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Nieman R, Aquino AJA, Lischka H. Exploration of Graphene Defect Reactivity toward a Hydrogen Radical Utilizing a Preactivated Circumcoronene Model. J Phys Chem A 2021; 125:1152-1165. [PMID: 33507752 DOI: 10.1021/acs.jpca.0c09255] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A preexisting chemisorbed defect is well-known to increase the reactivity of graphene which is normally chemically inert. Specifically, the presence of chemisorbed hydrogen atoms forming an sp3-hybridized C-H bond is known to increase the reactivity of neighboring carbon atoms toward additional hydrogenation with wide-ranging applications from materials science to astrochemistry. In this work, static DFT and DFT-based direct dynamics simulations are used to characterize the reactivity of a graphene sheet around an existing C-H bond defect. The spin density landscape shows how to guide subsequent H atom additions, always bonding most strongly to the carbon atom with greatest spin density. Molecular dynamics of an impinging H atom under thermal conditions with defect graphene was used to determine the statistics of probable reactions. The most frequent outcome is inelastic scattering (48%) and then Eley-Rideal (ER) abstraction of the chemisorbed H atom as vibrationally hot H2 (40%), while the least likely, but probably most interesting, result is formation of a novel C-H bond (12%). The C-H bonds always form in the β sublattice. The carbon atom in the para position shows to be most reactive toward the incoming H atom, followed by the ortho carbon, in agreement with the spin density computed in the static calculations. Globally, the graphene energy surface is repulsive, but the defects create local channels into this energy surface through which reactants can move locally through and react with the activated surface without a barrier.
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Affiliation(s)
- Reed Nieman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States.,Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Adelia J A Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States.,School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States.,School of Pharmaceutical Sciences and Technology, Tianjin University, Tianjin 300072, P. R. China
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2
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Deng K, Zhang M, Wu X, Zhang Q, Yang G, Ma Z, Wei F, Wang G, Liu W. Adsorption and Desorption of Tritium in Nuclear Graphite at 700°C: A Gas Chromatographic Study Using Hydrogen. NUCL TECHNOL 2019. [DOI: 10.1080/00295450.2019.1590076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Ke Deng
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Mingjun Zhang
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Xijun Wu
- University of South China, School of Math and Physics, Hengyang, Hunan, 421001, China
| | - Qin Zhang
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Guo Yang
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Zhaowei Ma
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Fei Wei
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
- University of Chinese Academy of Science, Beijing, 100049, China
| | - Guanghua Wang
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
| | - Wei Liu
- Chinese Academy of Science, Shanghai Institute of Applied Physics, Shanghai, 201800, China
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3
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Affiliation(s)
- Wei Fang
- School of Physics and Collaborative Innovation Centre of Quantum Matter, Peking University, Beijing, People's Republic of China
- Thomas Young Centre, London Centre for Nanotechnology, and Department of Physics and Astronomy, University College London, London, UK
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
| | - Ji Chen
- Department of Electronic Structure Theory, Max Plank Institute for Solid State Research, Stuttgart, Germany
| | - Yexin Feng
- School of Physics and Electronics, Hunan University, Changsha, People's Republic of China
| | - Xin-Zheng Li
- School of Physics and Collaborative Innovation Centre of Quantum Matter, Peking University, Beijing, People's Republic of China
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Peking University, Beijing, People's Republic of China
| | - Angelos Michaelides
- Thomas Young Centre, London Centre for Nanotechnology, and Department of Physics and Astronomy, University College London, London, UK
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4
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Lizzit D, Trioni MI, Bignardi L, Lacovig P, Lizzit S, Martinazzo R, Larciprete R. Dual-Route Hydrogenation of the Graphene/Ni Interface. ACS NANO 2019; 13:1828-1838. [PMID: 30633501 DOI: 10.1021/acsnano.8b07996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanostructured architectures based on graphene/metal interfaces might be efficiently exploited in hydrogen storage due to the attractive capability to provide adsorption sites both at the top side of graphene and at the metal substrate after intercalation. We combined in situ high-resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy with theoretical calculations to determine the arrangement of hydrogen atoms at the graphene/Ni(111) interface at room temperature. Our results show that at low coverage H atoms predominantly adsorb as monomers and that chemisorption saturates when ∼25% of the surface is hydrogenated. In parallel, with a much lower rate, H atoms intercalate below graphene and bind to Ni surface sites. Intercalation progressively destabilizes the C-H bonds and triggers the release of the hydrogen chemisorbed on graphene. Valence band and near-edge absorption spectroscopy demonstrate that the graphene layer is fully lifted when the Ni surface is saturated with H. Thermal programmed desorption was used to determine the stability of the hydrogenated interface. Whereas the H atoms chemisorbed on graphene remain unperturbed over a wide temperature range, the intercalated phase abruptly desorbs 50-100 K above room temperature.
