1
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Gerrits N, Jackson B, Bogaerts A. Accurate Reaction Probabilities for Translational Energies on Both Sides of the Barrier of Dissociative Chemisorption on Metal Surfaces. J Phys Chem Lett 2024; 15:2566-2572. [PMID: 38416779 PMCID: PMC10926167 DOI: 10.1021/acs.jpclett.3c03408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/16/2024] [Accepted: 02/26/2024] [Indexed: 03/01/2024]
Abstract
Molecular dynamics simulations are essential for a better understanding of dissociative chemisorption on metal surfaces, which is often the rate-controlling step in heterogeneous and plasma catalysis. The workhorse quasi-classical trajectory approach ubiquitous in molecular dynamics is able to accurately predict reactivity only for high translational and low vibrational energies. In contrast, catalytically relevant conditions generally involve low translational and elevated vibrational energies. Existing quantum dynamics approaches are intractable or approximate as a result of the large number of degrees of freedom present in molecule-metal surface reactions. Here, we extend a ring polymer molecular dynamics approach to fully include, for the first time, the degrees of freedom of a moving metal surface. With this approach, experimental sticking probabilities for the dissociative chemisorption of methane on Pt(111) are reproduced for a large range of translational and vibrational energies by including nuclear quantum effects and employing full-dimensional simulations.
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Affiliation(s)
- Nick Gerrits
- Leiden
Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Post Office
Box 9502, 2300 RA Leiden, Netherlands
- Research
Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, BE-2610, Wilrijk, Antwerp, Belgium
| | - Bret Jackson
- Department
of Chemistry, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Annemie Bogaerts
- Research
Group PLASMANT, Department of Chemistry, University of Antwerp, Universiteitsplein 1, BE-2610, Wilrijk, Antwerp, Belgium
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2
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Kumar A, Singh SK, Shirhatti PR. A versatile and narrow linewidth infrared radiation source for ro-vibration state-selected preparation of molecules in molecular beams. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:113001. [PMID: 37947498 DOI: 10.1063/5.0157912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 10/09/2023] [Indexed: 11/12/2023]
Abstract
We describe the design and characterization of a versatile pulsed (5 ns, 10 Hz repetition rate) optical parametric oscillator and amplifier system capable of generating single longitudinal mode, narrow linewidth (0.01 cm-1) radiations in the wavelength range of 680-870 nm and 1380-4650 nm. Using a combination of power-normalized photoacoustic signal and a Fizeau interferometer-based wavemeter, we are able to actively stabilize the output wavenumber to within 0.005 cm-1 (3σ) over a timescale longer than 1000 s. We demonstrate an application of this system by performing ro-vibration state-selected preparation of CO in the v = 2 state, via direct overtone excitation (v = 0 → 2 at 2346 nm) and subsequent state-selected detection in an internally cold molecular beam.
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Affiliation(s)
- Avinash Kumar
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally, Hyderabad 500046, Telangana, India
| | - Saurabh Kumar Singh
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally, Hyderabad 500046, Telangana, India
| | - Pranav R Shirhatti
- Tata Institute of Fundamental Research Hyderabad, 36/P Gopanpally, Hyderabad 500046, Telangana, India
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3
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Roy S, Tiwari A. Mode Selective Chemistry for the Dissociation of Methane on Efficient Ni/Pt-Bimetallic Alloy Catalysts. Phys Chem Chem Phys 2022; 24:16596-16610. [DOI: 10.1039/d2cp02030k] [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 mode selectivity of methane dissociation is studied on three different Ni/Pt-bimetallic alloy surfaces using a fully quantum approach based on reaction path Hamiltonian. Dissociative sticking probability depends on the...
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4
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Ren Y, Liu X, Zhang Z, Shen X. Methane activation on single-atom Ir-doped metal nanoparticles from first principles. Phys Chem Chem Phys 2021; 23:15564-15573. [PMID: 34259268 DOI: 10.1039/d1cp02022f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The breaking of the C-H bond of CH4 is of great importance, and one of the most efficient strategies in heterogeneous catalysis is to alter the electronic structure of a surface by doping it with different metal elements or controlling the stoichiometry. We present an in-depth study on methane activation on pure metal and single-atom Ir-doped alloy nanoparticles, which are constructed based on (100), (110), (111) surfaces using density functional theory (DFT) calculations. DFT results show that the dissociation barriers of CH4 on the Ir-doped alloy surfaces are about 0.3-0.4 eV, much lower than those on the pure metal surfaces (i.e., 0.6-0.8 eV). DFT-based transition state theory further reveals the rates of the first C-H activation on single-atom Ir-doped alloy nanoparticles at the early stages. Importantly, a strong temperature dependence is mainly contributed by the proportion of the exposed (110) surface. The Ir-doped Pt nanoparticle is found to be an efficient catalyst for methane activation in potential industrial applications. These important results are helpful for further designing new metal catalysts for methane activation at the atomic/molecular level.
