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Liao GJ, Hsueh WH, Yen YH, Shih YC, Wang CH, Wang JH, Luo MF. Decomposition of methanol-d4 on a thin film of Al2O3/NiAl(100) under near-ambient-pressure conditions. J Chem Phys 2023; 158:2887766. [PMID: 37129140 DOI: 10.1063/5.0151135] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
We have studied the decomposition of methanol-d4 on thin film Al2O3/NiAl(100) under near-ambient-pressure conditions, with varied surface-probe techniques and calculations based on density-functional theory. Methanol-d4 neither adsorbed nor reacted on Al2O3/NiAl(100) at 400 K under ultrahigh vacuum conditions, whereas they dehydrogenated, largely to methoxy-d3 (CD3O*, * denoting adsorbates) and formaldehyde-d2 (CD2O*), on the surface when the methanol-d4 partial pressure was increased to 10-3 mbar and above. The dehydrogenation was facilitated by hydroxyl (OH* or OD*) from the dissociation of little co-adsorbed water; a small fraction of CD2O* interacted further with OH* (OD*) to form, via intermediate CD2OOH* (CD2OOD*), formic acid (DCOOH* or DCOOD*). A few surface carbonates were also yielded, likely on the defect sites of Al2O3/NiAl(100). The results suggest that alumina not only supports metal clusters but also participates in reactions under realistic catalytic conditions. One may consider accordingly the multiple functions of alumina while designing ideal catalysts.
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Affiliation(s)
- Guan-Jr Liao
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Wen-Hao Hsueh
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei, Taiwan
| | - Yu-Hsiang Yen
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Yi-Chan Shih
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Chia-Hsin Wang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Jeng-Han Wang
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei, Taiwan
| | - Meng-Fan Luo
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
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2
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Gura L, Soares EA, Paier J, Stavale F, Freund HJ. Models for Reactions in Confined Space: Can Surface Science Contribute? A Review and Perspective. Top Catal 2023. [DOI: 10.1007/s11244-023-01787-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AbstractThis paper reports and discusses some of our recent advances in surface science research on a silica film supported on a Ru(0001) substrate. This system is unique, as the silica is bound to the metal surface by dispersive forces only, and thus opens the possibility to study reactions in the confined space between the metal substrate and the silica film, acting as a permeable membrane. We demonstrate that this system allows for detailed insights into the complexity of reactions in confined space, including phenomena due to the response of the confined space to the presence of the reactants, and direct comparison to the situation when the same reaction occurs in open space.
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3
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Investigation of Thermal Stability and Reactivity of Rh Nanoclusters on an Ultrathin Alumina Film. Catalysts 2019. [DOI: 10.3390/catal9110971] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We studied the structural and morphological evolution of Rh clusters on an ordered ultrathin alumina film grown on NiAl(100) in annealing processes, under ultrahigh vacuum conditions and with various surface probe techniques. The Rh clusters, prepared on vapor deposition of Rh onto the alumina film at 300 K, had an fcc phase and grew in the (100) orientation; the annealing altered the cluster structure little—the lattice parameter decreased by a factor <2%—but the cluster morphology significantly. With elevated temperature, small clusters (diameter ≤1.5 nm) decreased little in size; in contrast, large clusters (diameter ≥2.0 nm) varied in a complex manner—their mean diameter decreased to about 1.5 nm on annealing to 450 K, despite their similar height, while it increased to above 2.0 nm at temperature ≥570 K. This atypical decrease in size was governed predominantly by energetics. Such a reduced size enhanced the total surface area as well as the reactivity of the clusters toward methanol decomposition, so increased the production of D2 (H2) and CO from decomposed methanol-d4 (or methanol). The result implies a higher temperature tolerance for Rh clusters on the alumina film and a practical approach to prepare small Rh clusters with high reactivity.
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4
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Meyer T, Nilius N. Tungsten deposits facilitate oxidation of the NiAl(110) surface. J Chem Phys 2019; 150:124701. [DOI: 10.1063/1.5091102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas Meyer
- Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg, Germany
| | - Niklas Nilius
- Institut für Physik, Carl von Ossietzky Universität, D-26111 Oldenburg, Germany
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5
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Zabka WD, Mosberger M, Novotny Z, Leuenberger D, Mette G, Kälin T, Probst B, Osterwalder J. Functionalization and passivation of ultrathin alumina films of defined sub-nanometer thickness with self-assembled monolayers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:424002. [PMID: 30160653 DOI: 10.1088/1361-648x/aaddd3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Instability of ultrathin surface oxides on alloys under environmental conditions can limit the opportunities for applications of these systems when the thickness control of the insulating oxide film is crucial for device performance. A procedure is developed to directly deposit self-assembled monolayers (SAM) from solvent onto substrates prepared under ultra-high vacuum conditions without exposure to air. As an example, rhenium photosensitizers functionalized with carboxyl linker groups are attached to ultrathin alumina grown on NiAl(1 1 0). The thickness change of the oxide layer during the SAM deposition is quantified by x-ray photoelectron spectroscopy and can be drastically reduced to one atomic layer. The SAM acts as a capping layer, stabilizing the oxide thin film under environmental conditions. Ultraviolet photoelectron spectroscopy elucidates the band alignment in the resulting heterostructure. The method for molecule attachment presented in this manuscript can be extended to a broad class of molecules vulnerable to pyrolysis upon evaporation and presents an elegant method for attaching molecular layers on solid substrates that are sensitive to air.