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Affiliation(s)
- Daniel Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A. , AREA Science Park , S.S. 14 km 163.5, 34149 Trieste , Italy
| | - Mario I Trioni
- CNR-Institute of Molecular Science and Technologies (ISTM) , Via Golgi 19 , 20133 Milano , Italy
| | - Luca Bignardi
- Elettra-Sincrotrone Trieste S.C.p.A. , AREA Science Park , S.S. 14 km 163.5, 34149 Trieste , Italy
| | - Paolo Lacovig
- Elettra-Sincrotrone Trieste S.C.p.A. , AREA Science Park , S.S. 14 km 163.5, 34149 Trieste , Italy
| | - Silvano Lizzit
- Elettra-Sincrotrone Trieste S.C.p.A. , AREA Science Park , S.S. 14 km 163.5, 34149 Trieste , Italy
| | - Rocco Martinazzo
- Dipartimento di Chimica , Università degli Studi di Milano , Via Golgi 19 , 20133 Milano , Italy
| | - Rosanna Larciprete
- CNR-Institute for Complex Systems (ISC) , Via dei Taurini 19 , 00185 Roma , Italy
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5
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Bonfanti M, Achilli S, Martinazzo R. Sticking of atomic hydrogen on graphene. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:283002. [PMID: 29845971 DOI: 10.1088/1361-648x/aac89f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recent years have witnessed an ever growing interest in the interactions between hydrogen atoms and a graphene sheet. Largely motivated by the possibility of modulating the electric, optical and magnetic properties of graphene, a huge number of studies have appeared recently that added to and enlarged earlier investigations on graphite and other carbon materials. In this review we give a glimpse of the many facets of this adsorption process, as they emerged from these studies. The focus is on those issues that have been addressed in detail, under carefully controlled conditions, with an emphasis on the interplay between the adatom structures, their formation dynamics and the electric, magnetic and chemical properties of the carbon sheet.
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Affiliation(s)
- Matteo Bonfanti
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
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6
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Petucci J, Semone S, LeBlond C, Karimi M, Vidali G. Formation of H2 on graphene using Eley-Rideal and Langmuir-Hinshelwood processes. J Chem Phys 2018; 149:014702. [DOI: 10.1063/1.5026691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- J. Petucci
- Department of Physics and Astronomy, University of Denver, Denver, Colorado 80208, USA
| | - S. Semone
- Department of Physics, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705, USA
| | - C. LeBlond
- Department of Chemistry, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705, USA
| | - M. Karimi
- Department of Physics, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705, USA
| | - G. Vidali
- Department of Physics, Syracuse University, Syracuse, New York 13244, USA
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7
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Role of H Distribution on Coherent Quantum Transport of Electrons in Hydrogenated Graphene. CONDENSED MATTER 2017. [DOI: 10.3390/condmat2040037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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8
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Pham BQ, Gordon MS. Thermodynamics and kinetics of graphene chemistry: a graphene hydrogenation prototype study. Phys Chem Chem Phys 2016; 18:33274-33281. [PMID: 27896344 DOI: 10.1039/c6cp05687c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The thermodynamic and kinetic controls of graphene chemistry are studied computationally using a graphene hydrogenation reaction and polyaromatic hydrocarbons to represent the graphene surface. Hydrogen atoms are concertedly chemisorped onto the surface of graphene models of different shapes (i.e., all-zigzag, all-armchair, zigzag-armchair mixed edges) and sizes (i.e., from 16-42 carbon atoms). The second-order Z-averaged perturbation theory (ZAPT2) method combined with Pople double and triple zeta basis sets are used for all calculations. It is found that both the net enthalpy change and the barrier height of graphene hydrogenation at graphene edges are lower than at their interior surfaces. While the thermodynamic product distribution is mainly determined by the remaining π-islands of functionalized graphenes (Phys. Chem. Chem. Phys., 2013, 15, 3725-3735), the kinetics of the reaction is primarily correlated with the localization of the electrostatic potential of the graphene surface.