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Affiliation(s)
- Yugang Ren
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, Zhengzhou University, Zhengzhou 450001, China.
| | - Xiaojing Liu
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, Zhengzhou University, Zhengzhou 450001, China.
| | - Zhaojun Zhang
- State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China
| | - Xiangjian Shen
- Engineering Research Center of Advanced Functional Material Manufacturing of Ministry of Education, Zhengzhou University, Zhengzhou 450001, China.
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5
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Roy S, K. J. N, Tiwari N, Tiwari AK. Energetics and dynamics of CH4 and H2O dissociation on metal surfaces. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1765598] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Sudipta Roy
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Nayanthara K. J.
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Nidhi Tiwari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Ashwani K. Tiwari
- Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
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6
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Maitre PA, Bieniek MS, Kechagiopoulos PN. Plasma-enhanced catalysis for the upgrading of methane: a review of modelling and simulation methods. REACT CHEM ENG 2020. [DOI: 10.1039/d0re00024h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Modelling methods and simulation works on the upgrading of methane via plasma and plasma-enhanced catalysis reviewed.
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Affiliation(s)
- Pierre-André Maitre
- Chemical and Materials Engineering Group
- School of Engineering
- University of Aberdeen
- Aberdeen
- UK
| | - Matthew S. Bieniek
- Chemical and Materials Engineering Group
- School of Engineering
- University of Aberdeen
- Aberdeen
- UK
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7
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Gerrits N, Chadwick H, Kroes GJ. Dynamical Study of the Dissociative Chemisorption of CHD 3 on Pd(111). THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:24013-24023. [PMID: 31602282 PMCID: PMC6778984 DOI: 10.1021/acs.jpcc.9b05757] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 08/20/2019] [Indexed: 06/10/2023]
Abstract
The specific reaction parameter (SRP) approach to density functional theory has been shown to model reactions of polyatomic molecules with metal surfaces important for heterogeneous catalysis in the industry with chemical accuracy. However, transferability of the SRP functional among systems in which methane interacts with group 10 metals remains unclear for methane + Pd(111). Therefore, in this work, predictions have been made for the reaction of CHD3 on Pd(111) using Born-Oppenheimer molecular dynamics while also performing a rough comparison with experimental data for CH4 + Pd(111) obtained for lower incidence energies. Hopefully, future experiments can test the transferability of the SRP functional among group 10 metals also for Pd(111). We found that the reactivity of CHD3 on Pd(111) is intermediate between and similar to either Pt(111) or Ni(111), depending on the incidence energy and the initial vibrational state distribution. This is surprising because the barrier height and experiments performed at lower incidence energies than investigated here suggest that the reactivity of Pd(111) should be similar to that of Pt(111) only. The relative decrease in the reactivity of Pd(111) at high incidence energies is attributed to site specificity of the reaction and to dynamical effects such as the bobsled effect and energy transfer from methane to the surface.
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Affiliation(s)
- Nick Gerrits
- Gorlaeus
Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, the Netherlands
| | - Helen Chadwick
- Department
of Chemistry, Swansea University, Singleton Park, Swansea SA2 8PP, U.K.