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Affiliation(s)
- Wolf-Dietrich Zabka
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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6
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Thakur B, Zhou G, Chang J, Pu H, Jin B, Sui X, Yuan X, Yang CH, Magruder M, Chen J. Rapid detection of single E. coli bacteria using a graphene-based field-effect transistor device. Biosens Bioelectron 2018; 110:16-22. [PMID: 29579645 DOI: 10.1016/j.bios.2018.03.014] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Revised: 02/16/2018] [Accepted: 03/06/2018] [Indexed: 12/31/2022]
Abstract
Contamination of surface and drinking water due to the presence of Escherichia coli bacteria is a major cause of water-borne disease outbreak. To address unmet challenges for practical pathogen detection in contaminated samples, we report fabrication of thermally reduced graphene oxide-based field-effect transistor (rGO FET) passivated with an ultrathin layer of Al2O3 for real-time detection of E. coli bacteria. The sensor could detect a single E. coli cell within 50 s in a 1 µL sample volume. The ultrathin layer of Al2O3 acted as a barrier between rGO and potential interferents present in the sample. E. coli specific antibodies anchored on gold nanoparticles acted as probes for selective capture of E. coli. The high density of negative charge on the surface of E. coli cells strongly modulates the concentration of majority charge carriers in the rGO monolayer, thereby allowing real-time monitoring of E. coli concentration in a given sample. With a low detection limit of single cell, the FET sensor had a linear range of 1-100 CFU in 1 µL volume of sample (i.e., 103 to 105 CFU/ mL). The biosensor with good selectivity and rapid detection was further successfully demonstrated for E. coli sensing in river water. The rGO-based FET sensor provides a low cost and label-free approach, and can be mass produced for detection of a broad spectrum of pathogens in water or other liquid media.
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Affiliation(s)
- Bhawana Thakur
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Guihua Zhou
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Jingbo Chang
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Haihui Pu
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Bing Jin
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Xiaoyu Sui
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States
| | - Xiaochen Yuan
- Department of Biological Sciences, University of Wisconsin-Milwaukee, WI 53211, United States
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin-Milwaukee, WI 53211, United States
| | - Matthew Magruder
- Milwaukee Metropolitan Sewerage District, Milwaukee, WI 53211, United States
| | - Junhong Chen
- Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, United States.
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7
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Möller C, Fedderwitz H, Noguera C, Goniakowski J, Nilius N. Temperature-dependent phase evolution of copper-oxide thin-films on Au(111). Phys Chem Chem Phys 2018; 20:5636-5643. [DOI: 10.1039/c7cp08387d] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
STM and DFT calculations are employed to explore structural phase transitions in thin copper-oxide films grown on Au(111).
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Affiliation(s)
- Christoph Möller
- Carl von Ossietzky Universität Oldenburg
- Institut für Physik
- Oldenburg D-26111
- Germany
| | - Hanna Fedderwitz
- Carl von Ossietzky Universität Oldenburg
- Institut für Physik
- Oldenburg D-26111
- Germany
| | - Claudine Noguera
- CNRS
- Institut des Nanosciences de Paris
- UMR 7588
- Paris F-75005
- France
| | | | - Niklas Nilius
- Carl von Ossietzky Universität Oldenburg
- Institut für Physik
- Oldenburg D-26111
- Germany
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8
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Beniya A, Hirata H, Watanabe Y. Significant Transient Mobility of Platinum Clusters via a Hot Precursor State on the Alumina Surface. J Phys Chem Lett 2016; 7:4710-4715. [PMID: 27934209 DOI: 10.1021/acs.jpclett.6b02362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Relaxation dynamics of hot metal clusters on oxide surfaces play a crucial role in a variety of physical and chemical processes. However, their transient mobility has not been investigated as much as other systems such as atoms and molecules on metal surfaces due to experimental difficulties. To study the role of the transient mobility of clusters on the oxide surface, we investigated the initial adsorption process of size-selected Pt clusters on a thin Al2O3 film. Soft-landing the size-selected clusters while suppressing the thermal migration resulted in the transient migration controlling the initial adsorption states as an isolated and aggregated cluster, as revealed using scanning tunneling microscopy. We demonstrate that transient migration significantly contributes to the initial cluster adsorption process; the cross section for aggregation is seven times larger than the expected value from geometrical considerations, indicating that metal clusters are highly mobile during a energy dissipation process on the oxide surface.
