1
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Martínez-Galera AJ, Molina-Motos R, Gómez-Rodríguez JM. Unearthing Atomic Dynamics in Nanocatalysts. ACS APPLIED MATERIALS & INTERFACES 2024. [PMID: 39453444 DOI: 10.1021/acsami.4c14382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2024]
Abstract
Being able to access the rich atomic-scale phenomenology, which occurs during the reactions pathways, is a pressing need toward the pursued knowledge-based design of more efficient nanocatalysts, precisely tailored atom by atom for each reaction. However, to reach this goal of achieving maximum optimization, it is mandatory, first, to address how exposure to the experimental conditions, which will be needed to activate the processes, affects the internal configuration of the nanoparticles at the atomic level. In particular, the most critical experimental parameter is probably the temperature, which among other unwanted effects can induce nanocatalyst aggregation. This work highlights the high potential of experimental techniques such as the scanning probe microscopies, which are able to investigate matter in real space with atomic resolution, to reach the key challenge in heterogeneous catalysis of achieving access to the atomic-scale processes taking place in the nanocatalysts. Specifically, the phenomenology occurring in a nanoparticle system during annealing is studied with atomic precision by scanning tunneling microscopy. As a result, the existence of an internal atomic restructuring, occurring already at relatively low temperatures, within Ir nanoparticles grown over h-BN/Ru(0001) surfaces is demonstrated. Such restructuration, which reduces the undercoordination of the outer Ir atoms, is expected to have a significant effect on the reactivity of the nanoparticles. Going a step further, an internal restructuring of the nanoparticles during their involvement as catalysts has also been also identified.
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Affiliation(s)
- Antonio J Martínez-Galera
- Departamento de Física de Materiales, Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - Rocío Molina-Motos
- Departamento de Física de Materiales, Universidad Autónoma de Madrid, Madrid E-28049, Spain
| | - José M Gómez-Rodríguez
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid E-28049, Spain
- Departamento de Física de la Materia condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
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2
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Tian Q, Izadi Vishkayi S, Bagheri Tagani M, Zhang L, Tian Y, Yin LJ, Zhang L, Qin Z. Two-Dimensional Artificial Ge Superlattice Confining in Electronic Kagome Lattice Potential Valleys. NANO LETTERS 2023; 23:9851-9857. [PMID: 37871176 DOI: 10.1021/acs.nanolett.3c02674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Constructing two-dimensional (2D) artificial superlattices based on single-atom and few-atom nanoclusters is of great interest for exploring exotic physics. Here we report the realization of two types of artificial germanium (Ge) superlattice self-confined by a 37 × 37 R25.3° superstructure of bismuth (Bi) induced electronic kagome lattice potential valleys. Scanning tunneling microscopy measurements demonstrate that Ge atoms prefer to be confined in the center of the Bi electronic kagome lattice, forming a single-atom superlattice at 120 K. In contrast, room temperature grown Ge atoms and clusters are confined in the sharing triangle corner and the center, respectively, of the kagome lattice potential valleys, forming an artificial honeycomb superlattice. First-principle calculations and Mulliken population analysis corroborate that our reported atomically thin Bi superstructure on Au(111) has a kagome surface potential valley with the center of the inner Bi hexagon and the space between the outer Bi hexagons being energetically favorable for trapping Ge atoms.
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Affiliation(s)
- Qiwei Tian
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Sahar Izadi Vishkayi
- School of Physics, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
| | - Meysam Bagheri Tagani
- Department of Physics, University of Guilan, P.O. Box 41335-1914, Rasht 32504550, Iran
| | - Li Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yuan Tian
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Long-Jing Yin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Lijie Zhang
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Zhihui Qin
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
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3
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Surana M, Ananthakrishnan G, Poss MM, Yaacoub JJ, Zhang K, Ahmed T, Admal NC, Pochet P, Johnson HT, Tawfick S. Strain-Driven Faceting of Graphene-Catalyst Interfaces. NANO LETTERS 2023; 23:1659-1665. [PMID: 36745111 DOI: 10.1021/acs.nanolett.2c03911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The interfacial interaction of 2D materials with the substrate leads to striking surface faceting affecting its electronic properties. Here, we quantitatively study the orientation-dependent facet topographies observed on the catalyst under graphene using electron backscatter diffraction and atomic force microscopy. The original flat catalyst surface transforms into two facets: a low-energy low-index surface, e.g. (111), and a vicinal (high-index) surface. The critical role of graphene strain, besides anisotropic interfacial energy, in forming the observed topographies is revealed by molecular simulations. These insights are applicable to other 2D/3D heterostructures.
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Affiliation(s)
- Mitisha Surana
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Ganesh Ananthakrishnan
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Matthew M Poss
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Jad Jean Yaacoub
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Kaihao Zhang
- The Hong Kong University of Science and Technology, Guangzhou999077, Hong Kong, China
| | - Tusher Ahmed
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Nikhil Chandra Admal
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Pascal Pochet
- Department of Physics, IriG, Univ. Grenoble-Alpes and CEA, GrenobleF-38054, France
| | - Harley T Johnson
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
| | - Sameh Tawfick
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana61801, Illinois, USA
- The Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois61801, USA
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4
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Mondal M, Ganapathy R. Hierarchical Colloidal Self-Assembly on Lattice-Mismatched Moiré Patterns. J Phys Chem Lett 2023; 14:619-626. [PMID: 36633917 DOI: 10.1021/acs.jpclett.2c03540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Extending atomic epitaxy concepts to colloidal systems for realizing functional surface structures has recently piqued scientific interest. Akin to the growth of ordered metal clusters on graphene moiré, spatially ordered colloidal crystals have been realized on soft lithographically fabricated moiré patterns. In addition to moiré periodicity, lattice misfit strain can bring about a further level of hierarchy in colloidal self-assembly, although its role in self-organization remains unexplored. Here, we demonstrate the self-organized growth of micrometer-sized colloidal pyramid arrays with lateral order extending over millimeter length scales on lattice-mismatched moiré patterns. By probing the film growth dynamics with single-particle resolution, we uncovered the interplay between lattice misfit strain and topographically varying surface potential within the moiré unit cell, which significantly alters the nucleation process. We also show that the structural organization of colloids within moiré regions primarily depends on the moiré angle, and by tuning it, multiple levels of hierarchy can be achieved.
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Affiliation(s)
- Manodeep Mondal
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore560064, India
| | - Rajesh Ganapathy
- International Centre for Materials Science, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore560064, India
- School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore560064, India
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5
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Graphene-based electrode materials used for some pesticide’s detection in food samples: A review. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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6
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Boix V, Xu W, D’Acunto G, Stubbe J, Gallo T, Døvre Strømsheim M, Zhu S, Scardamaglia M, Shavorskiy A, Reuter K, Andersen M, Knudsen J. Graphene as an Adsorption Template for Studying Double Bond Activation in Catalysis. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:14116-14124. [PMID: 36060283 PMCID: PMC9425632 DOI: 10.1021/acs.jpcc.2c02293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Hydrogenated graphene (H-Gr) is an extensively studied system not only because of its capabilities as a simplified model system for hydrocarbon chemistry but also because hydrogenation is a compelling method for Gr functionalization. However, knowledge of how H-Gr interacts with molecules at higher pressures and ambient conditions is lacking. Here we present experimental and theoretical evidence that room temperature O2 exposure at millibar pressures leads to preferential removal of H dimers on H-functionalized graphene, leaving H clusters on the surface. Our density functional theory (DFT) analysis shows that the removal of H dimers is the result of water or hydrogen peroxide formation. For water formation, we show that the two H atoms in the dimer motif attack one end of the physisorbed O2 molecule. Moreover, by comparing the reaction pathways in a vacuum with the ones on free-standing graphene and on the graphene/Ir(111) system, we find that the main role of graphene is to arrange the H atoms in geometrical positions, which facilitates the activation of the O=O double bond.