| | - Geert-Jan Kroes
- Gorlaeus
Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, the Netherlands
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8
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Jiang B, Guo H. Dynamics in reactions on metal surfaces: A theoretical perspective. J Chem Phys 2019; 150:180901. [PMID: 31091904 DOI: 10.1063/1.5096869] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent advances in theoretical characterization of reaction dynamics on metal surfaces are reviewed. It is shown that the widely available density functional theory of metals and their interactions with molecules have enabled first principles theoretical models for treating surface reaction dynamics. The new theoretical tools include methods to construct high-dimensional adiabatic potential energy surfaces, to characterize nonadiabatic processes within the electronic friction models, and to describe dynamics both quantum mechanically and classically. Three prototypical surface reactions, namely, dissociative chemisorption, Eley-Rideal reactions, and recombinative desorption, are surveyed with a focus on some representative examples. While principles governing gas phase reaction dynamics may still be applicable, the presence of the surface introduces a higher level of complexity due to strong interaction between the molecular species and metal substrate. Furthermore, most of these reactive processes are impacted by energy exchange with surface phonons and/or electron-hole pair excitations. These theoretical studies help to interpret and rationalize experimental observations and, in some cases, guide experimental explorations. Knowledge acquired in these fundamental studies is expected to impact many practical problems in a wide range of interfacial processes.
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Affiliation(s)
- Bin Jiang
- Hefei National Laboratory for Physical Science at the Microscale, Department of Chemical Physics, Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei 230026, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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9
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Kondo T, Al Taleb A, Anemone G, Farías D. Low-energy methane scattering from Pt(111). J Chem Phys 2018; 149:084703. [PMID: 30193506 DOI: 10.1063/1.5044744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We have measured the temperature dependence of angular distributions of CH4 from Pt(111) at an incident energy of 109 meV. A broad angular distribution has been observed along the two main symmetry directions, whereby the peak center shifts from the supra-specular position to the sub-specular position when the surface temperature increases from 120 K to 800 K. Different widths have been measured for the scattering patterns along the [ 1¯01 ] and the [ 2¯11 ] azimuthal directions. Based on calculations performed within the binary collision model, these differences have been ascribed to different corrugations of the CH4-Pt(111) interaction potential along the two high-symmetry directions. This corrugation has been estimated from the model calculations to amount ∼0.03 Å, a factor of three larger than the one measured with helium diffraction.
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Affiliation(s)
- Takahiro Kondo
- Department of Materials Science and Tsukuba Research Center for Energy Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
| | - Amjad Al Taleb
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Gloria Anemone
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Daniel Farías
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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10
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Observation of the adsorption and desorption of vibrationally excited molecules on a metal surface. Nat Chem 2018; 10:592-598. [DOI: 10.1038/s41557-018-0003-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 12/21/2017] [Indexed: 11/08/2022]
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11
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German ED. Theoretical models of X–H bonds breaking (X = C, O, and H) over metal surfaces: Used for simulation of catalytic methane steam reforming. RUSS J ELECTROCHEM+ 2017. [DOI: 10.1134/s1023193517100044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Al Taleb A, Farías D. Coherent quantum scattering of CH 4 from Ni(111). Phys Chem Chem Phys 2017; 19:21267-21271. [PMID: 28762404 DOI: 10.1039/c7cp04559j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have measured high-resolution angular distributions of methane scattered from a Ni(111) surface at incident energies between 68.9 meV and 108.6 meV. A sharp and intense specular peak has been observed, in addition to sharp features corresponding to rotationally inelastic diffraction (RID) peaks along the two main symmetry directions of Ni(111). The intensity of the most intense RID peaks is ca. 50% of the specular one. The observation of sharp, coherent elastic peaks at such low incident energies suggests that single scattering dominates over trapping at these energies, and that the depth of the van der Waals well should be lower than 60 meV. In contrast, a broad angular distribution shifted from the specular position is observed from a graphene-covered Ni(111) surface under identical incident conditions. These results open up the possibility of studying the physisorption well between CH4 and a transition metal surface using high-resolution molecular beams.
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Affiliation(s)
- Amjad Al Taleb
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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13
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Affiliation(s)
- Helen Chadwick
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland;,
| | - Rainer D. Beck
- Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland;,
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14
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Guo H, Jackson B. Mode-selective chemistry on metal surfaces: The dissociative chemisorption of CH4 on Pt(111). J Chem Phys 2016; 144:184709. [DOI: 10.1063/1.4948941] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Han Guo
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | - Bret Jackson
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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15
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Nattino F, Migliorini D, Bonfanti M, Kroes GJ. Methane dissociation on Pt(111): Searching for a specific reaction parameter density functional. J Chem Phys 2016; 144:044702. [DOI: 10.1063/1.4939520] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Francesco Nattino
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Davide Migliorini
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Matteo Bonfanti
- Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano, Italy
| | - Geert-Jan Kroes
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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16
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Jiang B, Yang M, Xie D, Guo H. Quantum dynamics of polyatomic dissociative chemisorption on transition metal surfaces: mode specificity and bond selectivity. Chem Soc Rev 2016; 45:3621-40. [DOI: 10.1039/c5cs00360a] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent advances in quantum dynamical characterization of polyatomic dissociative chemisorption on accurate global potential energy surfaces are critically reviewed.
