51
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Density Functional Theory Study of Selectivity Considerations for C–C Versus C–O Bond Scission in Glycerol Decomposition on Pt(111). Top Catal 2012. [DOI: 10.1007/s11244-012-9806-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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52
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53
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Lin S, Xie D, Guo H. First-principles study of the methyl formate pathway of methanol steam reforming on PdZn(111) with comparison to Cu(111). ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcata.2012.01.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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54
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Zeng CH, Yang YY, Zhu YM, Wang HM, Chu TS, Ng SW. A New Luminescent Terbium 4-methylsalicylate Complex as a Novel Sensor for Detecting the Purity of Methanol. Photochem Photobiol 2012; 88:860-6. [DOI: 10.1111/j.1751-1097.2012.01123.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Ye J, Liu C, Ge Q. A DFT study of methanol dehydrogenation on the PdIn(110) surface. Phys Chem Chem Phys 2012; 14:16660-7. [DOI: 10.1039/c2cp42183f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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56
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Mehmood F, Rankin RB, Greeley J, Curtiss LA. Trends in methanol decomposition on transition metal alloy clusters from scaling and Brønsted–Evans–Polanyi relationships. Phys Chem Chem Phys 2012; 14:8644-52. [DOI: 10.1039/c2cp00052k] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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57
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Zaman S, Smith KJ. A Review of Molybdenum Catalysts for Synthesis Gas Conversion to Alcohols: Catalysts, Mechanisms and Kinetics. CATALYSIS REVIEWS-SCIENCE AND ENGINEERING 2012. [DOI: 10.1080/01614940.2012.627224] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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58
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Lawton TJ, Carrasco J, Baber AE, Michaelides A, Sykes ECH. Hydrogen-bonded assembly of methanol on Cu(111). Phys Chem Chem Phys 2012; 14:11846-52. [DOI: 10.1039/c2cp41875d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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59
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Medlin JW. Understanding and Controlling Reactivity of Unsaturated Oxygenates and Polyols on Metal Catalysts. ACS Catal 2011. [DOI: 10.1021/cs200336r] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Will Medlin
- Renewable and Sustainable Energy Institute, Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309-0424, United States
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60
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Lin S, Xie D, Guo H. Methyl Formate Pathway in Methanol Steam Reforming on Copper: Density Functional Calculations. ACS Catal 2011. [DOI: 10.1021/cs200311t] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sen Lin
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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61
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Zhao YF, Yang Y, Mims C, Peden CH, Li J, Mei D. Insight into methanol synthesis from CO2 hydrogenation on Cu(111): Complex reaction network and the effects of H2O. J Catal 2011. [DOI: 10.1016/j.jcat.2011.04.012] [Citation(s) in RCA: 281] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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62
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Lin S, Johnson RS, Smith GK, Xie D, Guo H. Pathways for methanol steam reforming involving adsorbed formaldehyde and hydroxyl intermediates on Cu(111): density functional theory studies. Phys Chem Chem Phys 2011; 13:9622-31. [PMID: 21487630 DOI: 10.1039/c1cp20067d] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plane-wave density functional theory calculations have been carried out to explore possible pathways in methanol steam reforming (MSR) on Cu(111). We focus on reactions involving the adsorbed formaldehyde intermediate (CH(2)O) produced by methanol decomposition and the surface hydroxyl (OH) species generated by dissociative adsorption of H(2)O. Several possible pathways leading to the H(2) + CO(2) products have been identified. The two most likely pathways involve the formate (CHOO), rather than the carboxyl (COOH), intermediate, and they possess barriers lower than that of the rate-limiting step of MSR, namely the dehydrogenation of adsorbed methoxyl (CH(3)O) species.