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Affiliation(s)
- Atsushi Beniya
- Toyota Central R&D Labs., Inc. , 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
| | - Hirohito Hirata
- Toyota Motor Corporation , 1200 Mishuku, Susono, Shizuoka 410-1193, Japan
| | - Yoshihide Watanabe
- Toyota Central R&D Labs., Inc. , 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan
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9
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Mao BH, Crumlin E, Tyo EC, Pellin MJ, Vajda S, Li Y, Wang SD, Liu Z. In situ study of the electronic structure of atomic layer deposited oxide ultrathin films upon oxygen adsorption using ambient pressure XPS. Catal Sci Technol 2016. [DOI: 10.1039/c6cy00575f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
APXPS was used to investigate the effect of oxygen adsorption on the band bending and electron affinity of ALD Al2O3, ZnO and TiO2 ultrathin films.
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Affiliation(s)
- Bao-Hua Mao
- Institute of Functional Nano & Soft Materials (FUNSOM)
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices
- Soochow University
- Suzhou
- People's Republic of China
| | - Ethan Crumlin
- Advanced Light Source
- Lawrence Berkeley National Laboratory
- Berkeley
- USA
| | - Eric C. Tyo
- Materials Science Division
- Argonne National Laboratory
- Argonne
- USA
| | | | - Stefan Vajda
- Materials Science Division
- Argonne National Laboratory
- Argonne
- USA
- Nanoscience & Technology Division
| | - Yimin Li
- State Key Laboratory of Functional Materials for Informatics
- Shanghai Institute of Microsystem and Information Technology
- Chinese Academy of Sciences
- Shanghai 200050
- People's Republic of China
| | - Sui-Dong Wang
- Institute of Functional Nano & Soft Materials (FUNSOM)
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices
- Soochow University
- Suzhou
- People's Republic of China
| | - Zhi Liu
- State Key Laboratory of Functional Materials for Informatics
- Shanghai Institute of Microsystem and Information Technology
- Chinese Academy of Sciences
- Shanghai 200050
- People's Republic of China
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10
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Li YJ, Brndiar J, Naitoh Y, Sugawara Y, Štich I. Atomic force microscopy identification of Al-sites on ultrathin aluminum oxide film on NiAl(110). NANOTECHNOLOGY 2015; 26:505704. [PMID: 26588437 DOI: 10.1088/0957-4484/26/50/505704] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ultrathin alumina film formed by oxidation of NiAl(110) was studied by non-contact atomic force microscopy in an ultra high vacuum at room temperature with the quest to provide the ultimate understanding of structure and bonding of this complicated interface. Using a very stiff Si cantilever with significantly improved resolution, we have obtained images of this system with unprecedented resolution, surpassing all the previous results. In particular, we were able to unambiguously resolve all the differently coordinated aluminum atoms. This is of importance as the previous images provide very different image patterns, which cannot easily be reconciled with the existing structural models. Experiments are supported by extensive density functional theory modeling. We find that the system is strongly ionic and the atomic force microscopy images can reliably be understood from the electrostatic potential which provides an image model in excellent agreement with the experiments. However, in order to resolve the finer contrast features we have proposed a more sophisticated model based on more realistic approximants to the incommensurable alumina interface.
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Affiliation(s)
- Yan Jun Li
- Department of Applied Physics, Osaka University, Japan
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11
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Gibson AJ, Temperton RH, Handrup K, Weston M, Mayor LC, O'Shea JN. Charge transfer from an adsorbed ruthenium-based photosensitizer through an ultra-thin aluminium oxide layer and into a metallic substrate. J Chem Phys 2015; 140:234708. [PMID: 24952561 DOI: 10.1063/1.4882867] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interaction of the dye molecule N3 (cis-bis(isothiocyanato)bis(2,2-bipyridyl-4,4'-dicarbo-xylato)-ruthenium(II)) with the ultra-thin oxide layer on a AlNi(110) substrate, has been studied using synchrotron radiation based photoelectron spectroscopy, resonant photoemission spectroscopy, and near edge X-ray absorption fine structure spectroscopy. Calibrated X-ray absorption and valence band spectra of the monolayer and multilayer coverages reveal that charge transfer is possible from the molecule to the AlNi(110) substrate via tunnelling through the ultra-thin oxide layer and into the conduction band edge of the substrate. This charge transfer mechanism is possible from the LUMO+2 and 3 in the excited state but not from the LUMO, therefore enabling core-hole clock analysis, which gives an upper limit of 6.0 ± 2.5 fs for the transfer time. This indicates that ultra-thin oxide layers are a viable material for use in dye-sensitized solar cells, which may lead to reduced recombination effects and improved efficiencies of future devices.