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Affiliation(s)
- Bin Jiang
- Department of Chemistry and Chemical Biology
- University of New Mexico
- Albuquerque
- USA
- Department of Chemical Physics
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics
- Wuhan Centre for Magnetic Resonance
- Wuhan Institute of Physics and Mathematics
- Chinese Academy of Sciences
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry
- Key Laboratory of Mesoscopic Chemistry
- School of Chemistry and Chemical Engineering
- Nanjing University
- Nanjing 210093
| | - Hua Guo
- Department of Chemistry and Chemical Biology
- University of New Mexico
- Albuquerque
- USA
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17
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Nave S, Tiwari AK, Jackson B. Dissociative Chemisorption of Methane on Ni and Pt Surfaces: Mode-Specific Chemistry and the Effects of Lattice Motion. J Phys Chem A 2014; 118:9615-31. [DOI: 10.1021/jp5063644] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sven Nave
- Institut des Sciences
Moléculaires d’Orsay, Université Paris-Sud 11/CNRS-UMR
8214, Université Paris-Sud, Bât. 351, 91405 Orsay Cedex, France
| | - Ashwani K. Tiwari
- Indian Institute of Science Education and Research Kolkata, Mohanpur 741252, India
| | - Bret Jackson
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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18
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Nattino F, Ueta H, Chadwick H, van Reijzen ME, Beck RD, Jackson B, van Hemert MC, Kroes GJ. Ab Initio Molecular Dynamics Calculations versus Quantum-State-Resolved Experiments on CHD3 + Pt(111): New Insights into a Prototypical Gas-Surface Reaction. J Phys Chem Lett 2014; 5:1294-1299. [PMID: 26269970 DOI: 10.1021/jz500233n] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The dissociative chemisorption of methane on metal surfaces is of fundamental and practical interest, being a rate-limiting step in the steam reforming process. The reaction is best modeled with quantum dynamics calculations, but these are currently not guaranteed to produce accurate results because they rely on potential energy surfaces based on untested density functionals and on untested dynamical approximations. To help overcome these limitations, here we present for the first time statistically accurate reaction probabilities obtained with ab initio molecular dynamics (AIMD) for a polyatomic gas-phase molecule reacting with a metal surface. Using a general purpose density functional, the AIMD reaction probabilities are in semiquantitative agreement with new quantum-state-resolved experiments on CHD3 + Pt(111). The comparison suggests the use of the sudden approximation for treating the rotations even though CHD3 has large rotational constants and yields an estimated reaction barrier of 0.9 eV for CH4 + Pt(111).
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Affiliation(s)
- Francesco Nattino
- †Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Hirokazu Ueta
- ‡Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Helen Chadwick
- ‡Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Maarten E van Reijzen
- ‡Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Rainer D Beck
- ‡Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Bret Jackson
- §Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Marc C van Hemert
- †Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Geert-Jan Kroes
- †Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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19
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Jiang B, Guo H. Mode and Bond Selectivities in Methane Dissociative Chemisorption: Quasi-Classical Trajectory Studies on Twelve-Dimensional Potential Energy Surface. THE JOURNAL OF PHYSICAL CHEMISTRY C 2013; 117:16127-16135. [DOI: 10.1021/jp405720c] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Affiliation(s)
- Bin Jiang
- Department of Chemistry and Chemical Biology, University
of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University
of New Mexico, Albuquerque, New Mexico 87131, United States
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20
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Chen N, Huang Y, Utz AL. State-Resolved Reactivity of Methane (ν2 + ν4) on Ni(111). J Phys Chem A 2013; 117:6250-5. [DOI: 10.1021/jp400571v] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nan Chen
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts
02155, United States
| | - Yongli Huang
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts
02155, United States
| | - Arthur L. Utz
- Department of Chemistry, Tufts University, 62 Talbot Avenue, Medford, Massachusetts
02155, United States
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21
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Monge-Palacios M, Espinosa-Garcia J. Role of Vibrational and Translational Energy in the OH + NH3 Reaction: A Quasi-Classical Trajectory Study. J Phys Chem A 2013; 117:5042-51. [DOI: 10.1021/jp403571y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Monge-Palacios