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Affiliation(s)
- Sen Lin
- Institute of Theoretical and Computational Chemistry, Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
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63
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Ren R, Niu C, Bu S, Zhou Y, Lv Y, Wang G. Why is metallic Pt the best catalyst for methoxy decomposition? ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s1003-9953(10)60158-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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64
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Du Y, Chen W, Zhang Y, Guo X. Study of CO adsorption on perfect and defective pyrite(100) surfaces by density functional theory. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/s1003-9953(10)60146-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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65
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Mehmood F, Greeley J, Zapol P, Curtiss LA. Comparative Density Functional Study of Methanol Decomposition on Cu4 and Co4 Clusters. J Phys Chem B 2010; 114:14458-66. [DOI: 10.1021/jp101594z] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- F. Mehmood
- Materials Science Division and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. Greeley
- Materials Science Division and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - P. Zapol
- Materials Science Division and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. A. Curtiss
- Materials Science Division and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
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66
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Zaman SF, Smith KJ. A DFT study of the effect of K and SiO2on syngas conversion to methane and methanol over an Mo6P3cluster. MOLECULAR SIMULATION 2010. [DOI: 10.1080/08927020903124585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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67
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Niu CY, Jiao J, Xing B, Wang GC, Bu XH. Reaction mechanism of methanol decomposition on Pt-based model catalysts: A theoretical study. J Comput Chem 2010; 31:2023-37. [DOI: 10.1002/jcc.21487] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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68
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Yang Y, Evans J, Rodriguez JA, White MG, Liu P. Fundamental studies of methanol synthesis from CO2 hydrogenation on Cu(111), Cu clusters, and Cu/ZnO(0001̄). Phys Chem Chem Phys 2010; 12:9909-17. [DOI: 10.1039/c001484b] [Citation(s) in RCA: 368] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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69
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Radilla J, Boronat M, Corma A, Illas F. Monitoring the interaction of adsorbates on metal surfaces by surface site engineering: the case of ethoxy on Cu, Pd, Ag and Au regular and stepped surfaces. Phys Chem Chem Phys 2010; 12:6492-8. [DOI: 10.1039/c000405g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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70
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Xu L, Mei D, Henkelman G. Adaptive kinetic Monte Carlo simulation of methanol decomposition on Cu(100). J Chem Phys 2009; 131:244520. [DOI: 10.1063/1.3281688] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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71
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Manz TA, Sholl DS. A dimensionless reaction coordinate for quantifying the lateness of transition states. J Comput Chem 2009; 31:1528-41. [PMID: 19908292 DOI: 10.1002/jcc.21440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The Hammond-Leffler postulate asserts that transition states of exothermic reactions are reactant-like (early), whereas transition states of endothermic reactions are product-like (late). Related postulates have been proposed to describe the sensitivity of activation barriers for reactions occurring on catalytic surfaces to the catalyst structure. To evaluate the validity of these postulates for different chemical reactions, a general method for classifying transition states as either early or late is needed. One can envision a dimensionless reaction coordinate that changes continuously and monotonically from 0 to 1 along a minimum energy reaction pathway. The value of the dimensionless reaction coordinate for the transition state (W(TS)) classifies transition states as (a) early when W(TS) < 0.5, (b) late when W(TS) > 0.5, and (c) equidistant between reactants and products when W(TS) = 0.5. In this article, we derive such a dimensionless reaction coordinate and illustrate its usefulness for several different chemical reactions.
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Affiliation(s)
- Thomas A Manz
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive N.W., Atlanta, Georgia 30332-0100, USA.