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Affiliation(s)
- Andrew J Gibson
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Robert H Temperton
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Karsten Handrup
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Matthew Weston
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Louise C Mayor
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - James N O'Shea
- School of Physics and Astronomy and Nottingham Nanotechnology and Nanoscience Centre (NNNC), University of Nottingham, Nottingham NG7 2RD, United Kingdom
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12
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Sugumaran S, Bellan CS, Nadimuthu M. Characterization of composite PVA–Al2O3 thin films prepared by dip coating method. IRANIAN POLYMER JOURNAL 2015. [DOI: 10.1007/s13726-014-0300-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Chemical Composition and Surface Roughness of AlOx-Controlled Activity of Pt/AlOx Thin Film Catalysts for Methanol Oxidation Reaction. Catal Letters 2014. [DOI: 10.1007/s10562-014-1331-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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14
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Lee J, Perdue SM, Rodriguez Perez A, Apkarian VA. Vibronic motion with joint angstrom-femtosecond resolution observed through Fano progressions recorded within one molecule. ACS NANO 2014; 8:54-63. [PMID: 24261832 DOI: 10.1021/nn405335h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Electroluminescence (EL) in scanning tunneling microscopy (STM), which enables spectroscopy with submolecular spatial resolution, is shown to be due to radiative ionization with vibronic shape resonances that carry Fano line profiles. Since Fano progressions retain phase information, the spectra can be transformed to the time domain to reconstruct the vibronic motion. In effect, measurements within a molecule are accessible with joint space-time resolution at the Å-fs limit. We demonstrate this through EL-STM on the Jahn-Teller-active Zn-etioporphyrin radical anion and visualize the orbiting motion of scattered electrons upon sudden reduction and oxidation. We discuss the elements that enable spectroscopy with submolecular spatial resolution through EL-STM and the closely related STM-Raman process.
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Affiliation(s)
- Joonhee Lee
- Department of Chemistry, University of California , Irvine, California 92697-2025, United States
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15
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Beniya A, Isomura N, Hirata H, Watanabe Y. Morphology and chemical states of size-selected Ptnclusters on an aluminium oxide film on NiAl(110). Phys Chem Chem Phys 2014; 16:26485-92. [DOI: 10.1039/c4cp01767f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Size-selected Ptnclusters on the Al2O3surface form two-dimensional planar structures atn≤ 18 and three-dimensional two-layer structures start to appear atn≥ 19. They are composed of neutral and cationic Pt atoms.
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16
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Lateral displacement in soft-landing process and electronic properties of size-selected Pt7 clusters on the aluminum oxide film on NiAl(110). Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.05.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Surnev S, Fortunelli A, Netzer FP. Structure-property relationship and chemical aspects of oxide-metal hybrid nanostructures. Chem Rev 2012; 113:4314-72. [PMID: 23237602 DOI: 10.1021/cr300307n] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Svetlozar Surnev
- Surface and Interface Physics, Institute of Physics, Karl-Franzens University, Graz A-8010 Graz, Austria
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18
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Ning Z, Polanyi JC. Charge Delocalization Induces Reaction in Molecular Chains at a Surface. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201207819] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Ning Z, Polanyi JC. Charge Delocalization Induces Reaction in Molecular Chains at a Surface. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/anie.201207819] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Sobota M, Schernich S, Schulz H, Hieringer W, Paape N, Wasserscheid P, Görling A, Laurin M, Libuda J. Preparation and characterization of ultrathin [Ru(CO)3Cl2]2 and [BMIM][Tf2N] films on Al2O3/NiAl(110) under UHV conditions. Phys Chem Chem Phys 2012; 14:10603-12. [PMID: 22760015 DOI: 10.1039/c2cp40697g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Towards a better understanding of the interface chemistry of ionic liquid (IL) thin film catalytic systems we have applied a rigorous surface science model approach. For the first time, a model homogeneous catalyst has been prepared under ultrahigh vacuum conditions. The catalyst, di-μ-chlorobis(chlorotricarbonylruthenium) [Ru(CO)(3)Cl(2)](2), and the solvent, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf(2)N], have been deposited by physical vapor deposition onto an alumina model support [Al(2)O(3)/NiAl(110)]. First, the interaction between thin films of [Ru(CO)(3)Cl(2)](2) and the support is investigated. Then, the ruthenium complex is co-deposited with the IL and the influence of the solvent on the catalyst is discussed. D(2)O, which is a model reactant, is further added. Growth, surface interactions, and mutual interactions in the thin films are studied with IRAS in combination with density functional (DFT) calculations. At 105 K, molecular adsorption of [Ru(CO)(3)Cl(2)](2) is observed on Al(2)O(3)/NiAl(110). The IRAS spectra of the binary [Ru(CO)(3)Cl(2)](2) + [BMIM][Tf(2)N] and ternary [Ru(CO)(3)Cl(2)](2) + [BMIM][Tf(2)N] + D(2)O show every characteristic band of the individual components. Above 223 K, partial decomposition of the ruthenium complex leads to species of molecular nature attributed to Ru(CO) and Ru(CO)(2) surface species. Formation of metallic ruthenium clusters occurs above 300 K and the model catalyst decomposes further at higher temperatures. Neither the presence of the IL nor of D(2)O prevents this partial decomposition of [Ru(CO)(3)Cl(2)](2) on alumina.