- Departamento de Química
Física, Universidad de Extremadura, 06071 Badajoz, Spain
| | - J. Espinosa-Garcia
- Departamento de Química
Física, Universidad de Extremadura, 06071 Badajoz, Spain
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22
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Jackson B, Nave S. The dissociative chemisorption of methane on Ni(111): The effects of molecular vibration and lattice motion. J Chem Phys 2013; 138:174705. [DOI: 10.1063/1.4802008] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Jiang B, Li J, Xie D, Guo H. Effects of reactant internal excitation and orientation on dissociative chemisorption of H2O on Cu(111): Quasi-seven-dimensional quantum dynamics on a refined potential energy surface. J Chem Phys 2013; 138:044704. [DOI: 10.1063/1.4776770] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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25
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Killelea DR, Utz AL. On the origin of mode- and bond-selectivity in vibrationally mediated reactions on surfaces. Phys Chem Chem Phys 2013; 15:20545-54. [DOI: 10.1039/c3cp53765j] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Jiang B, Liu R, Li J, Xie D, Yang M, Guo H. Mode selectivity in methane dissociative chemisorption on Ni(111). Chem Sci 2013. [DOI: 10.1039/c3sc51040a] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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27
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Sacchi M, Wales D, Jenkins S. Bond-selective energy redistribution in the chemisorption of CH3D and CD3H on Pt{110}-(1×2): A first-principles molecular dynamics study. COMPUT THEOR CHEM 2012. [DOI: 10.1016/j.comptc.2011.11.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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28
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Teixidor MM, Huarte-Larrañaga F. Methane dissociation on Ni(111): Reaction probabilities using direct and initial state selected approaches. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.08.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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29
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Crim FF. Molecular reaction dynamics across the phases: similarities and differences. Faraday Discuss 2012; 157:9-26; discussion 113-40. [DOI: 10.1039/c2fd20123b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Donald SB, Harrison I. Dynamically biased RRKM model of activated gas-surface reactivity: vibrational efficacy and rotation as a spectator in the dissociative chemisorption of CH4on Pt(111). Phys Chem Chem Phys 2012; 14:1784-95. [DOI: 10.1039/c2cp22895e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Jackson B, Nave S. The dissociative chemisorption of methane on Ni(100): Reaction path description of mode-selective chemistry. J Chem Phys 2011; 135:114701. [DOI: 10.1063/1.3634073] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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32
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Cushing GW, Navin JK, Valadez L, Johánek V, Harrison I. An effusive molecular beam technique for studies of polyatomic gas-surface reactivity and energy transfer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:044102. [PMID: 21529024 DOI: 10.1063/1.3577076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
An effusive molecular beam technique is described to measure alkane dissociative sticking coefficients, S(T(g), T(s); ϑ), on metal surfaces for which the impinging gas temperature, T(g), and surface temperature, T(s), can be independently varied, along with the angle of incidence, ϑ, of the impinging gas. Effusive beam experiments with T(g) = T(s) = T allow for determination of angle-resolved dissociative sticking coefficients, S(T; ϑ), which when averaged over the cos (ϑ)/π angular distribution appropriate to the impinging flux from a thermal ambient gas yield the thermal dissociative sticking coefficient, S(T). Nonequilibrium S(T(g), T(s); ϑ) measurements for which T(g) ≠ T(s) provide additional opportunities to characterize the transition state and gas-surface energy transfer at reactive energies. A resistively heated effusive molecular beam doser controls the T(g) of the impinging gas striking the surface. The flux of molecules striking the surface from the effusive beam is determined from knowledge of the dosing geometry, chamber pressure, and pumping speed. Separate experiments with a calibrated leak serve to fix the chamber pumping speed. Postdosing Auger electron spectroscopy is used to measure the carbon of the alkyl radical reaction product that is deposited on the surface as a result of alkane dissociative sticking. As implemented in a typical ultrahigh vacuum chamber for surface analysis, the technique has provided access to a dynamic range of roughly 6 orders of magnitude in the initial dissociative sticking coefficient for small alkanes on Pt(111).