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72
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73
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Montoya A, Haynes BS. DFT Analysis of the Reaction Paths of Formaldehyde Decomposition on Silver. J Phys Chem A 2009; 113:8125-31. [DOI: 10.1021/jp901134d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alejandro Montoya
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
| | - Brian S. Haynes
- School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, NSW 2006, Australia
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74
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Gazdzicki P, Uvdal P, Jakob P. Adsorption of intact methanol on Ru(0001). J Chem Phys 2009; 130:224703. [DOI: 10.1063/1.3151674] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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75
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Croy JR, Mostafa S, Heinrich H, Cuenya BR. Size-selected Pt Nanoparticles Synthesized via Micelle Encapsulation: Effect of Pretreatment and Oxidation State on the Activity for Methanol Decomposition and Oxidation. Catal Letters 2009. [DOI: 10.1007/s10562-009-0042-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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76
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Density-functional calculation of the adsorption and reaction of CO and H2O molecules over a 4Rh/CeO2(111) surface. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2008.02.064] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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77
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Gokhale AA, Dumesic JA, Mavrikakis M. On the mechanism of low-temperature water gas shift reaction on copper. J Am Chem Soc 2008; 130:1402-14. [PMID: 18181624 DOI: 10.1021/ja0768237] [Citation(s) in RCA: 477] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Periodic, self-consistent density functional theory (DFT-GGA) calculations are used to investigate the water gas shift reaction (WGSR) mechanism on Cu(111). The thermochemistry and activation energy barriers for all the elementary steps of the commonly accepted redox mechanism, involving complete water activation to atomic oxygen, are presented. Through our calculations, we identify carboxyl, a new reactive intermediate, which plays a central role in WGSR on Cu(111). The thermochemistry and activation energy barriers of the elementary steps of a new reaction path, involving carboxyl, are studied. A detailed DFT-based microkinetic model of experimental reaction rates, accounting for both the previous and the new WGSR mechanism show that, under relevant experimental conditions, (1) the carboxyl-mediated route is the dominant path, and (2) the initial hydrogen abstraction from water is the rate-limiting step. Formate is a stable "spectator" species, formed predominantly through CO2 hydrogenation. In addition, the microkinetic model allows for predictions of (i) surface coverage of intermediates, (ii) WGSR apparent activation energy, and (iii) reaction orders with respect to CO, H2O, CO2, and H2.
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Affiliation(s)
- Amit A Gokhale
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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78
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Sakong S, Gross A. Total Oxidation of Methanol on Cu(110): A Density Functional Theory Study. J Phys Chem A 2007; 111:8814-22. [PMID: 17705455 DOI: 10.1021/jp072773g] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The partial and total oxidation of methanol on clean and oxygen-precovered Cu(110) has been studied by periodic density functional theory calculations within the generalized gradient approximation. Reaction paths including the geometry and the energetics of several reaction intermediates and the activation barriers between them have been determined, thus creating a complete scheme for methanol oxidation on copper. The calculations demonstrate that the specific structure of oxygen on copper plays an important role in both the partial and the total oxidation of methanol. For lower oxygen concentrations on the surface, the partial oxidation of methanol to formaldehyde is promoted by the presence of oxygen on the surface through the removal of hydrogen in the form of water, which prevents the recombinative desorption of methanol. At larger oxygen concentrations, the presence of isolated oxygen atoms reduces the C-H bond breaking barrier of adsorbed methoxy considerably, thus accelerating the formation of formaldehyde. Furthermore, oxygen also promotes the formation of dioxymethylene from formaldehyde, which then easily decays to formate. Formate is the most stable reaction intermediate in the total oxidation. Thus the formate decomposition represents the rate-limiting step in the total oxidation of methanol on copper.
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Affiliation(s)
- Sung Sakong
- Institut für Theoretische Chemie, Universität Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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79
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Gomes JRB, Gonzalez S, Torres D, Illas F. Exploring the molecular mechanisms of reactions at surfaces. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2007. [DOI: 10.1134/s1990793107040033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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80
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Pang XY, Xue LQ, Wang GC. Adsorption of atoms on cu surfaces: a density functional theory study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:4910-7. [PMID: 17388612 DOI: 10.1021/la063097x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The chemisorption of atoms (H, N, S, O, and C) on Cu surfaces has been systematically studied by the density functional theory generalized gradient approximation method with the slab model. Our calculated results indicate that the orders of the adsorption energy are H < N < S < O < C on Cu(111) and H < N < O < S < C on Cu(110) and Cu(100). Furthermore, the adsorption energies of the given atoms on Cu(100) are larger than those on Cu(111) and Cu(110). The preferred adsorption sites are a 3-fold hollow site on Cu(111) and a 4-fold hollow site on Cu(100), but the preferred adsorption sites on Cu(110) are different for different adatoms. The energy, as well as the geometry, is in good agreement with the experimental and other theoretical data. In addition, this study focuses on the electronic and geometric properties of the metal-atom (M-A) bond to explain the difference in adsorption energies among adatoms. A detailed investigation of the density of states curves explains the nature of the most stable site. Finally, we test the effect of the coverage and find that the surface coverage has no influence on the preferred adsorption sites of the given adatoms on Cu(110) with the exception of hydrogen and oxygen, but has much influence on the value of the adsorption energy.