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Affiliation(s)
- Virginia Boix
- Division
of Synchrotron Radiation Research, Department of Physics, Lund University, Sölvegatan 14, 22362 Lund, Sweden
- NanoLund, Lund University, Professorsgatan 1, 22362 Lund, Sweden
| | - Wenbin Xu
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
- Chair
for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, D-85748 Garching, Germany
| | - Giulio D’Acunto
- Division
of Synchrotron Radiation Research, Department of Physics, Lund University, Sölvegatan 14, 22362 Lund, Sweden
- NanoLund, Lund University, Professorsgatan 1, 22362 Lund, Sweden
| | - Johannes Stubbe
- Division
of Synchrotron Radiation Research, Department of Physics, Lund University, Sölvegatan 14, 22362 Lund, Sweden
| | - Tamires Gallo
- Division
of Synchrotron Radiation Research, Department of Physics, Lund University, Sölvegatan 14, 22362 Lund, Sweden
| | - Marie Døvre Strømsheim
- Department
of Chemical Engineering, Norwegian University
of Science and Technology, Trondheim 7034, Norway
| | - Suyun Zhu
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
| | | | - Andrey Shavorskiy
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
| | - Karsten Reuter
- Fritz-Haber-Institut
der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Mie Andersen
- Aarhus Institute
of Advanced Studies, Aarhus University, Aarhus C DK-8000, Denmark
- Department
of Physics and Astronomy - Center for Interstellar Catalysis, Aarhus University, Aarhus C DK-8000, Denmark
| | - Jan Knudsen
- Division
of Synchrotron Radiation Research, Department of Physics, Lund University, Sölvegatan 14, 22362 Lund, Sweden
- NanoLund, Lund University, Professorsgatan 1, 22362 Lund, Sweden
- MAX IV Laboratory, Lund University, Fotongatan 2, 22484 Lund, Sweden
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7
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Kraus S, Herman A, Huttmann F, Krämer C, Amsharov K, Tsukamoto S, Wende H, Atodiresei N, Michely T. Selecting the Reaction Path in On-Surface Synthesis through the Electron Chemical Potential in Graphene. J Am Chem Soc 2022; 144:11003-11009. [PMID: 35695094 DOI: 10.1021/jacs.2c04359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The organometallic on-surface synthesis of the eight-membered sp2 carbon-based ring cyclooctatetraene (C8H8, Cot) with the neighboring rare-earth elements ytterbium and thulium yields fundamentally different products for the two lanthanides, when conducted on graphene (Gr) close to the charge neutrality point. Sandwich-molecular YbCot wires of more than 500 Å length being composed of an alternating sequence of Yb atoms and upright-standing Cot molecules result from the on-surface synthesis with Yb. In contrast, repulsively interacting TmCot dots consisting of a single Cot molecule and a single Tm atom result from the on-surface synthesis with Tm. While the YbCot wires are bound through van der Waals interactions to the substrate, the dots are chemisorbed to Gr via the Tm atoms being more electropositive compared to Yb atoms. When the electron chemical potential in Gr is substantially raised (n-doping) through backside doping from an intercalation layer, the reaction product in the synthesis with Tm can be tuned to TmCot sandwich-molecular wires rather than TmCot dots. By use of density functional theory, it is found that the reduced electronegativity of Gr upon n-doping weakens the binding as well as the charge transfer between the reaction intermediate TmCot dot and Gr. Thus, the assembly of the TmCot dots to long TmCot sandwich-molecular wires becomes energetically favorable. It is thereby demonstrated that the electron chemical potential in Gr can be used as a control parameter in an organometallic on-surface synthesis to tune the outcome of a reaction.
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Affiliation(s)
- Stefan Kraus
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Alexander Herman
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany
| | - Felix Huttmann
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Christian Krämer
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Konstantin Amsharov
- Institute of Chemistry, Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str.2, 06120 Halle, Germany
| | - Shigeru Tsukamoto
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Heiko Wende
- Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany
| | - Nicolae Atodiresei
- Peter Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, 52428 Jülich, Germany
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
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8
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Jin C, Cheng L, Feng G, Ye R, Lu ZH, Zhang R, Yu X. Adsorption of Transition-Metal Clusters on Graphene and N-Doped Graphene: A DFT Study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3694-3710. [PMID: 35285652 DOI: 10.1021/acs.langmuir.1c03187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Using the dispersion-corrected density functional theory (DFT-D3) method, we systematically studied the adsorption of 15 kinds of transition-metal (TM) clusters on pristine graphene (Gr) and N-doped graphene (N-Gr). It has been found that TMn (n = 1-4) clusters adsorbed on the N-Gr surface are much stronger than those on the pristine Gr surface, while 3d series clusters present similar geometries on Gr and N-Gr surfaces. The most preferred sites of TMs migrate from hollow to bridge to the top site on the Gr surface along the d series in the periodic table, while the preferred sites of TMs migrate in a much more complex manner on the N-Gr surface. It has also been found that charge transfer decreases along the d series for adsorbed clusters on both surfaces, but adsorbed clusters present less charge transfer on the N-Gr surface than on the Gr surface. What is more interesting is that some TM (Tc, Ru, and Re) clusters change the growth mechanism from the three-dimensional (3D) growth mode on the Gr surface to the two-dimensional (2D) growth mode on the N-Gr surface. At last, it has been found that adsorbed clusters are more dispersed on the N-Gr surface than on the pristine Gr surface due to growth and average aggregation energies.
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Affiliation(s)
- Chengkai Jin
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, Institute of Applied Chemistry, College of Chemistry, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, P. R. China
| | - Lihong Cheng
- Key Laboratory of Surface Engineering of Jiangxi Province, Jiangxi Science & Technology Normal University, Nanchang 330031, P. R. China
| | - Gang Feng
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, Institute of Applied Chemistry, College of Chemistry, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, P. R. China
| | - Runping Ye
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, Institute of Applied Chemistry, College of Chemistry, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, P. R. China
| | - Zhang-Hui Lu
- Institute of Advanced Materials (IAM), College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang 330022, P. R. China
| | - Rongbin Zhang
- Key Laboratory of Jiangxi Province for Environment and Energy Catalysis, Institute of Applied Chemistry, College of Chemistry, Nanchang University, No. 999 Xuefu Road, Nanchang 330031, P. R. China
| | - Xiaohu Yu
- Institute of Theoretical and Computational Chemistry, Shaanxi Key Laboratory of Catalysis, School of Chemical & Environment Sciences, Shaanxi University of Technology, Hanzhong 723000, P. R. China
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9
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Abstract
Hydrogenated borophenes─borophanes─have recently been synthesized as a new platform for studying low-dimensional borides, but most of their lattice structures remain unknown. Here, we determine the structures of borophane polymorphs on Ag(111) by performing extensive structural search using the cluster expansion method augmented with first-principles calculations. Our results reveal rich borophane polymorphs whose stability depends on hydrogen pressure. At relatively low hydrogen pressures, borophane structures with rhombic patterns of two-center-two-electron B-H bonds are energetically preferred, in excellent agreement with two experimentally observed phases. In a wider range of hydrogen pressures, the structure with a combination of two-center-two-electron B-H and three-center-two-electron B-H-B bonds is a deep global minimum, rationalizing its experimental prevalence. For all these borophane polymorphs, their hydrogen "skin" raises the energy barriers for oxidation above 1.1 eV, while their work functions can be reduced by more than 0.5 eV through varying the hydrogen coverage.
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Affiliation(s)
- Ying Xu
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Peikun Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Xiaoyu Xuan
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Minmin Xue
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Zhuhua Zhang
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Wanlin Guo
- Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education, State Key Laboratory of Mechanics and Control of Mechanical Structures, and Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Boris I Yakobson
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005, United States
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10
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Model Catalysis with HOPG-Supported Pd Nanoparticles and Pd Foil: XPS, STM and C2H4 Hydrogenation. Catal Letters 2021; 152:2892-2907. [PMID: 36196216 PMCID: PMC9525433 DOI: 10.1007/s10562-021-03868-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022]
Abstract
A surface science based approach was applied to model carbon supported Pd nanoparticle catalysts. Employing physical vapour deposition of Pd on sputtered surfaces of highly oriented pyrolytic graphite (HOPG), model catalysts were prepared that are well-suited for characterization by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). Analysis of the HOPG substrate before and after ion-bombardment, and of Pd/HOPG before and after annealing, revealed the number of “nominal” HOPG defects (~ 1014 cm−2) as well as the nucleation density (~ 1012 cm−2) and structural characteristics of the Pd nanoparticles (mean size/height/distribution). Two model systems were stabilized by UHV annealing to 300 °C, with mean Pd particles sizes of 4.3 and 6.8 nm and size/height aspect ratio up to ~ 10. A UHV-compatible flow microreactor and gas chromatography were used to determine the catalytic performance of Pd/HOPG in ethylene (C2H4) hydrogenation up to 150 °C under atmospheric pressure, yielding temperature-dependent conversion values, turnover frequencies (TOFs) and activation energies. The performance of Pd nanocatalysts is compared to that of polycrystalline Pd foil and contrasted to Pt/HOPG and Pt foil, pointing to a beneficial effect of the metal/carbon phase boundary, reflected by up to 10 kJ mol−1 lower activation energies for supported nanoparticles.