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Affiliation(s)
- G W Cushing
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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33
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Vallance C. Generation, characterisation, and applications of atomic and molecular alignment and orientation. Phys Chem Chem Phys 2011; 13:14427-41. [DOI: 10.1039/c1cp21037h] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Espinosa-García J, García-Bernaldez JC. Vibrational versus translational energies in the H + CCl4 reaction: A quasi-classical trajectory study. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2010.12.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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35
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Yoder BL, Bisson R, Beck RD. Steric Effects in the Chemisorption of Vibrationally Excited Methane on Ni(100). Science 2010; 329:553-6. [DOI: 10.1126/science.1191751] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Bruce L. Yoder
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Régis Bisson
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rainer D. Beck
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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36
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Tiwari AK, Nave S, Jackson B. The temperature dependence of methane dissociation on Ni(111) and Pt(111): Mixed quantum-classical studies of the lattice response. J Chem Phys 2010; 132:134702. [DOI: 10.1063/1.3357415] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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37
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Espinosa-García J. Vibrational versus translational energies in the F+CH4 reaction: A comparison with the F+CH2D2 reaction using quasi-classical trajectory methods. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.02.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Nave S, Tiwari AK, Jackson B. Methane dissociation and adsorption on Ni(111), Pt(111), Ni(100), Pt(100), and Pt(110)-(1×2): Energetic study. J Chem Phys 2010; 132:054705. [DOI: 10.1063/1.3297885] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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39
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Tiwari AK, Nave S, Jackson B. Methane dissociation on Ni(111): a new understanding of the lattice effect. PHYSICAL REVIEW LETTERS 2009; 103:253201. [PMID: 20366254 DOI: 10.1103/physrevlett.103.253201] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Indexed: 05/11/2023]
Abstract
The nature of the lattice motion during the dissociation of methane on Ni(111) is analyzed in great detail, and various models for including lattice effects are explored. It is shown that the thermal vibrations of the lattice strongly modify the reactivity, but that the lattice motion is relatively unperturbed by the incident molecule during the collision, in contrast with several earlier predictions. Based on these studies we propose a new model to describe the effects of lattice motion, which agrees well with exact quantum calculations.
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Affiliation(s)
- Ashwani Kumar Tiwari
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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40
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Nave S, Jackson B. Methane dissociation on Ni(111) and Pt(111): Energetic and dynamical studies. J Chem Phys 2009; 130:054701. [DOI: 10.1063/1.3065800] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Espinosa-García J. Quasiclassical trajectory calculations analyzing the role of vibrational and translational energy in the F+CH2D2 reaction. J Chem Phys 2009; 130:054305. [PMID: 19206971 DOI: 10.1063/1.3069632] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Joaquín Espinosa-García
- Departamento de Química Física, Facultad de Ciencias, Universidad de Extremadura, Badajoz 06071, Spain.
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42
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Vibrational vs. translational energy in promoting a prototype metal-hydrocarbon insertion reaction. Proc Natl Acad Sci U S A 2008; 105:12673-7. [PMID: 18678904 DOI: 10.1073/pnas.0801170105] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The reaction Y + CH(4) --> HYCH(3) --> YCH(2) + H(2) is initiated by C-H insertion involving a 20 +/- 3 kcal/mol potential energy barrier. The reaction is studied in crossed molecular beams under two different conditions with nearly the same total energy. One experiment is carried out at a collision energy of 15.1 kcal/mol with one quantum of CH(4) antisymmetric (nu(3)) stretching vibrational excitation (8.63 kcal/mol), the other at a collision energy of 23.8 kcal/mol. The reaction cross-section for C-H stretch excited methane (sigma(s)) is found to be at least a factor of 2.2 times larger than for ground-state methane (sigma(g)) at the same total energy.
