF | دانلود رایگان |
We have studied nitric oxide (NO) adsorption and dissociation on the Nb(1Â 1Â 0) surface by means of density-functional theory and total-energy calculations. The top adsorption sites on the Nb(1Â 1Â 0) surface are found to be energetically the most favorable at the p(1Â ÃÂ 1) surface periodicity, which is in line with experiments investigated by high-resolution electron energy-loss spectroscopy (HREELS). On the Nb(1Â 1Â 0) surface, NO prefers to adsorb in top sites uprightly. With decreasing the coverage NO gradually tilts in hollow sites. At lower coverage (â¼0.25Â ML), the tilted hollow site has been determined to be the preferred adsorption site from total-energy comparison. We have found that NO is easy to dissociate on the Nb(1Â 1Â 0) surface. Four typical dissociation pathways with oxygen atoms of NO dissociated to bridge and top sites are discussed. The further analysis based on electronic states reveal that at 0.25Â ML the essential interaction between a NO monomer and metal substrate is the hybridization of NO 5Ï, 2Ï*-orbital and the d-bands of surface niobium atoms for p(2Â ÃÂ 2) surface.
⺠In the p(1 Ã 1) structure, the theoretical calculation is in good agreement with the available data from HREELS experiments. ⺠On the Nb(1 1 0) surface, NO prefers to adsorb in top sites uprightly. With decreasing the coverage NO gradually tilts in hollow sites. ⺠At lower coverage NO is adsorbed in part dissociatively on hollow sites and in part molecularly on top sites.
Journal: Applied Surface Science - Volume 258, Issue 10, 1 March 2012, Pages 4428-4435