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Affiliation(s)
- Marek Sobota
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, D-91058 Erlangen, Germany
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21
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Han Y, Unal B, Evans JW. Formation of a novel ordered Ni3Al surface structure by codeposition on NiAl(110). PHYSICAL REVIEW LETTERS 2012; 108:216102. [PMID: 23003283 DOI: 10.1103/physrevlett.108.216102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 06/01/2023]
Abstract
The formation of a new type of ordered 2D Ni3Al overlayer by low-temperature codeposition on NiAl(110) is demonstrated by kinetic Monte Carlo simulation of a multisite atomistic lattice-gas model with a precise treatment of surface diffusion kinetics. Simultaneous codeposition with 3:1 Ni:Al yields poor ordering at 300 K but well-ordered structures by ~500 K. Sequential codeposition of Ni then Al yields unmixed core-ring nanostructures at 300 K but strong intermixing and ordering by ~500 K.
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Affiliation(s)
- Yong Han
- Institute for Physical Research and Technology, Iowa State University, Ames, Iowa 50011, USA.
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22
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Simon GH, Heyde M, Freund HJ. Imaging and manipulation of adatoms on an alumina surface by noncontact atomic force microscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:084007. [PMID: 22310328 DOI: 10.1088/0953-8984/24/8/084007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Noncontact atomic force microscopy (NC-AFM) has been performed on an aluminum oxide film grown on NiAl(110) in ultrahigh vacuum (UHV) at low temperature (5 K). Results reproduce the topography of the structural model, unlike scanning tunnelling microscopy (STM) images. Equipped with this extraordinary contrast the network of extended defects, which stems from domain boundaries intersecting the film surface, can be analysed in atomic detail. The knowledge of occurring surface structures opens up the opportunity to determine adsorption sites of individual adsorbates on the alumina film. The level of difficulty for such imaging depends on the imaging characteristics of the substrate and the interaction which can be maintained above the adsorbate. Positions of single adsorbed gold atoms within the unit cell have been determined despite their easy removal at slightly higher interaction strength. Preliminary manipulation experiments indicate a pick-up process for the vanishing of the gold adatoms from the film surface.
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Affiliation(s)
- G H Simon
- Fritz-Haber-Institute of the Max-Planck-Society, Department of Chemical Physics, Berlin, Germany
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Nilius N, Kozlov SM, Jerratsch JF, Baron M, Shao X, Viñes F, Shaikhutdinov S, Neyman KM, Freund HJ. Formation of one-dimensional electronic states along the step edges of CeO₂(111). ACS NANO 2012; 6:1126-33. [PMID: 22206297 DOI: 10.1021/nn2036472] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Scanning tunneling microscopy (STM) combined with density functional theory (DFT) are used to analyze the structural and electronic properties of step edges on the surface of CeO(2)(111) films grown on Ru(0001). Depending on the preparation conditions, 211 or 110-oriented steps develop on the surface, which results in the formation of ceria ad-islands with hexagonal or triangular shapes. STM conductance spectroscopy reveals pronounced differences in the electronic properties of the step edges, as reflected in different onset positions of the ceria conduction band. The band shifts are related to the development of distinct edge electronic states that split-off from the ceria conduction band, as shown with DFT calculations. The separation of the edge states from the main band is governed by the atom-coordination and local charge-distribution along the edge, the latter giving rise to the development of electrostatic dipoles. We expect that the observed edge morphologies determine not only the electronic properties but also the adsorption behavior of step edges on the CeO(2)(111) surface.
