Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface
碩士 === 國立成功大學 === 化學系碩博士班 === 91 === Temperature-programmed reaction/desorption (TPD/R) and reflection absorption infrared spectroscopy (RAIRS) have been employed to investigate the thermal reactions and adsorption geometry of FCH2CH2OH and 1,4-dioxane molecules on clean and oxygen-preadsorbed Cu(10...
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ndltd-TW-091NCKU50650172015-10-13T17:02:34Z http://ndltd.ncl.edu.tw/handle/94020966521810715677 Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface 2-氟乙醇及1,4-dioxane在Cu(100)表面上的熱反應與吸附位向的研究 Pei-Teng Chang 張沛騰 碩士 國立成功大學 化學系碩博士班 91 Temperature-programmed reaction/desorption (TPD/R) and reflection absorption infrared spectroscopy (RAIRS) have been employed to investigate the thermal reactions and adsorption geometry of FCH2CH2OH and 1,4-dioxane molecules on clean and oxygen-preadsorbed Cu(100) surfaces. Molecular desorption predominates in heating FCH2CH2OH adsorbed on clean Cu(100). But ~20% adsorbed FCH2CH2OH molecules at about half monolayer coverage dissociate on the surface to form water, ethylene, and 1,4-dioxane. On the contrary, monolayer FCH2CH2OH completely dissociates on oxidized Cu(100) to form 1,4-dioxane and the surface intermediate of FCH2CH2O(a) which further decomposes to evolve FCH2CHO(g) at temperature higher than ~350 K. The decomposition of FCH2CH2OH to form FCH2CH2O(a) on oxidized Cu(100) begins at ~160 K and is completed prior to 220 K. On clean Cu(100), FCH2CH2OH molecules at ~0.25 monolayer coverage are adsorbed with the C-C-O skeleton approximately parallel to the surface. The C-C-O skeleton tilts away from the surface as the exposure is increased to a half monolayer coverage. However the parallel C-C-O orientation is not observed on the oxidized surface, even at the FCH2CH2OH exposure for a 0.25 monolayer coverage. 1,4-dioxane is adsorbed reversibly on the surface with monolayer desorption at 212 K and multilayer desorption at ∼165 K at 4 L exposure. Below ∼1.5 L exposure, i.e. 0.6 monolayer coverage, 1,4-dioxane molecules are adsorbed with the ring approximately parallel to the surface. C-H…Cu interaction is evidenced by the C-H vibrational mode softening of 2811 cm-1. Increasing 1,4-dioxane exposure leads to tilted geometry for some of the adsorbed molecules: ∼50% at a monolayer coverage at 110 K. However, the monolayer structure is not closely-packed at 110 K, most of the tilted molecules change to flat-lying geometry as the surface temperature is increased to 165 K just prior to the onset of molecular desorption. Jong-Liang Lin 林榮良 2003 學位論文 ; thesis 55 zh-TW |
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碩士 === 國立成功大學 === 化學系碩博士班 === 91 === Temperature-programmed reaction/desorption (TPD/R) and reflection absorption infrared spectroscopy (RAIRS) have been employed to investigate the thermal reactions and adsorption geometry of FCH2CH2OH and 1,4-dioxane molecules on clean and oxygen-preadsorbed Cu(100) surfaces. Molecular desorption predominates in heating FCH2CH2OH adsorbed on clean Cu(100). But ~20% adsorbed FCH2CH2OH molecules at about half monolayer coverage dissociate on the surface to form water, ethylene, and 1,4-dioxane. On the contrary, monolayer FCH2CH2OH completely dissociates on oxidized Cu(100) to form 1,4-dioxane and the surface intermediate of FCH2CH2O(a) which further decomposes to evolve FCH2CHO(g) at temperature higher than ~350 K. The decomposition of FCH2CH2OH to form FCH2CH2O(a) on oxidized Cu(100) begins at ~160 K and is completed prior to 220 K. On clean Cu(100), FCH2CH2OH molecules at ~0.25 monolayer coverage are adsorbed with the C-C-O skeleton approximately parallel to the surface. The C-C-O skeleton tilts away from the surface as the exposure is increased to a half monolayer coverage. However the parallel C-C-O orientation is not observed on the oxidized surface, even at the FCH2CH2OH exposure for a 0.25 monolayer coverage.
1,4-dioxane is adsorbed reversibly on the surface with monolayer desorption at 212 K and multilayer desorption at ∼165 K at 4 L exposure. Below ∼1.5 L exposure, i.e. 0.6 monolayer coverage, 1,4-dioxane molecules are adsorbed with the ring approximately parallel to the surface. C-H…Cu interaction is evidenced by the C-H vibrational mode softening of 2811 cm-1. Increasing 1,4-dioxane exposure leads to tilted geometry for some of the adsorbed molecules: ∼50% at a monolayer coverage at 110 K. However, the monolayer structure is not closely-packed at 110 K, most of the tilted molecules change to flat-lying geometry as the surface temperature is increased to 165 K just prior to the onset of molecular desorption.
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author2 |
Jong-Liang Lin |
author_facet |
Jong-Liang Lin Pei-Teng Chang 張沛騰 |
author |
Pei-Teng Chang 張沛騰 |
spellingShingle |
Pei-Teng Chang 張沛騰 Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
author_sort |
Pei-Teng Chang |
title |
Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
title_short |
Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
title_full |
Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
title_fullStr |
Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
title_full_unstemmed |
Thermal Chemistry and AdsorptionOrientation of 2-Fluoroethanol and 1,4-dioxane on Cu(100) Surface |
title_sort |
thermal chemistry and adsorptionorientation of 2-fluoroethanol and 1,4-dioxane on cu(100) surface |
publishDate |
2003 |
url |
http://ndltd.ncl.edu.tw/handle/94020966521810715677 |
work_keys_str_mv |
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