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11
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Zhang L, Ding F. Mechanism of Corrugated Graphene Moiré Superstructures on Transition-Metal Surfaces. ACS APPLIED MATERIALS & INTERFACES 2021; 13:56674-56681. [PMID: 34784183 DOI: 10.1021/acsami.1c18512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A graphene layer on a transition-metal (TM) surface can be either corrugated or flat, depending on the type of the substrate and its rotation angle with respect to the substrate. It was broadly observed that the degree of corrugation generally decreases with the increase of rotation angle or the decrease of Moiré pattern size. In contrast to a flat graphene on a TM surface, a corrugated graphene layer has an increased binding energy to the substrate and a concomitant elastic energy. Here, we developed a theoretical model about the competition between the binding energy increase and the elastic energy of corrugated graphene layers on TM surfaces in which all the parameters can be calculated by density functional theory (DFT) calculations. The agreement between the theoretical model and the experimental observations of graphene on various TM surfaces, for example, Ru(0001), Rh(111), Pt(111), and Ir(111), substantiated the applicability of this model for graphene on other TM surfaces. Moreover, the morphology of a graphene layer on an arbitrary TM surface can be theoretically predicted through simple DFT calculations based on the model. Our work thus provides a theoretical framework for the intelligent design of graphene/TM superstructures with the desired structure.
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Affiliation(s)
- Leining Zhang
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Feng Ding
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
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12
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Franz D, Schröder U, Shayduk R, Arndt B, Noei H, Vonk V, Michely T, Stierle A. Hydrogen Solubility and Atomic Structure of Graphene Supported Pd Nanoclusters. ACS NANO 2021; 15:15771-15780. [PMID: 34633788 DOI: 10.1021/acsnano.1c01997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We investigated the atomic structure of graphene supported Pd nanoclusters and their interaction with hydrogen up to atmospheric pressures at room temperature by surface X-ray diffraction and scanning tunneling microscopy. We find that Ir seeded Pd nanocluster superlattices with 1.2 nm cluster diameters can be grown on the graphene/Ir(111) moiré template with high structural perfection. The superlattice clusters are anchored through the rehybridized graphene to the Ir support, which superimposes a 2.0% inplane compression onto the clusters. During hydrogen exposure at 10 mbar pressure and room temperature, a significant part of the clusters gets unpinned from the superlattice. The clusters in registry undergo an out-of-plane expansion only, whereas the detached clusters expand in in- and out-of-plane directions. The formation of a hydrogen rich PdHx α' phase was not observed. After exposure to 1 bar, the majority of the clusters are unpinned from superlattice sites, due to their surface interaction with hydrogen and possible spill over to the graphene support. Only minor sintering was observed, which is more pronounced for the unpinned clusters. The results give evidence that ultrasmall Pd clusters on graphene are a stable hydrogen storage system with reduced hydrogen storage hysteresis and maintain a large surface area for hydrogen chemisorption.
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Affiliation(s)
- Dirk Franz
- Deutsches Elektronen-Synchrotron (DESY), Hamburg, D-22607 Germany
- Physics Department, University of Hamburg, Hamburg, D-20355 Germany
| | - Ulrike Schröder
- Institute of Physics II, University of Cologne, Cologne, D-50937 Germany
| | - Roman Shayduk
- Deutsches Elektronen Synchrotron (DESY), Hamburg, D-22607 Germany
| | - Björn Arndt
- Physics Department, University of Hamburg, Hamburg, D-20355 Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, D-22607 Germany
| | - Heshmat Noei
- Deutsches Elektronen Synchrotron (DESY), Hamburg, D-22607 Germany
| | - Vedran Vonk
- Deutsches Elektronen Synchrotron (DESY), Hamburg, D-22607 Germany
| | - Thomas Michely
- Institute of Physics II, University of Cologne, Cologne, D-50937 Germany
| | - Andreas Stierle
- Physics Department, University of Hamburg, Hamburg, D-20355 Germany
- Deutsches Elektronen Synchrotron (DESY), Hamburg, D-22607 Germany
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13
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Saha JK, Dutta A. A Review of Graphene: Material Synthesis from Biomass Sources. WASTE AND BIOMASS VALORIZATION 2021; 13:1385-1429. [PMID: 34548888 PMCID: PMC8446731 DOI: 10.1007/s12649-021-01577-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 09/08/2021] [Indexed: 05/30/2023]
Abstract
Single-atom-thick graphene is a particularly interesting material in basic research and applications owing to its remarkable electronic, mechanical, chemical, thermal, and optical properties. This leads to its potential use in a multitude of applications for improved energy storage (capacitors, batteries, and fuel cells), energy generation, biomedical, sensors or even as an advanced membrane material for separations. This paper provided an overview of research in graphene, in the area of synthesis from various sources specially from biomass, advanced characterization techniques, properties, and application. Finally, some challenges and future perspectives of graphene are also discussed.
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Affiliation(s)
| | - Animesh Dutta
- School of Engineering, University of Guelph, Guelph, Canada
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14
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Sorokin PB, Yakobson BI. Two-Dimensional Diamond-Diamane: Current State and Further Prospects. NANO LETTERS 2021; 21:5475-5484. [PMID: 34213910 DOI: 10.1021/acs.nanolett.1c01557] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional diamond, or diamane, is an ultrathin film with unique physical properties that combine the record values of the bulk crystal with the exciting features caused by the nanoscale nature. At the current stage of research, the diamane properties are mostly studied theoretically, and the main experimental efforts are directed at its synthesis. The latter is the trickiest problem since traditional methods involving the application of high pressure are not fully suitable due to the influence of surface effects. For diamane research, this poses a number of challenges, whose description is the main purpose and scope of this review. The paper also discusses the progress made so far and outlines the prospects for this field, at the crossroads of the timeless diamond and decade-old graphene.
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Affiliation(s)
- Pavel B Sorokin
- National University of Science and Technology MISiS, Moscow, 119049, Russian Federation
| | - Boris I Yakobson
- Department of Mechanical Engineering & Materials Science and the Smalley Institute for Nanoscale Science and Technology, Rice University, Houston, Texas 77005, United States
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15
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Grewal A, Wang Y, Münks M, Kern K, Ternes M. Local stiffness and work function variations of hexagonal boron nitride on Cu(111). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:559-565. [PMID: 34221802 PMCID: PMC8218540 DOI: 10.3762/bjnano.12.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/31/2021] [Indexed: 06/13/2023]
Abstract
Combined scanning tunnelling and atomic force microscopy using a qPlus sensor enables the measurement of electronic and mechanic properties of two-dimensional materials at the nanoscale. In this work, we study hexagonal boron nitride (h-BN), an atomically thin 2D layer, that is van der Waals-coupled to a Cu(111) surface. The system is of interest as a decoupling layer for functional 2D heterostructures due to the preservation of the h-BN bandgap and as a template for atomic and molecular adsorbates owing to its local electronic trapping potential due to the in-plane electric field. We obtain work function (Φ) variations on the h-BN/Cu(111) superstructure of the order of 100 meV using two independent methods, namely the shift of field emission resonances and the contact potential difference measured by Kelvin probe force microscopy. Using 3D force profiles of the same area we determine the relative stiffness of the Moiré region allowing us to analyse both electronic and mechanical properties of the 2D layer simultaneously. We obtain a sheet stiffness of 9.4 ± 0.9 N·m-1, which is one order of magnitude higher than the one obtained for h-BN/Rh(111). Using constant force maps we are able to derive height profiles of h-BN/Cu(111) showing that the system has a corrugation of 0.6 ± 0.2 Å, which helps to demystify the discussion around the flatness of the h-BN/Cu(111) substrate.