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Affiliation(s)
- Buu Q Pham
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
| | - Mark S Gordon
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
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9
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Casolo S, Tantardini GF, Martinazzo R. Hydrogen Recombination and Dimer Formation on Graphite from Ab Initio Molecular Dynamics Simulations. J Phys Chem A 2016; 120:5032-40. [DOI: 10.1021/acs.jpca.5b12761] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Casolo
- Dipartimento
di Chimica, Università degli Studi di Milano, via Golgi
19, 20133 Milan, Italy
| | - G. F. Tantardini
- Dipartimento
di Chimica, Università degli Studi di Milano, via Golgi
19, 20133 Milan, Italy
- Istituto di Scienze
e Tecnologie Molecolari, CNR-ISTM, via Golgi 19, 20133 Milan, Italy
| | - R. Martinazzo
- Dipartimento
di Chimica, Università degli Studi di Milano, via Golgi
19, 20133 Milan, Italy
- Istituto di Scienze
e Tecnologie Molecolari, CNR-ISTM, via Golgi 19, 20133 Milan, Italy
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10
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Pasquini M, Bonfanti M, Martinazzo R. Quantum dynamical investigation of the isotope effect in H2 formation on graphite at cold collision energies. Phys Chem Chem Phys 2016; 18:6607-17. [PMID: 26868899 DOI: 10.1039/c5cp07272g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Eley-Rideal abstraction of hydrogen atoms on graphitic surfaces at cold collision energies was investigated using a time-dependent wave packet method within the rigid-flat surface approximation, with a focus on hydrogen-deuterium isotopic substitutions. It is found that the marked isotope effect of collinear collisions disappears when the full dimensionality of the problem is taken into account, thereby suggesting that abstraction is less direct than commonly believed and proceeds through glancing rather than head-on collisions. In contrast, a clear isotope effect is observed for "hot-atom" formation, which appears to be strongly favored for heavy projectiles because of their higher density of physisorbed states. Overall, the dynamics is essentially classical and reasonably well described by quasi-classical trajectory methods at all but the lowest energies (≲10 meV). A comparison of the results obtained in the (substrate) adiabatic and diabatic limits suggests that the reaction is only marginally affected by the lattice dynamics, but highlights the importance of including energy dissipation processes in order to accurately describe the internal excitation of the product molecules.
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Affiliation(s)
- Marta Pasquini
- Universitá degli Studi di Milano, Dipartimento di Chimica, via Golgi 19, 20133 Milano, Italy.
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11
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Bonfanti M, Jackson B, Hughes KH, Burghardt I, Martinazzo R. Quantum dynamics of hydrogen atoms on graphene. II. Sticking. J Chem Phys 2015; 143:124704. [PMID: 26429029 DOI: 10.1063/1.4931117] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Following our recent system-bath modeling of the interaction between a hydrogen atom and a graphene surface [Bonfanti et al., J. Chem. Phys. 143, 124703 (2015)], we present the results of converged quantum scattering calculations on the activated sticking dynamics. The focus of this study is the collinear scattering on a surface at zero temperature, which is treated with high-dimensional wavepacket propagations with the multi-configuration time-dependent Hartree method. At low collision energies, barrier-crossing dominates the sticking and any projectile that overcomes the barrier gets trapped in the chemisorption well. However, at high collision energies, energy transfer to the surface is a limiting factor, and fast H atoms hardly dissipate their excess energy and stick on the surface. As a consequence, the sticking coefficient is maximum (∼0.65) at an energy which is about one and half larger than the barrier height. Comparison of the results with classical and quasi-classical calculations shows that quantum fluctuations of the lattice play a primary role in the dynamics. A simple impulsive model describing the collision of a classical projectile with a quantum surface is developed which reproduces the quantum results remarkably well for all but the lowest energies, thereby capturing the essential physics of the activated sticking dynamics investigated.