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Affiliation(s)
- Niklas Nilius
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
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24
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Zhou J, Zhou J, Camillone N, White MG. Electronic charging of non-metallic clusters: size-selected MoxSy clusters supported on an ultrathin alumina film on NiAl(110). Phys Chem Chem Phys 2012; 14:8105-10. [DOI: 10.1039/c2cp40921f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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25
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Steinrück HP, Libuda J, Wasserscheid P, Cremer T, Kolbeck C, Laurin M, Maier F, Sobota M, Schulz PS, Stark M. Surface science and model catalysis with ionic liquid-modified materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:2571-2587. [PMID: 21520462 DOI: 10.1002/adma.201100211] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Indexed: 05/30/2023]
Abstract
Materials making use of thin ionic liquid (IL) films as support-modifying functional layer open up a variety of new possibilities in heterogeneous catalysis, which range from the tailoring of gas-surface interactions to the immobilization of molecularly defined reactive sites. The present report reviews recent progress towards an understanding of "supported ionic liquid phase (SILP)" and "solid catalysts with ionic liquid layer (SCILL)" materials at the microscopic level, using a surface science and model catalysis type of approach. Thin film IL systems can be prepared not only ex-situ, but also in-situ under ultrahigh vacuum (UHV) conditions using atomically well-defined surfaces as substrates, for example by physical vapor deposition (PVD). Due to their low vapor pressure, these systems can be studied in UHV using the full spectrum of surface science techniques. We discuss general strategies and considerations of this approach and exemplify the information available from complementary methods, specifically photoelectron spectroscopy and surface vibrational spectroscopy.
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Affiliation(s)
- H-P Steinrück
- Lehrstuhl für Physikalische Chemie 2 and Erlangen Catalysis, Resource Center, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
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26
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Shao X, Jerratsch JF, Nilius N, Freund HJ. Probing the 4f states of ceria by tunneling spectroscopy. Phys Chem Chem Phys 2011; 13:12646-51. [PMID: 21674086 DOI: 10.1039/c1cp21113g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Low-temperature scanning tunneling microscopy and spectroscopy have been employed to analyze the local electronic structure of the (111) surface of a ceria thin film grown on Ru(0001). On pristine, defect-free oxide terraces, the empty 4f states of Ce(4+) ions appear as the only spectral feature inside the 6 eV oxide band gap. In contrast, occupied states are detected between -1.0 and -1.5 eV below E(Fermi) in conductance spectra of different point and line defects, such as surface oxygen vacancies, grain boundaries and step edges. They are assigned to partially filled 4f states localized at the Ce(3+) ions. The presence of excess electrons indicates the oxygen-deficient nature of the direct oxide environment. The f state spectroscopy with the STM allows us to probe the spatial distribution of Ce(3+) ions in the ceria surface, providing unique insight into the local reduction state of this chemically important material system.
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Affiliation(s)
- Xiang Shao
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany
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27
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König T, Simon GH, Heinke L, Lichtenstein L, Heyde M. Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:1-14. [PMID: 21977410 PMCID: PMC3045939 DOI: 10.3762/bjnano.2.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 12/09/2010] [Indexed: 05/24/2023]
Abstract
Surfaces of thin oxide films were investigated by means of a dual mode NC-AFM/STM. Apart from imaging the surface termination by NC-AFM with atomic resolution, point defects in magnesium oxide on Ag(001) and line defects in aluminum oxide on NiAl(110), respectively, were thoroughly studied. The contact potential was determined by Kelvin probe force microscopy (KPFM) and the electronic structure by scanning tunneling spectroscopy (STS). On magnesium oxide, different color centers, i.e., F(0), F(+), F(2+) and divacancies, have different effects on the contact potential. These differences enabled classification and unambiguous differentiation by KPFM. True atomic resolution shows the topography at line defects in aluminum oxide. At these domain boundaries, STS and KPFM verify F(2+)-like centers, which have been predicted by density functional theory calculations. Thus, by determining the contact potential and the electronic structure with a spatial resolution in the nanometer range, NC-AFM and STM can be successfully applied on thin oxide films beyond imaging the topography of the surface atoms.
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Affiliation(s)
- Thomas König
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Georg H Simon
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Lars Heinke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Leonid Lichtenstein
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Markus Heyde
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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28
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Burow AM, Wende T, Sierka M, Włodarczyk R, Sauer J, Claes P, Jiang L, Meijer G, Lievens P, Asmis KR. Structures and vibrational spectroscopy of partially reduced gas-phase cerium oxide clusters. Phys Chem Chem Phys 2011; 13:19393-400. [DOI: 10.1039/c1cp22129a] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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29
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Heinke L, Lichtenstein L, Simon GH, König T, Heyde M, Freund HJ. Local work function differences at line defects in aluminium oxide on NiAl(110). Chemphyschem 2010; 11:2085-7. [PMID: 20544778 DOI: 10.1002/cphc.201000060] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lars Heinke
- Fritz-Haber-Institute of the Max-Planck-Society, Faradayweg 4-6, 14195 Berlin, Germany
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30
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Sobota M, Nikiforidis I, Hieringer W, Paape N, Happel M, Steinrück HP, Görling A, Wasserscheid P, Laurin M, Libuda J. Toward ionic-liquid-based model catalysis: growth, orientation, conformation, and interaction mechanism of the [Tf2N]- anion in [BMIM][Tf2N] thin films on a well-ordered alumina surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:7199-207. [PMID: 20143797 DOI: 10.1021/la904319h] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Aiming at a better understanding of the interaction of ionic liquid (IL) thin films with oxide supports, we have performed a model study under ultrahigh vacuum (UHV) conditions. We apply infrared reflection absorption spectroscopy (IRAS) in combination with density functional theory (DFT). Thin films of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf(2)N] are grown on an atomically flat, well-ordered alumina film on NiAl(110) using a novel UHV-compatible evaporator. Time-resolved IRAS measured during the growth and subsequent thermal desorption points toward reversible molecular adsorption and desorption. There was no indication of decomposition. The vibrational bands are assigned with the help of DFT calculations. Strong relative intensity changes in individual [Tf(2)N](-) bands are observed in the monolayer region. This indicates pronounced orientation effects for the anion. The adsorption geometry of [Tf(2)N](-) is determined on the basis of a detailed comparison with DFT. The results suggest that [Tf(2)N](-) anions adopt a cis conformation in the submonolayer region. They adsorb in a slightly tilted orientation with respect to the surface, mainly interacting with the support via the sulfonyl groups.