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Affiliation(s)
- Abhishek Grewal
- Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Yuqi Wang
- Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Matthias Münks
- Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
| | - Klaus Kern
- Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Institut de Physique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Markus Ternes
- Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
- Peter Grünberg Institute, Forschungszentrum Jülich, D-52425 Jülich, Germany
- II. Institute of Physics, RWTH Aachen University, D-52074 Aachen, Germany
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16
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Zhao Z, Wang Y, Wang C. A theoretical study of wrinkle propagation in graphene with flower-like grain boundaries. Phys Chem Chem Phys 2021; 23:11917-11930. [PMID: 33998625 DOI: 10.1039/d1cp01254a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study investigated dynamic surface wrinkle propagation across a series of flower-like rotational grain boundaries (GBs) in graphene using theoretical solutions and atomistic simulations. It was found that there was significantly less out-of-plane displacement of dynamic wrinkles when curvature of rotational GBs was reduced, which can be explained by a defect shielding effect of flower-like GBs. Potential energy evolved via different modes for pristine graphene and graphene with various GBs. With external excitation, the distinctly different patterns of wrinkle propagation in graphene with various GBs demonstrated how dynamic wrinkling can reveal defects. These results can provide a theoretical basis for guiding the design and implementation of graphene-based nano-mechanical devices such as protectors and detectors.
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Affiliation(s)
- Zihui Zhao
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150001, P. R. China. and Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Yafei Wang
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150001, P. R. China. and Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Changguo Wang
- National Key Laboratory of Science and Technology on Advanced Composites in Special Environments, Harbin Institute of Technology, Harbin 150001, P. R. China. and Center for Composite Materials and Structures, Harbin Institute of Technology, Harbin 150001, P. R. China
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17
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Liu Z, Hinaut A, Peeters S, Scherb S, Meyer E, Righi MC, Glatzel T. Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2021; 12:432-439. [PMID: 34104621 PMCID: PMC8144921 DOI: 10.3762/bjnano.12.35] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
A novel reconstruction of a two-dimensional layer of KBr on an Ir(111) surface is observed by high-resolution noncontact atomic force microscopy and verified by density functional theory (DFT). The observed KBr structure is oriented along the main directions of the Ir(111) surface, but forms a characteristic double-line pattern. Comprehensive calculations by DFT, taking into account the observed periodicities, resulted in a new low-energy reconstruction. However, it is fully relaxed into a common cubic structure when a monolayer of graphene is located between substrate and KBr. By using Kelvin probe force microscopy, the work functions of the reconstructed and the cubic configuration of KBr were measured and indicate, in accordance with the DFT calculations, a difference of nearly 900 meV. The difference is due to the strong interaction and local charge displacement of the K+/Br- ions and the Ir(111) surface, which are reduced by the decoupling effect of graphene, thus yielding different electrical and mechanical properties of the top KBr layer.
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Affiliation(s)
- Zhao Liu
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Antoine Hinaut
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Stefan Peeters
- Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy
| | - Sebastian Scherb
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Ernst Meyer
- Department of Physics, University of Basel, 4056 Basel, Switzerland
| | - Maria Clelia Righi
- Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy
| | - Thilo Glatzel
- Department of Physics, University of Basel, 4056 Basel, Switzerland
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18
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Esan DA, Trenary M. Interaction of CO with Pt nanoclusters on a graphene-covered Ru(0001) surface. J Chem Phys 2021; 154:114701. [PMID: 33752347 DOI: 10.1063/5.0042686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The adsorption of CO on Pt nanoclusters on a single layer of graphene epitaxially grown on the Ru(0001) surface [Gr/Ru(0001)] was studied with reflection absorption infrared spectroscopy (RAIRS) and temperature programmed desorption (TPD). The graphene layer was grown through exposure to ethylene using a method that has previously been shown to completely cover the surface. As CO adsorbs on Ru(0001) but not on graphene, the complete coverage of the Ru(0001) surface by graphene was verified with TPD as no CO adsorption was detectable. Previous work has demonstrated that Pt nanoclusters nucleate in the moiré unit cells of the Gr/Ru(0001) surface. Exposure of the Pt/Gr/Ru(0001) surface to CO gives rise to strong RAIRS peaks at 2065-2085 cm-1 assigned to CO at Pt atop sites and at 1848 cm-1 due to CO at Pt bridge sites. The CO TPD peak areas were used to quantify the CO coverage, which allowed for the determination of the RAIRS peak areas per CO molecule. It was found that the RAIRS intensity for CO on Pt/Gr/Ru(0001) is as much as nine times the intensity of CO on Ru(0001) on a per molecule basis. A more modest intensity enhancement was observed compared to CO on Pt islands on the Ru(0001) surface.
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Affiliation(s)
- Dominic A Esan
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60302, USA
| | - Michael Trenary
- Department of Chemistry, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60302, USA
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19
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Barreto L, Henrique de Lima L, Coutinho Martins D, Silva C, Cezar de Campos Ferreira R, Landers R, de Siervo A. Selecting 'convenient observers' to probe the atomic structure of CVD graphene on Ir(111) via photoelectron diffraction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:105001. [PMID: 33254156 DOI: 10.1088/1361-648x/abceff] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
CVD graphene grown on metallic substrates presents, in several cases, a long-range periodic structure due to a lattice mismatch between the graphene and the substrate. For instance, graphene grown on Ir(111), displays a corrugated supercell with distinct adsorption sites due to a variation of its local electronic structure. This type of surface reconstruction represents a challenging problem for a detailed atomic surface structure determination for experimental and theoretical techniques. In this work, we revisited the surface structure determination of graphene on Ir(111) by using the unique advantage of surface and chemical selectivity of synchrotron-based photoelectron diffraction. We take advantage of the Ir 4f photoemission surface state and use its diffraction signal as a probe to investigate the atomic arrangement of the graphene topping layer. We determine the average height and the overall corrugation of the graphene layer, which are respectively equal to 3.40 ± 0.11 Å and 0.45 ± 0.03 Å. Furthermore, we explore the graphene topography in the vicinity of its high-symmetry adsorption sites and show that the experimental data can be described by three reduced systems simplifying the moiré supercell multiple scattering analysis.
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Affiliation(s)
- Lucas Barreto
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, SP, Brazil
| | - Luis Henrique de Lima
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, SP, Brazil
| | - Daniel Coutinho Martins
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210-580, SP, Brazil
| | - Caio Silva
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas 13083-859, SP, Brazil
| | | | - Richard Landers
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas 13083-859, SP, Brazil
| | - Abner de Siervo
- Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, Campinas 13083-859, SP, Brazil
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20
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Hartl T, Will M, Čapeta D, Singh R, Scheinecker D, Boix de la Cruz V, Dellmann S, Lacovig P, Lizzit S, Senkovskiy BV, Grüneis A, Kralj M, Knudsen J, Kotakoski J, Michely T, Bampoulis P. Cluster Superlattice Membranes. ACS NANO 2020; 14:13629-13637. [PMID: 32910634 DOI: 10.1021/acsnano.0c05740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cluster superlattice membranes consist of a two-dimensional hexagonal lattice of similar-sized nanoclusters sandwiched between single-crystal graphene and an amorphous carbon matrix. The fabrication process involves three main steps, the templated self-organization of a metal cluster superlattice on epitaxial graphene on Ir(111), conformal embedding in an amorphous carbon matrix, and subsequent lift-off from the Ir(111) substrate. The mechanical stability provided by the carbon-graphene matrix makes the membrane stable as a free-standing material and enables transfer to other substrates. The fabrication procedure can be applied to a wide variety of cluster materials and cluster sizes from the single-atom limit to clusters of a few hundred atoms, as well as other two-dimensional layer/host matrix combinations. The versatility of the membrane composition, its mechanical stability, and the simplicity of the transfer procedure make cluster superlattice membranes a promising material in catalysis, magnetism, energy conversion, and optoelectronics.