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Affiliation(s)
- Matteo Bonfanti
- Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano, Italy
| | - Bret Jackson
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Keith H Hughes
- School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW, United Kingdom
| | - Irene Burghardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt/Main, Germany
| | - Rocco Martinazzo
- Dipartimento di Chimica, Università degli Studi di Milano, v. Golgi 19, 20133 Milano, Italy
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12
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Lin C, Feng Y, Xiao Y, Dürr M, Huang X, Xu X, Zhao R, Wang E, Li XZ, Hu Z. Direct observation of ordered configurations of hydrogen adatoms on graphene. NANO LETTERS 2015; 15:903-908. [PMID: 25621539 DOI: 10.1021/nl503635x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ordered configurations of hydrogen adatoms on graphene have long been proposed, calculated, and searched for. Here, we report direct observation of several ordered configurations of H adatoms on graphene by scanning tunneling microscopy. On the top side of the graphene plane, H atoms in the configurations appear to stick to carbon atoms in the same sublattice. Scanning tunneling spectroscopy measurements revealed a substantial gap in the local density of states in H-contained regions as well as in-gap states below the conduction band due to the incompleteness of H ordering. These findings can be well explained by density functional theory calculations based on double-sided H configurations. In addition, factors that may influence H ordering are discussed.
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Affiliation(s)
- Chenfang Lin
- State Key Lab for Mesoscopic Physics, School of Physics, Peking University , Beijing 100871, China
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13
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Davidson ERM, Klimeš J, Alfè D, Michaelides A. Cooperative interplay of van der Waals forces and quantum nuclear effects on adsorption: H at graphene and at coronene. ACS NANO 2014; 8:9905-9913. [PMID: 25300825 DOI: 10.1021/nn505578x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The energetic barriers that atoms and molecules often experience when binding to surfaces are incredibly important to a myriad of chemical and physical processes. However, these barriers are difficult to describe accurately with current computer simulation approaches. Two prominent contemporary challenges faced by simulation are the role of van der Waals forces and nuclear quantum effects. Here we examine the widely studied model systems of hydrogen on graphene and coronene using a van der Waals inclusive density functional theory approach together with path integral molecular dynamics at 50 K. We find that both van der Waals and quantum nuclear effects work together in a cooperative manner to dramatically reduce the barriers for hydrogen atoms to adsorb. This suggests that the low temperature hydrogenation of graphene is easier than previously thought and in more general terms that the combined roles of van der Waals and quantum tunnelling can lead to qualitative changes in adsorption.
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Affiliation(s)
- Erlend R M Davidson
- London Centre for Nanotechnology, University College London , London WC1E 6BT, U.K
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14
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Cortés-Arriagada D, Gutiérrez-Oliva S, Herrera B, Soto K, Toro-Labbé A. The mechanism of chemisorption of hydrogen atom on graphene: Insights from the reaction force and reaction electronic flux. J Chem Phys 2014; 141:134701. [DOI: 10.1063/1.4896611] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Petucci J, LeBlond C, Karimi M, Vidali G. Diffusion, adsorption, and desorption of molecular hydrogen on graphene and in graphite. J Chem Phys 2014; 139:044706. [PMID: 23902002 DOI: 10.1063/1.4813919] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The diffusion of molecular hydrogen (H2) on a layer of graphene and in the interlayer space between the layers of graphite is studied using molecular dynamics computer simulations. The interatomic interactions were modeled by an Adaptive Intermolecular Reactive Empirical Bond Order (AIREBO) potential. Molecular statics calculations of H2 on graphene indicate binding energies ranging from 41 meV to 54 meV and migration barriers ranging from 3 meV to 12 meV. The potential energy surface of an H2 molecule on graphene, with the full relaxations of molecular hydrogen and carbon atoms is calculated. Barriers for the formation of H2 through the Langmuir-Hinshelwood mechanism are calculated. Molecular dynamics calculations of mean square displacements and average surface lifetimes of H2 on graphene at various temperatures indicate a diffusion barrier of 9.8 meV and a desorption barrier of 28.7 meV. Similar calculations for the diffusion of H2 in the interlayer space between the graphite sheets indicate high and low temperature regimes for the diffusion with barriers of 51.2 meV and 11.5 meV. Our results are compared with those of first principles.