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Affiliation(s)
- Xian-Yong Pang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China
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81
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Tao SX, Wang GC, Bu XH. Effect of pre-covered oxygen on the dehydrogenation reactions over copper surface: a density functional theory study. J Phys Chem B 2007; 110:26045-54. [PMID: 17181256 DOI: 10.1021/jp0649495] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehydrogenation of five species including CH3OH, CH3O, H2COO, NH3, and H2O over clean and oxygen-modified copper surfaces has been investigated by the first-principle density functional calculations within the generalized gradient approximation. The reaction enthalpies and the activation energies have been calculated for 10 elementary steps corresponding to the direct and oxygen-assisted cleavage of X-H bonds (X = O, N, C). The DFT-GGA results showed that the pre-adsorbed oxygen always facilitates the dehydrogenation reaction by decreasing the reaction enthalpies and the activation energies. The obtained results are in general agreement with experimental observations.
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Affiliation(s)
- Shu-Xia Tao
- Department of Chemistry and the Center of Theoretical Chemistry Study, Nankai University, Tianjin 300071, People's Republic of China
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82
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Hsu WD, Ichihashi M, Kondow T, Sinnott SB. Ab Initio Molecular Dynamics Study of Methanol Adsorption on Copper Clusters. J Phys Chem A 2006; 111:441-9. [PMID: 17228892 DOI: 10.1021/jp065669s] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preferential structures of small copper clusters Cun (n=2-9) and the adsorption of methanol molecules on these clusters are examined with first principles, molecular dynamics simulations. The results show that the copper clusters undergo systematic changes in bond length and bond order associated with altering their preferential structures from one-dimensional structures, to two-dimensional and three-dimensional structures. The results also indicate that low coordination number sites on the copper clusters are both the most favorable for methanol adsorption and have the greatest localization of electronic charge. The simulations predict that charge transfer between the neutral copper clusters and the incident methanol molecules is a key process by which adsorption is stabilized. Importantly, the changes in the dimensionality of the copper clusters do not significantly influence methanol adsorption.
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Affiliation(s)
- Wen-Dung Hsu
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400, USA
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83
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DFT studies of methanol decomposition on Ni(100) surface: Compared with Ni(111) surface. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcata.2006.04.013] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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84
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Adsorption and dissociation of methanol on Au(1 1 1) surface: A first-principles periodic density functional study. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.theochem.2006.05.040] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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85
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Lim KH, Chen ZX, Neyman KM, Rösch N. Comparative Theoretical Study of Formaldehyde Decomposition on PdZn, Cu, and Pd Surfaces. J Phys Chem B 2006; 110:14890-7. [PMID: 16869600 DOI: 10.1021/jp061410y] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methanol steam reforming, catalyzed by Pd/ZnO (PdZn alloy), is a potential source of hydrogen for on-board fuel cells. CO has been reported to be a minor side product of methanol decomposition that occurs in parallel to methanol steam reforming on PdZn catalysts. However, fuel cells currently used in vehicles are very sensitive to CO poisoning. To contribute to the understanding of pertinent reaction mechanisms, we employed density functional slab model calculations to study the decomposition of formaldehyde, a key intermediate in methanol decomposition and steam reforming reactions, on planar surfaces of Pd, Cu, and PdZn as well as on a stepped surface of PdZn. The calculated activation energies indicate that dehydrogenation of formaldehyde is favorable on Pd(111), but unfavorable on Cu(111) and PdZn(111). On the stepped PdZn(221) surface, the dehydrogenation process was calculated to be more competitive to formaldehyde desorption than on PdZn(111). Thus, we ascribe the experimentally observed small amount of CO, formed during steam reforming of methanol on the Pd/ZnO catalyst, to occur at metallic Pd species of the catalyst or at defect sites of PdZn alloy.