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Affiliation(s)
- Tobias Hartl
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Moritz Will
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Davor Čapeta
- Institute of Physics, Bijenička cesta 46, 10000, Zagreb, Croatia
| | - Rajendra Singh
- Faculty of Physics, Vienna University, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Daniel Scheinecker
- Faculty of Physics, Vienna University, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Virginia Boix de la Cruz
- MAX IV Laboratory and Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden
| | - Sophia Dellmann
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Paolo Lacovig
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 Km 163.5, I-34149 Trieste, Italy
| | - Silvano Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 Km 163.5, I-34149 Trieste, Italy
| | - Boris V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Alexander Grüneis
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Marko Kralj
- Institute of Physics, Bijenička cesta 46, 10000, Zagreb, Croatia
| | - Jan Knudsen
- MAX IV Laboratory and Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden
| | - Jani Kotakoski
- Faculty of Physics, Vienna University, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
| | - Pantelis Bampoulis
- II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
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21
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Guo H, Martínez-Galera AJ, Gómez-Rodríguez JM. C 60 self-orientation on hexagonal boron nitride induced by intermolecular coupling. NANOTECHNOLOGY 2020; 32:025711. [PMID: 33073772 DOI: 10.1088/1361-6528/abbbb2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A deep grasp of the properties of the interface between organic molecules and hexagonal boron nitride (h-BN) is essential for the full implementation of these two building blocks in the next generation of electronic devices. Here, using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), we report on the geometric and electronic features of C60 evaporated on a single layer of h-BN grown on a Rh(110) surface under ultra-high vacuum. Two different molecular assemblies of C60 on the h-BN/Rh(110) surface were observed. The first STM study at room temperature (RT) and at low temperatures (40 K) looked at the molecular orientation of C60 on a two-dimensional layered material. Intramolecular-resolution images demonstrate the existence of a phase transition of C60 over the h-BN/Rh(110) surface similar to that found on bulk solid C60. At RT molecules exhibit random orientations, while at 40 K such rotational disorder vanishes and they adopt a common orientation over the h-BN/Rh(110) surface. The decrease in thermal energy allows recognition between C60 molecules, and they become equally oriented in the configuration at which the van der Waals intermolecular interactions are optimized. Bias-dependent submolecular features obtained by means of high-resolution STM images are interpreted as the highest occupied and lowest unoccupied molecular orbitals. STS data showed that fullerenes are electronically decoupled from the substrate, with a negligible charge transfer effect if any. Finally, the very early stages of multilayer growth were also investigated.
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Affiliation(s)
- Haojie Guo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Madrid E-28049, Spain
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22
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Klein J, Engstfeld AK, Brimaud S, Behm RJ. Pt nanocluster size effects in the hydrogen evolution reaction: approaching the theoretical maximum activity. Phys Chem Chem Phys 2020; 22:19059-19068. [PMID: 32812961 DOI: 10.1039/d0cp02793f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hydrogen production from electrocatalytic water splitting in electrolyzers is a key process to store excess electric energy produced from intermittent renewable energy sources. For proton exchange membrane (PEM) electrolyzers, carbon supported platinum particles exhibit the highest rates for the hydrogen evolution reaction (HER); however, high Pt costs limit the wide spread use of this technology. By employing a graphene layer grown on a Ru(0001) single crystal as a template for Pt nanocluster (NC) growth, we studied the dependence of the HER activity on the NC size using NCs of different sizes. We provide clear quantitative experimental evidence for a volcano-like relationship between the HER activity and the NC size which has been missing so far. For Pt NCs with very low sizes below 2 nm, we found stunningly improved exchange HER current densities. The highest exchange current density was observed for Pt NCs with an average size of ca. 38 atoms. These Pt38 NCs do not only surpass the Pt-mass-specific activity of commercial Pt electrode materials by well above three orders of magnitude, also their exchange current density is located close to the maximum exchange current density for the HER predicted theoretically for transition metal surfaces. The present work provides a strong stimulus for future research towards technically feasible Pt NC catalysts with cluster sizes in the range of few tens of Pt atoms.
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Affiliation(s)
- Jens Klein
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, D-89081 Ulm, Germany.
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23
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Zhang L, Dong J, Guan Z, Zhang X, Ding F. The alignment-dependent properties and applications of graphene moiré superstructures on the Ru(0001) surface. NANOSCALE 2020; 12:12831-12839. [PMID: 32515760 DOI: 10.1039/d0nr02370a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The moiré superstructure of graphene on a lattice-mismatched metal substrate has profound effects on the electronic properties of graphene and can be used for many applications. Here, we propose to systematically tune the moiré superstructure of graphene on the Ru(0001) surface by rotating the graphene layer. Our study reveals two kinds of graphene moiré superstructures: (i) the ultra-flat graphene layers with height variations of less than 0.1 Å for rotation angles greater than 20° that have the same structural and electronic properties everywhere, and (ii) the highly corrugated graphene moiré superstructures with height variations from 0.4 to 1.6 Å for rotation angles less than 20°, whose electronic properties are highly modulated by the interaction with the substrate. Moreover, these rotated graphene moiré superstructures can serve as templates to produce matrices of size-tunable metal clusters from a few to ∼100 atoms. This study reveals the causes of the structural fluctuation of moiré superstructures of graphene on the transition metal surface and suggests a pathway to tune graphene's electronic properties for various applications.
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Affiliation(s)
- Leining Zhang
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan 44919, Korea.
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24
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Jadoon T, Carter-Fenk K, Siddique MBA, Herbert JM, Hussain R, Iqbal S, Iqbal J, Ayub K. Silver clusters tune up electronic properties of graphene nanoflakes: A comprehensive theoretical study. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2019.111902] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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25
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Will M, Bampoulis P, Hartl T, Valerius P, Michely T. Conformal Embedding of Cluster Superlattices with Carbon. ACS APPLIED MATERIALS & INTERFACES 2019; 11:40524-40532. [PMID: 31588723 DOI: 10.1021/acsami.9b14616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Iridium cluster superlattices on the graphene moiré with Ir(111) are embedded with elemental carbon through vapor-phase deposition. Using scanning tunneling microscopy and spectroscopy, we find that carbon embedding is conformal and does not deteriorate the excellent order of the iridium clusters. The thermal and mechanical stability of the embedded clusters is greatly enhanced. Smoluchowski ripening as well as cluster pick-up by the scanning tunneling microscopy tip are both suppressed. The only cluster decay path left takes place at an elevated temperature of around 1050 K. The cluster material penetrates through the graphene sheet, whereby it becomes bound to the underlying metal. It is argued that conformal carbon embedding is an important step towards the formation of a new type of sintering-resistant cluster lattice material for nanocatalysis and nanomagnetism.
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Affiliation(s)
- Moritz Will
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Pantelis Bampoulis
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Tobias Hartl
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Philipp Valerius
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Thomas Michely
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
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26
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Di M, Fu L, Wang Y, Zhang K, Xu Y, Pan H, Du Y, Tang N. Electronic properties of α-graphyne on hexagonal boron nitride and α-BNyne substrates. RSC Adv 2019; 9:35297-35303. [PMID: 35530697 PMCID: PMC9074109 DOI: 10.1039/c9ra07869j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 10/24/2019] [Indexed: 11/21/2022] Open
Abstract
The upsurge in the research of α-graphyne (α-GY) has occurred due to the existence of a Dirac cone, whereas the absence of band gap impedes its semiconductor applications. Here, the electronic properties of α-GY on hexagonal boron nitride (h-BN) and α-BNyne (α-BNy) monolayers are investigated using first-principles calculations. Through engineering heterostructures, the band gap opening can be achieved and has different responses to the substrate and stacking sequence. Intriguingly, the band gap of α-GY/α-BNy with Ab1 stacking mode is up to 77.5 meV in the HSE06 functional, which is distinctly greater than K B T at room temperature. The characteristic Dirac band of α-GY is preserved on the α-BNy substrate, while it changes into a parabolic band on the h-BN substrate. Additionally, we also find that changing the interlayer distance is an alternative strategy to realize the tunable band gap. Our results show that by selecting a reasonable substrate, the linear band structure and thus the high carrier mobility as well as the distinct band gap opening could coexist in α-GY. These prominent properties are the key quantity for application of α-GY in nanoelectronic devices.
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Affiliation(s)
- Maoyun Di
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Lin Fu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Yong Wang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Kaiyu Zhang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Yongjie Xu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Hongzhe Pan
- School of Physics and Electronic Engineering, Linyi University Linyi 276005 China
| | - Youwei Du
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
| | - Nujiang Tang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University Nanjing 210093 China
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27
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Li J, Solianyk L, Schmidt N, Baker B, Gottardi S, Moreno Lopez JC, Enache M, Monjas L, van der Vlag R, Havenith RWA, Hirsch AKH, Stöhr M. Low-Dimensional Metal-Organic Coordination Structures on Graphene. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:12730-12735. [PMID: 31156737 PMCID: PMC6541427 DOI: 10.1021/acs.jpcc.9b00326] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 04/26/2019] [Indexed: 06/09/2023]
Abstract
We report the formation of one- and two-dimensional metal-organic coordination structures from para-hexaphenyl-dicarbonitrile (NC-Ph6-CN) molecules and Cu atoms on graphene epitaxially grown on Ir(111). By varying the stoichiometry between the NC-Ph6-CN molecules and Cu atoms, the dimensionality of the metal-organic coordination structures could be tuned: for a 3:2 ratio, a two-dimensional hexagonal porous network based on threefold Cu coordination was observed, while for a 1:1 ratio, one-dimensional chains based on twofold Cu coordination were formed. The formation of metal-ligand bonds was supported by imaging the Cu atoms within the metal-organic coordination structures with scanning tunneling microscopy. Scanning tunneling spectroscopy measurements demonstrated that the electronic properties of NC-Ph6-CN molecules and Cu atoms were different between the two-dimensional porous network and one-dimensional molecular chains.