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Affiliation(s)
- Justin Petucci
- Department of Physics, Indiana University of Pennsylvania, Indiana, Pennsylvania 15705, USA
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16
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Herbst E. Three milieux for interstellar chemistry: gas, dust, and ice. Phys Chem Chem Phys 2014; 16:3344-59. [DOI: 10.1039/c3cp54065k] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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17
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Affiliation(s)
- Gianfranco Vidali
- Syracuse University , 201 Physics Building, Syracuse, New York 13244, United States
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18
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Insights into H2 formation in space from ab initio molecular dynamics. Proc Natl Acad Sci U S A 2013; 110:6674-7. [PMID: 23572584 DOI: 10.1073/pnas.1301433110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hydrogen formation is a key process for the physics and the chemistry of interstellar clouds. Molecular hydrogen is believed to form on the carbonaceous surface of dust grains, and several mechanisms have been invoked to explain its abundance in different regions of space, from cold interstellar clouds to warm photon-dominated regions. Here, we investigate direct (Eley-Rideal) recombination including lattice dynamics, surface corrugation, and competing H-dimers formation by means of ab initio molecular dynamics. We find that Eley-Rideal reaction dominates at energies relevant for the interstellar medium and alone may explain observations if the possibility of facile sticking at special sites (edges, point defects, etc.) on the surface of the dust grains is taken into account.
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Mandeltort L, Choudhury P, Johnson JK, Yates JT. Reaction of the Basal Plane of Graphite with the Methyl Radical. J Phys Chem Lett 2012; 3:1680-1683. [PMID: 26285728 DOI: 10.1021/jz300578x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The reaction of methyl radicals with the basal plane of graphite has been observed to occur with an activation energy of less than 0.3 eV. This reaction is initiated by Li-induced CH3Cl dissociation to produce CH3 radicals on the graphite surface. It is found that ∼3/4 of the methyl radicals remain on the graphite surface up to 700 K at puckered sp(3) carbon sites, while 1/4 of the CH3 radicals participate in CH4 formation and small amounts of C2 and C3 hydrocarbon formation. CH3 radicals become mobile over an activation energy barrier of ∼0.7 eV.
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Affiliation(s)
- Lynn Mandeltort
- †Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
| | - Pabitra Choudhury
- ‡Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - J Karl Johnson
- ‡Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
- §National Energy Technology Laboratory, Pittsburgh, Pennsylvania 15236, United States
| | - John T Yates
- †Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904, United States
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20
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Rougeau N, Teillet-Billy D, Sidis V. On the PES for the interaction of an H atom with an H chemisorbate on a graphenic platelet. Phys Chem Chem Phys 2011; 13:17579-87. [PMID: 21892489 DOI: 10.1039/c1cp22202c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motivated by the problem of H(2) formation in diffuse clouds of the interstellar medium (ISM), we study the effect of including van der Waals-type corrections in DFT calculations on the entrance PES of the Eley-Rideal reaction H(b) + H(a)-GR → H(b)-H(a) + GR for a graphenic surface GR. The present calculations make use of the PBE-D3 dispersion corrected functional of Grimme et al. (2010) and are carried out on cluster models of graphenic surfaces: C(24)H(12) and C(54)H(18). To assess the soundness of the chosen functional we start by revisiting the H-GR adsorption potential. We find a satisfactory on top physisorption well (43-48 meV) correctly located at an H-GR distance of 3 Å. We then revisit the H(b)-H(a)-GR system using both the PW91 and PBE functionals. Our calculations do not reproduce the tiny potential barrier reported earlier for large H(b)distances from the surface. The barrier in the calculations of Sidis et al. (2000) and Morisset et al. (2003, 2004) has been traced to their previous use of an LSDA + POSTSCF PW91 procedure rather than the genuine PW91 one. The new PBE-D3 PES for the H(b)-H(a)-GR system is reported as a function of the H(b) distance to the surface and its impact parameter relative to the H(a) chemisorbate for the so-called "fixed puckered" ("diabatic" or "sudden") approach. The results are discussed in relation to recent experimental and theoretical work.
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Affiliation(s)
- N Rougeau
- Institut des Sciences Moléculaires d'Orsay, CNRS - Univ. Paris-Sud 11, F91405 Orsay Cedex, France.
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21
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Huang LF, Ni MY, Zhang GR, Zhou WH, Li YG, Zheng XH, Zeng Z. Modulation of the thermodynamic, kinetic, and magnetic properties of the hydrogen monomer on graphene by charge doping. J Chem Phys 2011; 135:064705. [DOI: 10.1063/1.3624657] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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