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43
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Crim FF. Chemical dynamics of vibrationally excited molecules: Controlling reactions in gases and on surfaces. Proc Natl Acad Sci U S A 2008; 105:12654-61. [PMID: 18765816 PMCID: PMC2529117 DOI: 10.1073/pnas.0803010105] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Indexed: 11/18/2022] Open
Abstract
Experimental studies of the chemical reaction dynamics of vibrationally excited molecules reveal the ability of different vibrations to control the course of a reaction. This Perspective describes those studies for the prototypical reaction of vibrationally excited methane and its isotopologues in gases and on surfaces and looks to the prospects of similar studies in liquids. The influences of vibrational excitation on the C-H bond cleavage in a single collision reaction with Cl and in dissociative adsorption on a Ni surface bear some striking similarities. Both reactions are bond-selective processes in which the initial preparation of a molecular eigenstate containing a large component of C-H stretching results in preferential cleavage of that bond. It is possible to cleave either the C-H bond or C-D bond in the reaction of Cl with CH3D, CH2D2, or CHD3 and, similarly, to use initial excitation of the C-H stretch to promote dissociation of CHD3 to CD3 and H on a Ni surface. Different vibrational modes, such as the symmetric and antisymmetric stretches in CH3D or CH4, lead to very different reactivities, and molecules with the symmetric stretching vibration excited can be as much as 10 times more reactive than ones with the antisymmetric stretch excited. The origin of this behavior lies in the change in the vibrational motion induced by the interaction with the atomic reaction partner or the surface.
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Affiliation(s)
- F Fleming Crim
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA.
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44
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Bisson R, Sacchi M, Dang TT, Yoder B, Maroni P, Beck RD. State-Resolved Reactivity of CH4(2ν3) on Pt(111) and Ni(111): Effects of Barrier Height and Transition State Location. J Phys Chem A 2007; 111:12679-83. [DOI: 10.1021/jp076082w] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Bisson
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - M. Sacchi
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - T. T. Dang
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - B. Yoder
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - P. Maroni
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - R. D. Beck
- Laboratoire de Chimie Physique Moléculaire, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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45
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Marsh AL, Becraft KA, Somorjai GA. Methane dissociative adsorption on the Pt(111) surface over the 300-500 K temperature and 1-10 Torr pressure ranges. J Phys Chem B 2007; 109:13619-22. [PMID: 16852706 DOI: 10.1021/jp051718+] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissociative adsorption of methane on the Pt(111) surface has been investigated and characterized over the 1-10 Torr pressure and 300-500 K temperature ranges using sum frequency generation (SFG) vibrational spectroscopy and Auger electron spectroscopy (AES). At a reaction temperature of 300 K and a pressure of 1 Torr, C-H bond dissociation occurs in methane on the Pt(111) surface to produce adsorbed methyl (CH(3)) groups, carbon, and hydrogen. SFG results suggest that C-C coupling occurs at higher reaction temperatures and pressures. At 400 K, methyl groups react with adsorbed C to form ethylidyne (C(2)H(3)), which dehydrogenates at 500 K to form ethynyl (C(2)H) and methylidyne (CH) species, as shown by SFG. By 600 K, all of the ethylidyne has reacted to form the dissociation products ethynyl and methylidyne. Calculated C-H bond dissociation probabilities for methane, determined by carbon deposition measured by AES, are in the 10(-8) range and increase with increasing reaction temperature. A mechanism has been developed and is compared with conclusions from other experimental and theoretical studies using single crystals.
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Affiliation(s)
- Anderson L Marsh
- Department of Chemistry, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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46
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Laffir FR, Harris JJ, Fiorin V, King DA. Ethane dissociation on Pt{110}-(1×2): New low-energy pathways. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.03.087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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47
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Makarov G, Petin A. High-power infrared laser induced increase of passing probability of molecules through a cooled multichannel plate. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.05.128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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48
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DeWitt KM, Valadez L, Abbott HL, Kolasinski KW, Harrison I. Using Effusive Molecular Beams and Microcanonical Unimolecular Rate Theory to Characterize CH4 Dissociation on Pt(111). J Phys Chem B 2006; 110:6705-13. [PMID: 16570976 DOI: 10.1021/jp0566865] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The dissociative sticking coefficient for CH4 on Pt(111) has been measured as a function of both gas temperature (Tg) and surface temperature (Ts) using effusive molecular beam and angle-integrated ambient gas dosing methods. The experimental results are used to optimize the three parameters of a microcanonical unimolecular rate theory (MURT) model of the reactive system. The MURT calculations allow us to extract transition state properties from the data as well as to compare our data directly to other molecular beam and thermal equilibrium sticking measurements. We find a threshold energy for dissociation of E0 = 52.5 +/- 3.5 kJ mol(-1). Furthermore, the MURT with an optimized parameter set provides for a predictive understanding of the kinetics of this C-H bond activation reaction, that is, it allows us to predict the dissociative sticking coefficient of CH4 on Pt(111) for any combination of Ts and Tg even if the two are not equal to one another, indeed, the distribution of molecular energy need not even be thermal. Comparison of our results to those from recent thermal equilibrium catalysis studies on CH4 reforming over Pt nanoclusters ( approximately 2 nm diam) dispersed on oxide substrates indicates that the reactivity of Pt(111) exceeds that of the Pt nanocatalysts by several orders of magnitude.