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Affiliation(s)
- Kok Hwa Lim
- Department Chemie, Technische Universität München, 85747 Garching, Germany
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86
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Li J, Li RF, Wang GC. A Systematic Density Functional Theory Study of the C−N Bond Cleavage of Methylamine on Metals. J Phys Chem B 2006; 110:14300-3. [PMID: 16854136 DOI: 10.1021/jp062975x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The C-N bond cleavage for the relative large molecule of methylamine on Cu(1111), Ag(111), Au(111), Ni(111), Rh(111), Pd(111), Pt(111), and Mo(100) has been systemically studied using the DFT-GGA method; the reaction energy changes and the activation energies were obtained. The calculated results show that the activation energy of C-N bond cleavage decreases as the metal element goes up and to the left across the periodic table, which is in general agreement with the experimental observation. Moreover, it was found that the steric effect should be considered for the metals with high activity and small radius such as Ni, which is much different from the case for the small molecule decomposition in which the steric effect may be ignored. The linear relationships between the activation energies and electronic properties (d-band center) are presented. It is expected that such a rule can be used to predict the reactivity of metal for other dissociative adsorption systems.
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Affiliation(s)
- Jun Li
- Department of Chemistry, and the Center of Theoretical Chemistry Study, Nankai University, Tianjin 300071, People's Republic of China
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87
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Chen WK, Liu SH, Cao MJ, Lu CH, Xu Y, Li JQ. Adsorption of Methanol and Methoxy on Cu(111) Surface: A First-principles Periodic Density Functional Theory Study. CHINESE J CHEM 2006. [DOI: 10.1002/cjoc.200690166] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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88
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Ye P, Gellman AJ. Transition State for β-Hydride Elimination in Alkyl Groups on Pt(111). J Phys Chem B 2006; 110:9660-6. [PMID: 16686516 DOI: 10.1021/jp061047v] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The transition state for beta-hydride elimination in alkyl groups on the Pt(111) surface has been probed by studying the effects of fluorine substitution on the barriers to beta-hydride elimination, DeltaE++(betaH). Four different fluoroalkyl groups have been formed on the Pt(111) surface by dissociative adsorption of four fluoroalkyl iodides: RCH(2)CH(2)-I (R = CF(3), CF(3)CH(2), and CF(3)CF(2)) and (CF(3))(2)CHCH(2)-I. In the absence of preadsorbed hydrogen, fluoroalkyl groups on the Pt(111) surface dehydrogenate via beta-hydride elimination to form unsaturated fluorocarbons and deposit hydrogen atoms onto the surface. Those hydrogen atoms then hydrogenate the remaining fluoroalkyl groups to produce fluoroalkanes that desorb rapidly from the surface. The kinetics of hydrogenation and fluoroalkane desorption are rate limited by the beta-hydride elimination step and thus serve as measures of the kinetics of beta-hydride elimination. The field effects of the fluorinated substituents increase the barriers to beta-hydride elimination with a reaction constant of rho(F) = 19 +/- 2 kJ/mol. The interpretation of this effect is that the beta-carbon atom in the transition state is cationic, [RC(delta+...)H]++, with respect to the reactant. The field effect of the fluorinated substituent energetically destabilizes the electron deficient beta-carbon atom in the transition state. This is consistent with observations made on the Cu(111) surface; however, the substituent effect is significantly smaller on the Pt(111) surface. On the Pt(111) surface, the transition state for beta-hydride elimination is less polarized with respect to the initial state alkyl group than on the Cu(111) surface.
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Affiliation(s)
- Pingping Ye
- Department of Chemistry and Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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89
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Tominaga H, Nagai M. Density Functional Theory of Water−Gas Shift Reaction on Molybdenum Carbide. J Phys Chem B 2005; 109:20415-23. [PMID: 16853642 DOI: 10.1021/jp053706u] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The density functional theory (DFT) of the water-gas shift (WGS) reaction over molybdenum carbide was studied with the aim of understanding the dissociation of H(2)O, the OH group, and CO to determine on what sections of molybdenum carbide CO(2) and H(2) formed and whether they played a role in the reaction. The energy diagram of each elementary step, the reaction of the hydrogen and oxygen atoms with CO, and the transition state for this elementary step were also studied. The IR spectra of the CO adsorption was experimentally analyzed for the identification of several candidates of the CO adsorption modes. The adsorptions of the threefold Mo site (a) with and (b) without the underlying C atom of the second layer have the second and highest adsorption energies of -281.59 and -321.00 kJ/mol, respectively. The IR data showed that the bands at 1626 cm(-1) from the IR experiments are (a) the nearest adsorption of the threefold Mo site with the underlying C atom at the calculated/corrected band of 1621 cm(-1). The calculated/corrected threefold adsorption (b) had the highest adsorption energy but exhibited an IR band at 1147 cm(-1) which was not observed in the experimental data. The C-O bond length increased to 1.49 from 1.36 after the H(2)O adsorption (b), suggesting the dissociation of C-O after the H(2)O coadsorption. The WGS reaction on the beta-Mo(2)C(001) slab carbide was calculated and took place as follows: H(2)O was dissociated into OH and H on the Mo(2)C surface and the OH subsequently dissociated into H and O atoms. CO approached the O atom to form CO(2).