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Affiliation(s)
- Jun Li
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Leonid Solianyk
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Nico Schmidt
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Brian Baker
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Stefano Gottardi
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Juan Carlos Moreno Lopez
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Faculty
of Physics, University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria
| | - Mihaela Enache
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Leticia Monjas
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Ramon van der Vlag
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Remco W. A. Havenith
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Ghent Quantum
Chemistry Group, University of Ghent, 9000 Ghent, Belgium
| | - Anna K. H. Hirsch
- Stratingh
Institute for Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
- Helmholtz
Institute
for Pharmaceutical Research Saarland (HIPS)—Helmholtz Centre
for Infection Research (HZI), Department of Drug Design and Optimization, Campus Building E8.1, 66123 Saarbrücken, Germany
- Department
of Pharmacy, Saarland University, Campus Building E8.1, 66123 Saarbrücken, Germany
| | - Meike Stöhr
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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28
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Capiod P, Bardotti L, Tamion A, Boisron O, Albin C, Dupuis V, Renaud G, Ohresser P, Tournus F. Elaboration of Nanomagnet Arrays: Organization and Magnetic Properties of Mass-Selected FePt Nanoparticles Deposited on Epitaxially Grown Graphene on Ir(111). PHYSICAL REVIEW LETTERS 2019; 122:106802. [PMID: 30932671 DOI: 10.1103/physrevlett.122.106802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 01/25/2019] [Indexed: 06/09/2023]
Abstract
The moiré pattern created by the epitaxy of a graphene sheet on an iridium substrate can be used as a template for the growth of 2D atomic or cluster arrays. We observed for the first time a coherent organization of hard magnetic preformed FePt nanoparticles on the 2D lattice of graphene on Ir(111). Nanoparticles of 2 nm diameter have been mass selected in a gas phase and deposited with low energy on the hexagonal moiré pattern. Their morphology and organization have been investigated using grazing incidence small angle x-ray scattering, while their magnetic properties have been studied by x-ray magnetic circular dichroism, both pointing to a FePt cluster-graphene surface specific interaction. The spatial coherence of the nanoparticles is preserved upon annealing up to 700 °C where the hard magnetic phase of FePt is obtained.
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Affiliation(s)
- Pierre Capiod
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Laurent Bardotti
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Alexandre Tamion
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Olivier Boisron
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Clément Albin
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Véronique Dupuis
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
| | - Gilles Renaud
- Université Grenoble Alpes, CEA, INAC, MEM, F-38000 Grenoble, France
| | - Philippe Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers, BP48, Saint-Aubin, 91192 Gif-sur-Yvette, France
| | - Florent Tournus
- Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex, France
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29
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Valerius P, Herman A, Michely T. Suppression of wrinkle formation in graphene on Ir(111) by high-temperature, low-energy ion irradiation. NANOTECHNOLOGY 2019; 30:085304. [PMID: 30523818 DOI: 10.1088/1361-6528/aaf534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Graphene on Ir(111) is irradiated with small fluences of 500 eV He ions at temperatures close to its chemical vapor deposition growth temperature. The ion irradiation experiments explore whether it is possible to suppress the formation of wrinkles in Gr during growth. It is found that the release of thermal mismatch strain by wrinkle formation can be entirely suppressed for an irradiation temperature of 880 °C. A model for the ion beam induced suppression of wrinkle formation in supported Gr is presented, and underpinned by experiments varying the irradiation temperature or involving intercalation subsequent to irradiation.
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30
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Martínez-Galera AJ, Gómez-Rodríguez JM. Pseudo-ordered distribution of Ir nanocrystals on h-BN. NANOSCALE 2019; 11:2317-2325. [PMID: 30662984 DOI: 10.1039/c8nr08928k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A 2D material consisting of a pseudo-ordered distribution of Ir nanocrystals supported on a h-BN/Rh(111) surface is presented here. The particular spatial distribution of the Ir nanoparticles is achieved thanks to the existence of a large variety of adsorption positions within the pores of the h-BN/Rh(111) nanomesh template with hexagonal symmetry. The resulting deviations of nanoparticle positions with respect to a perfect hexagonal lattice, which make this material of special interest in the field of optics, can be tuned by the temperature and the amount of Ir. Upon annealing, this material undergoes slight structural changes in the temperature range of 370-570 K and much more drastic ones, due to cluster coalescence, between 670 and 770 K. This relatively high onset of coalescence is encouraging for using this 2D material as a catalyst for reactions such as the oxidation of carbon monoxide or of nitrogen monoxide, which are especially relevant in the field of environmental science. Finally, metal nanostructures exhibiting regular geometries have been created from this material using a scanning tunneling microscope tip. Because of the insulating character of h-BN, these nanostructures could be very promising to use in the design of conductive nanotracks.
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Affiliation(s)
- Antonio J Martínez-Galera
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
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31
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Navarro JJ, Pisarra M, Nieto-Ortega B, Villalva J, Ayani CG, Díaz C, Calleja F, Miranda R, Martín F, Pérez EM, Vázquez de Parga AL. Graphene catalyzes the reversible formation of a C-C bond between two molecules. SCIENCE ADVANCES 2018; 4:eaau9366. [PMID: 30555920 PMCID: PMC6294602 DOI: 10.1126/sciadv.aau9366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C-C bond between -CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C-C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reaction.
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Affiliation(s)
- J. J. Navarro
- Dep. Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - M. Pisarra
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
- Dep. Química Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - B. Nieto-Ortega
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - J. Villalva
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - C. G. Ayani
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - C. Díaz
- Dep. Química Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- Institute for Advanced Research in Chemistry (IAdChem), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Cantoblanco, 28049 Madrid, Spain
| | - F. Calleja
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - R. Miranda
- Dep. Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Cantoblanco, 28049 Madrid, Spain
| | - F. Martín
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
- Dep. Química Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Cantoblanco, 28049 Madrid, Spain
| | - E. M. Pérez
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
| | - A. L. Vázquez de Parga
- Dep. Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, 28049 Madrid, Spain
- Condensed Matter Physics Center (IFIMAC), Cantoblanco, 28049 Madrid, Spain
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32
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Jochmann K, Bernhardt TM. The influence of metal cluster lattices on the screening of image potential state electrons on graphene. J Chem Phys 2018; 149:164706. [DOI: 10.1063/1.5052643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Kira Jochmann
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
| | - Thorsten M. Bernhardt
- Institute of Surface Chemistry and Catalysis, University of Ulm, Albert-Einstein-Allee 47, 89069 Ulm, Germany
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33
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Düll F, Schwaab V, Späth F, Bauer U, Bachmann P, Steinhauer J, Steinrück HP, Papp C. Sulfur oxidation on graphene-supported platinum nanocluster arrays. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.08.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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34
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Template Assisted Nucleation of Cobalt and Gold Nano-clusters on an Ultrathin Iron Oxide Film. Top Catal 2018. [DOI: 10.1007/s11244-018-0983-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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35
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Will M, Atodiresei N, Caciuc V, Valerius P, Herbig C, Michely T. A Monolayer of Hexagonal Boron Nitride on Ir(111) as a Template for Cluster Superlattices. ACS NANO 2018; 12:6871-6880. [PMID: 29920200 DOI: 10.1021/acsnano.8b02127] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The moiré of a monolayer of hexagonal boron nitride on Ir(111) is found to be a template for Ir, C, and Au cluster superlattices. Using scanning tunneling microscopy, the cluster structure and epitaxial relation to the substrate, the cluster binding site, the role of defects, as well as the thermal stability of the cluster lattice are investigated. The Ir and C cluster superlattices display a high thermal stability, before they decay by intercalation and Smoluchowski ripening. Ab initio calculations explain the extraordinarily strong Ir cluster binding through selective sp3 rehybridization of boron nitride involving B-Ir cluster bonds and a strengthening of the nitrogen bonds to the Ir substrate in a specific, initially only chemisorbed valley area within the moiré.