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Affiliation(s)
- Marek Sobota
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany
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31
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Abstract
Most metals are oxidized under ambient conditions, and metal oxides show interesting and technologically promising properties. This has motivated much recent research on oxide surfaces. The combination of scanning tunneling microscopy with first-principles density functional theory–based computational techniques provides an atomic-scale view of the properties of metal-oxide materials. Surface polarity is a key concept for predicting the stability of oxide surfaces and is discussed using ZnO as an example. This review also highlights the role of surface defects for surface reactivity, and their interplay with defects in the bulk, for the case of TiO2. Ultrathin metal-oxide films, grown either through reactive evaporation on metal single crystals or through oxidation of metal alloys (such as Al2O3/NiAl), have gained popularity as supports for planar model catalysts. The surface oxides that form upon oxidation on Pt-group metals (e.g., Ru, Rh, Pd, and Pt) are considered as model systems for CO oxidation.
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Affiliation(s)
- Ulrike Diebold
- Department of Physics, Tulane University, New Orleans, Louisiana 70118
| | - Shao-Chun Li
- Department of Physics, Tulane University, New Orleans, Louisiana 70118
| | - Michael Schmid
- Institut für Allgemeine Physik, Technische Universität Wien, A-1040 Vienna, Austria
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32
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Kukkola J, Rautio A, Sala G, Pino F, Tóth G, Leino AR, Mäklin J, Jantunen H, Uusimäki A, Kordás K, Gracia E, Terrones M, Shchukarev A, Mikkola JP. Electrical transport through single-wall carbon nanotube-anodic aluminum oxide-aluminum heterostructures. NANOTECHNOLOGY 2010; 21:035707. [PMID: 19966389 DOI: 10.1088/0957-4484/21/3/035707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Aluminum foils were anodized in sulfuric acid solution to form thick porous anodic aluminum oxide (AAO) films of thickness approximately 6 microm. Electrodes of carboxyl-functionalized single-wall carbon nanotube (SWCNT) thin films were inkjet printed on the anodic oxide layer and the electrical characteristics of the as-obtained SWCNT-AAO-Al structures were studied. Nonlinear current-voltage transport and strong temperature dependence of conduction through the structure was measured. The microstructure and chemical composition of the anodic oxide layer was analyzed using transmission and scanning electron microscopy as well as x-ray photoelectron spectroscopy. Schottky emission at the SWCNT-AAO and AAO-Al interfaces allowed by impurity states in the anodic aluminum oxide film together with ionic surface conduction on the pore walls of AAO gives a reasonable explanation for the measured electrical conduction. Calcined AAO is proposed as a dielectric material for SWCNT-field effect transistors.
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Affiliation(s)
- Jarmo Kukkola
- Department of Electrical and Information Engineering, University of Oulu, Finland.