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Affiliation(s)
- Kristy M DeWitt
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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49
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DeWitt KM, Valadez L, Abbott HL, Kolasinski KW, Harrison I. Effusive Molecular Beam Study of C2H6 Dissociation on Pt(111). J Phys Chem B 2006; 110:6714-20. [PMID: 16570977 DOI: 10.1021/jp055684h] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dissociative sticking coefficient for C2H6 on Pt(111) has been measured as a function of both gas temperature (Tg) and surface temperature (Ts) using effusive molecular beam and angle-integrated ambient gas dosing methods. A microcanonical unimolecular rate theory (MURT) model of the reactive system is used to extract transition state properties from the data as well as to compare our data directly with supersonic molecular beam and thermal equilibrium sticking measurements. We report for the first time the threshold energy for dissociation, E0 = 26.5 +/- 3 kJ mol(-1). This value is only weakly dependent on the other two parameters of the model. A strong surface temperature dependence in the initial sticking coefficient is observed; however, the relatively weak dependence on gas temperature indicates some combination of the following (i) not all molecular excitations are contributing equally to the enhancement of sticking, (ii) that strong entropic effects in the dissociative transition state are leading to unusually high vibrational frequencies in the transition state, and (iii) energy transfer from gas-phase rovibrational modes to the surface is surprisingly efficient. In other words, it appears that vibrational mode-specific behavior and/or molecular rotations may play stronger roles in the dissociative adsorption of C2H6 than they do for CH4. The MURT with an optimized parameter set provides for a predictive understanding of the kinetics of this C-H bond activation reaction, that is, it allows us to predict the dissociative sticking coefficient of C2H6 on Pt(111) for any combination of Ts and Tg even if the two are not equal to one another.
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Affiliation(s)
- Kristy M DeWitt
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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50
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Bukoski A, Abbott HL, Harrison I. Microcanonical unimolecular rate theory at surfaces. III. Thermal dissociative chemisorption of methane on Pt(111) and detailed balance. J Chem Phys 2005; 123:94707. [PMID: 16164362 DOI: 10.1063/1.2006679] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A local hot spot model of gas-surface reactivity is used to investigate the state-resolved dynamics of methane dissociative chemisorption on Pt(111) under thermal equilibrium conditions. Three Pt surface oscillators, and the molecular vibrations, rotations, and the translational energy directed along the surface normal are treated as active degrees of freedom in the 16-dimensional microcanonical kinetics. Several energy transfer models for coupling a local hot spot to the surrounding substrate are developed and evaluated within the context of a master equation kinetics approach. Bounds on the thermal dissociative sticking coefficient based on limiting energy transfer models are derived. The three-parameter physisorbed complex microcanonical unimolecular rate theory (PC-MURT) is shown to closely approximate the thermal sticking under any realistic energy transfer model. Assuming an apparent threshold energy for CH(4) dissociative chemisorption of E(0)=0.61 eV on clean Pt(111), the PC-MURT is used to predict angle-resolved yield, translational, vibrational, and rotational distributions for the reactive methane flux at thermal equilibrium at 500 K. By detailed balance, these same distributions should be observed for the methane product from methyl radical hydrogenation at 500 K in the zero coverage limit if the methyl radicals are not subject to side reactions. Given that methyl radical hydrogenation can only be experimentally observed when the CH(3) radicals are kinetically stabilized against decomposition by coadsorbed H, the PC-MURT was used to evaluate E(0) in the high coverage limit. A high coverage value of E(0)=2.3 eV adequately reproduced the experimentally observed methane angular and translational energy distributions from thermal hydrogenation of methyl radicals. Although rigorous application of detailed balance arguments to this reactive system cannot be made because thermal decomposition of the methyl radicals competes with hydrogenation, approximate applicability of detailed balance would argue for a strong coverage dependence of E(0) with H coverage--a dependence not seen for methyl radical hydrogenation on Ru(0001), but not yet experimentally explored on Pt(111).
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Affiliation(s)
- A Bukoski
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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