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Affiliation(s)
- Hiroyuki Tominaga
- Graduate School of Bio-applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2-24 Nakamachi, Koganei, Tokyo 184-8588, Japan
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90
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Wang GC, Zhou YH, Morikawa Y, Nakamura J, Cai ZS, Zhao XZ. Kinetic Mechanism of Methanol Decomposition on Ni(111) Surface: A Theoretical Study. J Phys Chem B 2005; 109:12431-42. [PMID: 16852538 DOI: 10.1021/jp0463969] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The decomposition of methanol on the Ni(111) surface has been studied with the pseudopotential method of density functional theory-generalized gradient approximation (DFT-GGA) and with the repeated slab models. The adsorption energies of possible species and the activation energy barriers of the possible elementary reactions involved are obtained in the present work. The major reaction path on Ni surfaces involves the O-H bond breaking in CH(3)OH and the further decomposition of the resulting methoxy species to CO and H via stepwise hydrogen abstractions from CH(3)O. The abstraction of hydrogen from methoxy itself is the rate-limiting step. We also confirm that the C-O and C-H bond-breaking paths, which lead to the formation of surface methyl and hydroxyl and hydroxymethyl and atom hydrogen, respectively, have higher energy barriers. Therefore, the final products are the adsorbed CO and H atom.
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Affiliation(s)
- Gui-Chang Wang
- Department of Chemistry, and the Center of Theoretical Chemistry Study, Nankai University, Tianjin, 300071, P. R. China.
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91
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92
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Li X, Gellman AJ, Sholl DS. Orientation of ethoxy, mono-, di-, and tri-fluoroethoxy on Cu(111): a DFT study. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2004.09.072] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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93
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González S, Sousa C, Illas F. Theoretical Study of CO and NO Chemisorption on RhCu(111) Surfaces. J Phys Chem B 2005; 109:4654-61. [PMID: 16851545 DOI: 10.1021/jp0454016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A systematic density functional theory study using periodic models is presented concerning the chemisorption of CO and NO on various sites of RhCu(111) surfaces. The properties of the adsorbed molecules on various mono- and bimetallic sites of these alloy surfaces have been obtained and compared to those corresponding to the pure Rh(111) and Cu(111) surfaces. It is shown that that the interaction of small probe molecules such as CO or NO on RhCu alloys is essentially dominated by the atomic nature of the surface active site with little influence of the rest of the metallic system. Moreover, it is suggested that it is possible to control the adsorption site of these molecules by appropriate choice of the surface composition.
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Affiliation(s)
- Silvia González
- Departament de Química Física i Centre Especial de Recerca en Química Teorica, Universitat de Barcelona i Parc Científic de Barcelona, C/Martí i Franquès 1, 08028 Barcelona, Spain
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94
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95
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Wang GC, Zhou YH, Nakamura J. Characterization of methoxy adsorption on some transition metals: A first principles density functional theory study. J Chem Phys 2005; 122:44707. [PMID: 15740283 DOI: 10.1063/1.1839552] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Based on the gradient-density functional theory, calculation results of methoxy adsorption on Au(111), Ag(111), Cu(111), Pt(111), Pd(111), Ni(111), Rh(111), and Fe(100) surfaces are presented, and a consistent picture for some key physical properties determining the reactivity of metals appears. These eight metals belong to two groups: either with filled d electrons (group IB) or with unfilled but more than half filled d electrons (group VIII). The calculated adsorption energies are quite in agreement with the experimental data as well as the previous theoretical calculation results. Importantly, using the analysis of B. Hammer and J. K. Norskov, Nature (London) 376, 232 (1995) and in Chemisorption and Reactivity on Supported Clusters and Thin Films, edited by R. M. Lambert and G. Pacchioni (Kluwer Academic, Dordrecht, 1997), pp. 285-351, the binding energies have selectively been linearly correlated to the d-band center and to the size of the metal d-band orbital overlapping with the adsorbate (coupling matrix element) for these two groups of metals. And by analyzing the nature of the adsorption bonding, the possible reason of this difference is suggested.
