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Ma Z. Solvent effect on CO oxidation as a novel diagnosing tool to pin down low-coverage CO at the liquid–solid interface: An in situ infrared study. J Colloid Interface Sci 2006; 304:419-30. [PMID: 17028007 DOI: 10.1016/j.jcis.2006.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2006] [Revised: 08/30/2006] [Accepted: 09/04/2006] [Indexed: 10/24/2022]
Abstract
In situ probing of liquid-solid interfaces is important for understanding heterogeneous liquid-phase catalysis and other interfacial phenomena, but the spectroscopic interference from the bulk is often a problem. Some organics may have infrared features overlapping the adsorbed CO peaks, making the determination of adsorbed CO difficult. In this study, CCl4-flushing was used as a novel diagnosing tool to pin down the low-coverage CO derived from decarbonylation of organics. This diagnosing tool was designed based on our in situ reflection-absorption infrared spectroscopy results reported here that there is a marked solvent effect (water > ethanol > methanol > cyclohexane > benzene approximately carbon tetrachloride) on CO oxidation at the liquid-solid interface. Possible reasons for that solvent effect were discussed.
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Affiliation(s)
- Zhen Ma
- Department of Chemistry, University of California, Riverside, CA 92521, USA.
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Jäggle C, Swiderek P, Breton SP, Michaud M, Sanche L. Products and Reaction Sequences in Tetrahydrofuran Exposed to Low-Energy Electrons. J Phys Chem B 2006; 110:12512-22. [PMID: 16800580 DOI: 10.1021/jp0614291] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Electron-stimulated reactions in solid films of tetrahydrofuran (THF), condensed on Kr spacers deposited on a Pt substrate, or directly onto the substrate, were induced and monitored simultaneously with use of high-resolution electron-energy-loss spectroscopy in the ranges of vibrational and electronic excitations. The spectra of the molecular films obtained after a certain time of exposure to electrons at incident energies of 14 and 15.5 eV were analyzed and different products were identified. Besides an aldehyde, which is the main product, olefins, conjugated olefins, as well as CO were identified. Closer investigation of the reactions of propionaldehyde, as a model aldehyde, demonstrates that CO appears in THF as a secondary product (i.e., from the intermediate aldehyde). On the basis of the cross sections for the formation of an aldehyde from THF, of CO from propionaldehyde, and for the loss of propionaldehyde under electron impact, the reaction sequences were evaluated with the help of a kinetic model. This analysis suggests that some CO could also be formed directly from THF (i.e., without involvement of an intermediate aldehyde).
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Affiliation(s)
- Claudia Jäggle
- Universität Bremen, Fachbereich 2 (Chemie/Biologie), Leobener Strasse/NW 2, Postfach 330440, 28334 Bremen, Germany
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Huang HG, Huang JY, Cai YH, Xu GQ. Vibrational studies of the reactions of acetophenone with Si(100)–2×1. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.07.110] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Huang HG, Zhang YP, Cai YH, Huang JY, Yong KS, Xu GQ. Selective attachment of benzaldehyde on Si(100)-2×1: Structure, selectivity, and mechanism. J Chem Phys 2005; 123:104702. [PMID: 16178613 DOI: 10.1063/1.2035095] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interaction of benzaldehyde with the Si(100) surface has been investigated as a model system for understanding the interaction of conjugated pi-electron systems with semiconductor surfaces. Vibrational features of chemisorbed benzaldehyde unambiguously demonstrate that the carbonyl group directly interacts with the Si surface dangling bonds, evidenced in the disappearance of the C=O stretching mode around 1713 cm(-1) coupled with the retention of all vibrational signatures of its phenyl ring. X-ray photoemission spectroscopy shows that both C 1s and O 1s binding energies of the carbonyl group display large downshifts by 1.9 and 1.3 eV, respectively. Vibrational and electronic results show that the covalent attachment of benzaldehyde on Si(100) occurs in a highly selective manner through the direct interaction of both C and O atoms of the carbonyl group with a Si=Si dimer to form a four-membered Si-C-O-Si ring at the interface, leaving a nearly unperturbed phenyl ring protruding into vacuum. This conclusion is further confirmed by the observation of a predominant protrusion for benzaldehyde adsorbed on Si(100)-2 x 1 in scanning tunneling microscopy experiments, consistent with the predication of density-functional theory calculation.