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Affiliation(s)
- Moritz Will
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Nicolae Atodiresei
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , Jülich D-52425 , Germany
| | - Vasile Caciuc
- Peter Grünberg Institut (PGI-1) and Institute for Advanced Simulation (IAS-1) , Forschungszentrum Jülich and JARA , Jülich D-52425 , Germany
| | - Philipp Valerius
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Charlotte Herbig
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
| | - Thomas Michely
- II. Physikalisches Institut , Universität zu Köln , Cologne D-50937 , Germany
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36
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Zhang Y, Zhang H, Cai Y, Song J, Qiao D, Chen Q, Hu F, Wang P, Huang K, He P. Calcium intercalation underneath N-layer graphene on 6H-SiC(0001). Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2018.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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37
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Valencia FJ, Hernandez-Vazquez EE, Bringa EM, Moran-Lopez JL, Rogan J, Gonzalez RI, Munoz F. Growth of Ni nanoclusters on irradiated graphene: a molecular dynamics study. Phys Chem Chem Phys 2018; 20:16347-16353. [PMID: 29683154 DOI: 10.1039/c7cp08642c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We studied the soft landing of Ni atoms on a previously damaged graphene sheet by means of molecular dynamics simulations. We found a monotonic decrease of the cluster frequency as a function of its size, but few big clusters comprise an appreciable fraction of the total number of Ni atoms. The aggregation of Ni atoms is also modeled by means of a simple phenomenological model. The results are in clear contrast with the case of hard or energetic landing of metal atoms, where there is a tendency to form mono-disperse metal clusters. This behavior is attributed to the high diffusion of unattached Ni atoms, together with vacancies acting as capture centers. The findings of this work show that a simple study of the energetics of the system is not enough in the soft landing regime, where it is unavoidable to also consider the growth process of metal clusters.
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Affiliation(s)
- F J Valencia
- Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
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38
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Metal Clusters Dispersed on Oxide Supports: Preparation Methods and Metal-Support Interactions. Top Catal 2018. [DOI: 10.1007/s11244-018-0957-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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39
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Presel F, Tetlow H, Bignardi L, Lacovig P, Tache CA, Lizzit S, Kantorovich L, Baraldi A. Graphene growth by molecular beam epitaxy: an interplay between desorption, diffusion and intercalation of elemental C species on islands. NANOSCALE 2018; 10:7396-7406. [PMID: 29616254 DOI: 10.1039/c8nr00615f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The growth of graphene by molecular beam epitaxy from an elemental carbon precursor is a very promising technique to overcome some of the main limitations of the chemical vapour deposition approach, such as the possibility to synthesize graphene directly on a wide variety of surfaces including semiconductors and insulators. However, while the individual steps of the chemical vapour deposition growth process have been extensively studied for several surfaces, such knowledge is still missing for the case of molecular beam epitaxy, even though it is a key ingredient to optimise its performance and effectiveness. In this work, we have performed a combined experimental and theoretical study comparing the growth rate of the molecular beam epitaxy and chemical vapour deposition processes on the prototypical Ir (111) surface. In particular, by employing high-resolution fast X-ray photoelectron spectroscopy, we were able to follow the growth of both single- and multi-layer graphene in real time, and to identify the spectroscopic fingerprints of the different C layers. Our experiments, supported by density functional theory calculations, highlight the role of the interaction between different C precursor species and the growing graphene flakes on the growth rate of graphene. These results provide an overview of the main differences between chemical vapour deposition and molecular beam epitaxy growth and thus on the main parameters which can be tuned to optimise growth conditions.
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Affiliation(s)
- Francesco Presel
- Physics Department, University of Trieste, Via Valerio 2, 34127 Trieste, Italy.
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40
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Abstract
Two-dimensional, graphene-based materials have attracted great attention as a new membrane building block, primarily owing to their potential to make the thinnest possible membranes and thus provide the highest permeance for effective sieving, assuming comparable porosity to conventional membranes and uniform molecular-sized pores. However, a great challenge exists to fabricate large-area, single-layered graphene or graphene oxide (GO) membranes that have negligible undesired transport pathways, such as grain boundaries, tears, and cracks. Therefore, model systems, such as a single flake or nanochannels between graphene or GO flakes, have been studied via both simulations and experiments to explore the transport mechanisms and separation potential of graphene-based membranes. This article critically reviews literature related to single- to few-layered graphene and GO membranes, from material synthesis and characteristics, fundamental membrane structures, and transport mechanisms to potential separation applications. Knowledge gaps between science and engineering in this new field and future opportunities for practical separation applications are also discussed.
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Affiliation(s)
- Fanglei Zhou
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA; ,
| | - Mahdi Fathizadeh
- Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA;
| | - Miao Yu
- Department of Chemical & Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA; ,
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41
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Buller O, Wang H, Wang W, Chi L, Heuer A. Boundary-induced nucleation control: a theoretical perspective. Phys Chem Chem Phys 2018; 20:3752-3760. [PMID: 29349464 DOI: 10.1039/c7cp02348k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pre-patterning of a substrate to create energetically more attractive or repulsive regions allows one to generate a variety of structures in physical vapor deposition experiments. A particularly interesting structure is generated if the energetically attractive region forms a rectangular grid. For specific combinations of the particle flux, the substrate temperature and the lattice size it is possible to generate exactly one cluster per cell, giving rise to nucleation control. Here, we show that the experimental observations of nucleation control can be very well understood from a theoretical perspective. For this purpose we perform, on the one hand, kinetic Monte Carlo simulations and, on the other hand, use analytical scaling arguments to rationalize the observed behavior. For several observables, characterizing nucleation control, very good agreement is found between experiment and theory. This underlines the generality of the presented mechanism to control the deposition of materials by manipulation of the direct environment.
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Affiliation(s)
- Oleg Buller
- Institute for Physical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster, Germany.
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42
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Soy E, Guisinger NP, Trenary M. Growth of Pd Nanoclusters on Single-Layer Graphene on Cu(111). J Phys Chem B 2018; 122:572-577. [PMID: 28678496 DOI: 10.1021/acs.jpcb.7b05064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report scanning tunneling microscopy results on the nucleation and growth of Pd nanoclusters on a single layer of graphene on the Cu(111) surface. The shape, organization, and structural evolution of the Pd nanoclusters were investigated using two different growth methods, continuous and stepwise. The size and shape of the formed nanoclusters were found to greatly depend on the growth technique used. The size and density of spherical Pd nanoclusters increased with increasing coverage during stepwise deposition as a result of coarsening of existing clusters and continued nucleation of new clusters. In contrast, continuous deposition gave rise to well-defined triangular Pd clusters as a result of anisotropic growth on the graphene surface. Exposure to ethylene caused a decrease in the size of the Pd clusters. This is attributed to the exothermic formation of ethylidyne on the cluster surfaces and an accompanying weakening of the Pd-Pd bonding.