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33
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Sobota M, Schmid M, Happel M, Amende M, Maier F, Steinrück HP, Paape N, Wasserscheid P, Laurin M, Gottfried JM, Libuda J. Ionic liquid based model catalysis: interaction of [BMIM][Tf2N] with Pd nanoparticles supported on an ordered alumina film. Phys Chem Chem Phys 2010; 12:10610-21. [DOI: 10.1039/c003753b] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Sierka M, Döbler J, Sauer J, Zhai HJ, Wang LS. The [(Al2O3)2]−Anion Cluster: Electron Localization-Delocalization Isomerism. Chemphyschem 2009; 10:2410-3. [DOI: 10.1002/cphc.200900460] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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35
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Wu QH, Fortunelli A, Granozzi G. Preparation, characterisation and structure of Ti and Al ultrathin oxide films on metals. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903172453] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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36
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Schmal M, Freund HJ. Towards an atomic level understanding of niobia based catalysts and catalysis by combining the science of catalysis with surface science. AN ACAD BRAS CIENC 2009. [DOI: 10.1590/s0001-37652009000200016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The science of catalysis and surface science have developed, independently, key information for understanding catalytic processes. One might argue: is there anything fundamental to be discovered through the interplay between catalysis and surface science? Real catalysts of monometallic and bimetallic Co/Nb2O5 and Pd-Co/Nb2O5 catalysts showed interesting selectivity results on the Fischer-Tropsch synthesis (Noronha et al. 1996, Rosenir et al. 1993). The presence of a noble metal increased the C+5 selectivity and decreased the methane formation depending of the reduction temperature. Model catalyst of Co-Pd supported on niobia and alumina were prepared and characterized at the atomic level, thus forming the basis for a comparison with "real" support materials. Growth, morphology and structure of both pure metal and alloy particles were studied. It is possible to support the strong metal support interaction suggested by studies on real catalysts via the investigation of model systems for niobia in comparison to alumina support in which this effect does not occur. Formation of Co2+ penetration into the niobia lattice was suggested on the basis of powder studies and can be fully supported on the basis of model studies. It is shown for both real catalysts and model systems that oxidation state of Co plays a key role in controlling the reactivity in Fischer-Tropsch reactions systems and that the addition of Pd is a determining factor for the stability of the catalyst. It is demonstrated that the interaction with unsaturated hydrocarbons depends strongly on the state of oxidation.
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37
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Tao X, Dong ZC, Yang JL, Luo Y, Hou JG, Aizpurua J. Influence of a dielectric layer on photon emission induced by a scanning tunneling microscope. J Chem Phys 2009; 130:084706. [DOI: 10.1063/1.3080766] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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38
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Bertolini JC. Model catalysis by metals and alloys: From single-crystal surfaces to well-defined nano-particles. Catal Today 2008. [DOI: 10.1016/j.cattod.2008.04.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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39
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Hafner J. Ab-initiosimulations of materials using VASP: Density-functional theory and beyond. J Comput Chem 2008; 29:2044-78. [DOI: 10.1002/jcc.21057] [Citation(s) in RCA: 1810] [Impact Index Per Article: 113.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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40
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Nilius N, Ganduglia-Pirovano MV, Brázdová V, Kulawik M, Sauer J, Freund HJ. Counting electrons transferred through a thin alumina film into Au chains. PHYSICAL REVIEW LETTERS 2008; 100:096802. [PMID: 18352741 DOI: 10.1103/physrevlett.100.096802] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Indexed: 05/26/2023]
Abstract
Low-temperature STM measurements combined with density functional theory calculations are employed to study the adsorption of gold on alumina/NiAl(110). The binding of Au monomers involves breaking of an oxide Al-O bond below the adatom and stabilizing the hence undercoordinated O ion by forming a new bond to an Al atom in the NiAl. The adsorption implies negative charging of the adatom. The linear arrangement of favorable binding sites induces the self-organization of Au atoms into chains. For every ad-chain, the number of transfer electrons from the support is determined by analyzing the node structure of the corresponding highest occupied molecular orbital.
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Affiliation(s)
- N Nilius
- Fritz-Haber-Institut der MPG, Faradayweg 4-6, Berlin, Germany.
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41
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Freund HJ, Pacchioni G. Oxide ultra-thin films on metals: new materials for the design of supported metal catalysts. Chem Soc Rev 2008; 37:2224-42. [DOI: 10.1039/b718768h] [Citation(s) in RCA: 467] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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42
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Barcaro G, Fortunelli A, Granozzi G. Metal adsorption on oxide polar ultrathin films. Phys Chem Chem Phys 2008; 10:1876-82. [DOI: 10.1039/b719346g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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43
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Schmid M, Kresse G, Buchsbaum A, Napetschnig E, Gritschneder S, Reichling M, Varga P. Nanotemplate with holes: ultrathin alumina on Ni3Al(111). PHYSICAL REVIEW LETTERS 2007; 99:196104. [PMID: 18233088 DOI: 10.1103/physrevlett.99.196104] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Indexed: 05/25/2023]
Abstract
We have determined the structure of the ultrathin (sqrt[67] x sqrt[67])R12.2 degrees aluminum oxide on Ni3Al(111) by a combination of scanning tunneling microscopy and density functional theory. In addition to other local defects, the main structural feature of the unit cell is a 0.4-nm-diameter hole reaching down to the metal substrate. Understanding the structure and metal growth on this oxide allows us to use it as a template for growing highly regular arrays of nanoparticles.
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Affiliation(s)
- M Schmid
- Institut für Allgemeine Physik, Technische Universität Wien, 1040, Wien, Austria
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44
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