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Affiliation(s)
- Gui-Chang Wang
- Department of Chemistry and the Center of Theoretical Chemistry Study, Nankai University, Tianjin 300071, People's Republic of China
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96
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Molecular-level descriptions of surface chemistry in kinetic models using density functional theory. Chem Eng Sci 2004. [DOI: 10.1016/j.ces.2004.09.038] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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97
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Chen ZX, Neyman KM, Lim KH, Rösch N. CH3O decomposition on PdZn(111), Pd(111), and Cu(111). A theoretical study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:8068-8077. [PMID: 15350074 DOI: 10.1021/la049377z] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Methanol steam re-forming, catalyzed by Pd/ZnO, is a potential hydrogen source for fuel cells, in particular in pollution-free vehicles. To contribute to the understanding of pertinent reaction mechanisms, density functional slab model studies on two competing decomposition pathways of adsorbed methoxide (CH(3)O) have been carried out, namely, dehydrogenation to formaldehyde and C-O bond breaking to methyl. For the (111) surfaces of Pd, Cu, and 1:1 Pd-Zn alloy, adsorption complexes of various reactants, intermediates, transition states, and products relevant for the decomposition processes were computationally characterized. On the surface of Pd-Zn alloy, H and all studied C-bound species were found to prefer sites with a majority of Pd atoms, whereas O-bound congeners tend to be located on sites with a majority of Zn atoms. Compared to Pd(111), the adsorption energy of O-bound species was calculated to be larger on PdZn(111), whereas C-bound moieties were less strongly adsorbed. C-H scission of CH(3)O on various substrates under study was demonstrated to proceed easier than C-O bond breaking. The energy barrier for the dehydrogenation of CH(3)O on PdZn(111) (113 kJ mol(-)(1)) and Cu(111) (112 kJ mol(-)(1)) is about 4 times as high as that on Pd(111), due to the fact that CH(3)O interacts more weakly with Pd than with PdZn and Cu surfaces. Calculated results showed that the decomposition of methoxide to formaldehyde is thermodynamically favored on Pd(111), but it is an endothermic process on PdZn(111) and Cu(111) surfaces.
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Affiliation(s)
- Zhao-Xu Chen
- Department Chemie, Technische Universität München, 85747 Garching, Germany
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98
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Kinetic studies of gas-phase hydrogenolysis of methyl formate to methanol over copper-based catalyst. Catal Today 2004. [DOI: 10.1016/j.cattod.2004.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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99
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Gokhale AA, Huber GW, Dumesic JA, Mavrikakis M. Effect of Sn on the Reactivity of Cu Surfaces. J Phys Chem B 2004. [DOI: 10.1021/jp048013c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amit A. Gokhale
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - George W. Huber
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - James A. Dumesic
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
| | - Manos Mavrikakis
- Department of Chemical and Biological Engineering, University of WisconsinMadison, 1415 Engineering Drive, Madison, Wisconsin 53706
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100
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Williams SM, Rodriguez KR, Teeters-Kennedy S, Stafford AD, Bishop SR, Lincoln UK, Coe JV. Use of the Extraordinary Infrared Transmission of Metallic Subwavelength Arrays To Study the Catalyzed Reaction of Methanol to Formaldehyde on Copper Oxide. J Phys Chem B 2004. [DOI: 10.1021/jp0489368] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shaun M. Williams
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - Kenneth R. Rodriguez
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - Shannon Teeters-Kennedy
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - Amanda D. Stafford
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - Sarah R. Bishop
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - Ushani K. Lincoln
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
| | - James V. Coe
- Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1173
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