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Affiliation(s)
- Esin Soy
- Department of Chemistry, University of Illinois at Chicago , 845 West Taylor Street, Chicago, Illinois 60607, United States
| | - Nathan P Guisinger
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Michael Trenary
- Department of Chemistry, University of Illinois at Chicago , 845 West Taylor Street, Chicago, Illinois 60607, United States
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43
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Qi Y, Meng C, Xu X, Deng B, Han N, Liu M, Hong M, Ning Y, Liu K, Zhao J, Fu Q, Li Y, Zhang Y, Liu Z. Unique Transformation from Graphene to Carbide on Re(0001) Induced by Strong Carbon–Metal Interaction. J Am Chem Soc 2017; 139:17574-17581. [DOI: 10.1021/jacs.7b09755] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yue Qi
- Center
for Nanochemistry (CNC), Academy for Advanced Interdisciplinary Studies,
Beijing National Laboratory for Molecular Sciences, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Caixia Meng
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
| | - Xiaozhi Xu
- State
Key Laboratory for Mesoscopic Physics, School of Physics, Academy
for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People’s Republic of China
| | - Bing Deng
- Center
for Nanochemistry (CNC), Academy for Advanced Interdisciplinary Studies,
Beijing National Laboratory for Molecular Sciences, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Nannan Han
- Key
Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People’ s Republic of China
| | - Mengxi Liu
- CAS
Key Laboratory of Standardization and Measurement for Nanotechnology,
CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People’s Republic of China
| | - Min Hong
- Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, People’s Republic of China
| | - Yanxiao Ning
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
| | - Kaihui Liu
- State
Key Laboratory for Mesoscopic Physics, School of Physics, Academy
for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, People’s Republic of China
| | - Jijun Zhao
- Key
Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People’ s Republic of China
| | - Qiang Fu
- State
Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116023, People’s Republic of China
| | - Yuanchang Li
- Advanced
Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China
| | - Yanfeng Zhang
- Center
for Nanochemistry (CNC), Academy for Advanced Interdisciplinary Studies,
Beijing National Laboratory for Molecular Sciences, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
- Department
of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, People’s Republic of China
- Beijing Graphene Institute (BGI), Beijing 100095, People’s Republic of China
| | - Zhongfan Liu
- Center
for Nanochemistry (CNC), Academy for Advanced Interdisciplinary Studies,
Beijing National Laboratory for Molecular Sciences, College of Chemistry
and Molecular Engineering, Peking University, Beijing 100871, People’s Republic of China
- Beijing Graphene Institute (BGI), Beijing 100095, People’s Republic of China
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Teshome T, Datta A. Two-Dimensional Graphene-Gold Interfaces Serve as Robust Templates for Dielectric Capacitors. ACS APPLIED MATERIALS & INTERFACES 2017; 9:34213-34220. [PMID: 28914055 DOI: 10.1021/acsami.7b09360] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electronic structures of novel heterostructures, namely, graphene-Au van der Waals (vdW) interfaces, have been studied using density functional theory. Dispersion-corrected PBE-D2 functionals are used to describe the phonon spectrum and binding energies. Ab initio molecular dynamics simulations reveal that the vdW framework is preserved till 1200 K. Beyond T = 1200 K, a transition of the quasiplanar Au into the three-dimensional cluster-like structure is observed. A dielectric capacitor is designed by placing 1-4 hexagonal boron nitride (h-BN) monolayers between graphene and Au conductive plates. Charge separation between the Au and graphene plates is carried out under the effect of an external field normal to the graphene-h-BN-Au interface. The gravimetric capacitances are computed as C1 = 7.6 μF/g and C2 = 3.2 μF/g for h-BN bilayers with the Au-graphene heterostructures. The capacitive behavior shows strong deviations from the classical charging models and exemplifies the importance of quantum phenomenon at short contacts, which eventually nullifies at large interelectrode distances. The graphene-Au interface is predicted to be an exciting vdW heterostructure with a potential application as a dielectric capacitor.
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Affiliation(s)
- Tamiru Teshome
- Department of Spectroscopy, Indian Association for the Cultivation of Science , 2A and 2B Raja S. C. Mullick Road, Jadavpur, 700032 Kolkata, West Bengal, India
| | - Ayan Datta
- Department of Spectroscopy, Indian Association for the Cultivation of Science , 2A and 2B Raja S. C. Mullick Road, Jadavpur, 700032 Kolkata, West Bengal, India
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Martínez-Galera AJ, Schröder UA, Herbig C, Arman MA, Knudsen J, Michely T. Preventing sintering of nanoclusters on graphene by radical adsorption. NANOSCALE 2017; 9:13618-13629. [PMID: 28876003 DOI: 10.1039/c7nr04491g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Metal nanoclusters, supported on inert substrates, exhibiting well-defined shapes and sizes in a broad range of temperatures are a major object of desire in nanotechnology. Here, a technique is presented that improves the thermal stability of monodisperse and crystalline transition metal nanoclusters grown in a regular array on metal-supported graphene. To stabilize the clusters after growth under ultrahigh vacuum the system composed of the aggregates and the graphene/metal interface is exposed to radicals resulting from the dissociation of diatomic gases. As a model system we have used Pt as the metal element for cluster growth and the template consisting of the moiré pattern resulting from the lattice mismatch between graphene and the Ir(111) surface. The study has been performed for deuterium and oxygen radicals, which interact very differently with graphene. Our results reveal that after radical exposure the thermally activated motion of Pt nanoclusters to adjacent moiré cells and the subsequent sintering of neighbor aggregates are avoided, most pronounced for the case of atomic O. For the case of D the limits of the improvement are given by radical desorption, whereas for the case of O they are defined by an interplay between coalescence and graphene etching followed by Pt intercalation, which can be controlled by the amount of exposure. Finally, we determined the mechanism of how radical adsorption improves the thermal stability of the aggregates.
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Affiliation(s)
- A J Martínez-Galera
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, D-50937 Köln, Germany.
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Tian T, Shih CJ. Molecular Epitaxy on Two-Dimensional Materials: The Interplay between Interactions. Ind Eng Chem Res 2017. [DOI: 10.1021/acs.iecr.7b02669] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tian Tian
- Institute for Chemical and
Bioengineering, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
| | - Chih-Jen Shih
- Institute for Chemical and
Bioengineering, ETH Zürich, Vladimir Prelog Weg 1, CH-8093 Zürich, Switzerland
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Kumar A, Banerjee K, Dvorak M, Schulz F, Harju A, Rinke P, Liljeroth P. Charge-Transfer-Driven Nonplanar Adsorption of F 4TCNQ Molecules on Epitaxial Graphene. ACS NANO 2017; 11:4960-4968. [PMID: 28467831 DOI: 10.1021/acsnano.7b01599] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
π-conjugated organic molecules tend to adsorb in a planar configuration on graphene irrespective of their charge state. In contrast, here we demonstrate charging-induced strong structural relaxation of tetrafluorotetracyanoquinodimethane (F4TCNQ) on epitaxial graphene on Ir(111) (G/Ir(111)). The work function modulation over the graphene moiré unit cell causes site-selective charging of F4TCNQ. Upon charging, the molecule anchors to the face-centered cubic sites of the G/Ir(111) moiré through one or two cyano groups. The reaction is reversible and can be triggered on a single molecule by moving it between different adsorption sites. We introduce a model taking into account the trade-off between tilt-induced charging and reduced van der Waals interactions, which provides a general framework for understanding charging-induced structural relaxation on weakly interacting substrates. In addition, we argue that the partial sp3 rehybridization of the underlying graphene and the possible bonding mechanism between the cyano groups and the graphene substrate are also relevant for the complete understanding of the experiments. These results provide insight into molecular charging on graphene, and they are directly relevant for potential device applications where the use of molecules has been suggested for doping and band structure engineering.
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Affiliation(s)
- Avijit Kumar
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Kaustuv Banerjee
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Marc Dvorak
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Fabian Schulz
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Ari Harju
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Patrick Rinke
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
| | - Peter Liljeroth
- Department of Applied Physics and ‡COMP/Department of Applied Physics, Aalto University School of Science , 00076 Aalto, Finland
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Herbig C, Knispel T, Simon S, Schröder UA, Martínez-Galera AJ, Arman MA, Teichert C, Knudsen J, Krasheninnikov AV, Michely T. From Permeation to Cluster Arrays: Graphene on Ir(111) Exposed to Carbon Vapor. NANO LETTERS 2017; 17:3105-3112. [PMID: 28426934 DOI: 10.1021/acs.nanolett.7b00550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Our scanning tunneling microscopy and X-ray photoelectron spectroscopy experiments along with first-principles calculations uncover the rich phenomenology and enable a coherent understanding of carbon vapor interaction with graphene on Ir(111). At high temperatures, carbon vapor not only permeates to the metal surface but also densifies the graphene cover. Thereby, in addition to underlayer graphene growth, upon cool down also severe wrinkling of the densified graphene cover is observed. In contrast, at low temperatures the adsorbed carbon largely remains on top and self-organizes into a regular array of fullerene-like, thermally highly stable clusters that are covalently bonded to the underlying graphene sheet. Thus, a new type of predominantly sp2-hybridized nanostructured and ultrathin carbon material emerges, which may be useful to encage or stably bind metal in finely dispersed form.
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Affiliation(s)
- Charlotte Herbig
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Timo Knispel
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Sabina Simon
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | - Ulrike A Schröder
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | | | | | - Christian Teichert
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
| | | | - Arkady V Krasheninnikov
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf , 01328 Dresden, Germany
- Department of Applied Physics, Aalto University School of Science , P.O. Box 11100, 00076 Aalto, Finland
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln , Zülpicher Straße 77, 50937 Köln, Germany
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Template Effect of the Graphene Moiré Lattice on Phthalocyanine Assembly. Molecules 2017; 22:molecules22050731. [PMID: 28467367 PMCID: PMC6154495 DOI: 10.3390/molecules22050731] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 11/17/2022] Open
Abstract
Superstructures of metal-free phthalocyanine (2H-Pc) molecules on graphene-covered Ir(111) have been explored by scanning tunnelling microscopy. Depending on the sub-monolayer coverage different molecular assemblies form at the surface. They reflect the transition from a graphene template effect on the 2H-Pc arrangement to molecular superstructures that are mainly governed by the intermolecular coupling.
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