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Affiliation(s)
- Hai Gou Huang
- Department of Chemistry, National University of Singapore
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Huang HG, Cai YH, Huang JY, Tang HH, Xu GQ. Formation of a tetra-sigma-bonded intermediate in acetylethyne binding on Si(100)-2 x 1. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:3384-3388. [PMID: 15807577 DOI: 10.1021/la047107a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The covalent binding of acetylethyne on Si(100)-2 x 1 has been investigated using high-resolution electron energy loss spectroscopy (HREELS) and X-ray photoelectron spectroscopy (XPS). The HREELS spectra of chemisorbed monolayers show the absence of the C=O, C[triple bond]C, and C(sp)-H stretching modes coupled with the appearance of C=C (at 1580 cm(-1)) and C(sp2)-H (at 3067 cm(-1)) stretching modes. This demonstrates that both of the C=O and CC groups of acetylethyne directly participate in binding with silicon surfaces to form C-O and C=C bonds, respectively, which is further confirmed by the XPS studies. A tetra-sigma-binding configuration through two [2 + 2]-like cycloaddition reactions in acetylethyne binding on Si(100) is proposed to account for the experimental observation. The cycloadduct containing a C=C double bond may be employed as an intermediate for further in situ chemical syntheses of multilayer organic thin films or surface functionalization.
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Affiliation(s)
- Hai Gou Huang
- Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore 119260
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Swiderek P, Deschamps MC, Michaud M, Sanche L. Absolute Cross Sections for the Electron-Induced Formation of Unsaturated Hydrocarbons from Solid Cyclopropane. J Phys Chem B 2004. [DOI: 10.1021/jp048591t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Petra Swiderek
- Universität Bremen, Fachbereich 2 (Chemie/Biologie), Leobener Strasse/NW 2, Postfach 330440, 28334 Bremen, Germany
| | - Mathieu C. Deschamps
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
| | - Marc Michaud
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
| | - Léon Sanche
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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7
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White J. Using photons and electrons to drive surface chemical reactions1Dedicated to the memory of Brian Bent whose work stimulated much of our own and whose pleasant encouragement never failed.1. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1381-1169(97)00257-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Schwaner AL, White JM. Methyl Formate on Ag(111). 2. Electron-Induced Surface Reactions. J Phys Chem B 1997. [DOI: 10.1021/jp9716501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. L. Schwaner
- Center for Materials Chemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
| | - J. M. White
- Center for Materials Chemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
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Affiliation(s)
- A. L. Schwaner
- Center for Materials Chemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
| | - J. M. White
- Center for Materials Chemistry, Department of Chemistry and Biochemistry, University of Texas, Austin, Texas 78712
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Sparks SC, Szabo A, Szulczewski GJ, Junker K, White JM. Thermal, Electron, and Photon Induced Chemistry of Acetone on Ag(111). J Phys Chem B 1997. [DOI: 10.1021/jp972005x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stacy Converse Sparks
- Department of Chemistry and Biochemistry, Center For Materials Chemistry, University of Texas, Austin, Texas 78712
| | - Andras Szabo
- Department of Chemistry and Biochemistry, Center For Materials Chemistry, University of Texas, Austin, Texas 78712
| | - G. J. Szulczewski
- Department of Chemistry and Biochemistry, Center For Materials Chemistry, University of Texas, Austin, Texas 78712
| | - K. Junker
- Department of Chemistry and Biochemistry, Center For Materials Chemistry, University of Texas, Austin, Texas 78712
| | - J. M. White
- Department of Chemistry and Biochemistry, Center For Materials Chemistry, University of Texas, Austin, Texas 78712
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Pylant ED, Junker KH, Szulczewski G, Hubbard MJ, White JM. Photon-Driven Chemistry of Biacetyl on Ag(111). J Phys Chem B 1997. [DOI: 10.1021/jp9700387] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- E. D. Pylant
- Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas, Austin, Texas 78712
| | - K. H. Junker
- Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas, Austin, Texas 78712
| | - G. Szulczewski
- Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas, Austin, Texas 78712
| | - M. J. Hubbard
- Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas, Austin, Texas 78712
| | - J. M. White
- Department of Chemistry and Biochemistry, Center for Materials Chemistry, University of Texas, Austin, Texas 78712
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