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Tezsevin I, van Santen RA, Onal I. A density functional theory study of propylene epoxidation mechanism on Ag2O(001) surface. Phys Chem Chem Phys 2018; 20:26681-26687. [DOI: 10.1039/c8cp04210a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Propylene oxide is the most probable outcome of propylene–silver oxide interaction; however, it further reacts to give an allyl radical.
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Affiliation(s)
- I. Tezsevin
- Department of Chemical Engineering
- Middle East Technical University
- Ankara
- Turkey
- Department of Chemical Engineering and Chemistry
| | - R. A. van Santen
- Department of Chemical Engineering and Chemistry
- Eindhoven University of Technology
- Eindhoven
- The Netherlands
| | - I. Onal
- Department of Chemical Engineering
- Middle East Technical University
- Ankara
- Turkey
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Abstract
Scaling rules differ for early and late transition metals. Their electronic structure and topological bond analysis are shown.
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Affiliation(s)
- R. A. van Santen
- Institute for Complex Molecular Systems
- Eindhoven University of Technology
- Eindhoven
- Netherlands
- Department of Chemical Engineering and Chemistry
| | - I. Tranca
- Department of Chemical Engineering and Chemistry
- Eindhoven University of Technology
- Eindhoven
- Netherlands
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Abstract
The increasing availability of quantum-chemical data on surface reaction intermediates invites one to revisit unresolved mechanistic issues in heterogeneous catalysis. One such issue of particular current interest is the molecular basis of the Fischer-Tropsch reaction. Here we review current molecular understanding of this reaction that converts synthesis gas into longer hydrocarbons where we especially elucidate recent progress due to the contributions of computational catalysis. This perspective highlights the theoretical approach to heterogeneous catalysis that aims for kinetic prediction from quantum-chemical first principle data. Discussion of the Fischer-Tropsch reaction from this point of view is interesting because of the several mechanistic options available for this reaction. There are many proposals on the nature of the monomeric single C atom containing intermediate that is inserted into the growing hydrocarbon chain as well as on the nature of the growing hydrocarbon chain itself. Two dominant conflicting mechanistic proposals of the Fischer-Tropsch reaction that will be especially compared are the carbide mechanism and the CO insertion mechanism, which involve cleavage of the C-O bond of CO before incorporation of a CHx species into the growing hydrocarbon chain (the carbide mechanism) or after incorporation into the growing hydrocarbon chain (the CO insertion mechanism). The choice of a particular mechanism has important kinetic consequences. Since it is based on molecular information it also affects the structure sensitivity of this particular reaction and hence influences the choice of catalyst composition. We will show how quantum-chemical information on the relative stability of relevant reaction intermediates and estimates of the rate constants of corresponding elementary surface reactions provides a firm foundation to the kinetic analysis of such reactions and allows one to discriminate between the different mechanistic options. The paper will be concluded with a short perspective section dealing with the needs for future research. Many of the current key questions on the physical chemistry as well as computational study of heterogeneous catalysis relate to particular topics for further research on the fundamental aspects of Fischer-Tropsch catalysis.
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Affiliation(s)
- R A van Santen
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600MB, Eindhoven, The Netherlands.
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Abstract
A comprehensive density functional theory study of the Fischer–Tropsch mechanism on the corrugated Ru(112̄1) surface has been carried out.
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Affiliation(s)
- I. A. W. Filot
- Laboratory of Inorganic Materials Chemistry
- Schuit Institute of Catalysis
- Technische Universiteit Eindhoven
- 5600 MB Eindhoven, The Netherlands
| | - R. A. van Santen
- Laboratory of Inorganic Materials Chemistry
- Schuit Institute of Catalysis
- Technische Universiteit Eindhoven
- 5600 MB Eindhoven, The Netherlands
| | - E. J. M. Hensen
- Laboratory of Inorganic Materials Chemistry
- Schuit Institute of Catalysis
- Technische Universiteit Eindhoven
- 5600 MB Eindhoven, The Netherlands
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van Tilborg WJM, Smit CJ, van Santen RA. The role of tetraalkylammonium salts in the electro-reduction of ketones. Part II: The reduction of acetophenone in an aprotic environment. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19790981103] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hermse CGM, Jansen MMM, van Bavel AP, Lukkien JJ, van Santen RA, Jansen APJ. On the nature of dense CO adlayers on fcc(100) surfaces: a kinetic Monte Carlo study. Phys Chem Chem Phys 2010; 12:461-73. [DOI: 10.1039/b911322c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- C G M Hermse
- Schuit Institute of Catalysis, ST/SKA, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
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Markvoort AJ, Spijker P, Smeijers AF, Pieterse K, van Santen RA, Hilbers PAJ. Vesicle deformation by draining: geometrical and topological shape changes. J Phys Chem B 2009; 113:8731-7. [PMID: 19485364 DOI: 10.1021/jp901277h] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A variety of factors, including changes in temperature or osmotic pressure, can trigger morphological transitions of vesicles. Upon osmotic upshift, water diffuses across the membrane in response to the osmotic difference, resulting in a decreased vesicle volume to membrane area ratio and, consequently, a different shape. In this paper, we study the vesicle deformations on osmotic deflation using coarse grained molecular dynamics simulations. Simple deflation of a spontaneously formed spherical vesicle results in oblate ellipsoid and discous vesicles. However, when the hydration of the lipids in the outer membrane leaflet is increased, which can be the result of a changed pH or ion concentration, prolate ellipsoid, pear-shaped and budded vesicles are formed. Under certain conditions the deflation even results in vesicle fission. The simulations also show that vesicles formed by a bilayer to vesicle transition are, although spontaneously formed, not immediately stress-free. Instead, the membrane is stretched during the final stage of the transition and only reaches equilibrium once the excess interior water has diffused across the membrane. This suggests the presence of residual membrane stress immediately after vesicle closure in experimental vesicle formation and is especially important for MD simulations of vesicles where the time scale to reach equilibrium is out of reach.
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Affiliation(s)
- A J Markvoort
- Department of Biomedical Engineering, Eindhoven University of Technology, The Netherlands
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Affiliation(s)
- J C W Swart
- Department of Chemical Engineering, University of Cape Town, Rondebosch, 7701, South Africa
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Santen RAV, Offermans WK, Ricart JM, Novell-Leruth G, Pérez-Ramírez J. Structure dependence of Pt surface activated ammonia oxidation. ACTA ACUST UNITED AC 2008. [DOI: 10.1088/1742-6596/117/1/012028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Shape transformations and topological changes of lipid vesicles, such as fusion, budding, and fission, have important chemical physical and biological significance. In this paper, we study the fission process of lipid vesicles. Two distinct routes are considered that are both based on an asymmetry of the lipid distribution within the membrane. This asymmetry consists of a nonuniform distribution of two types of lipids. In the first mechanism, the two types of lipids are equally distributed over both leaflets of the membrane. Phase separation of the lipids within both leaflets, however, results in the formation of rafts, which form buds that can split off. In the second mechanism, the asymmetry consists of a difference in composition between the two monolayers of the membrane. This difference in composition yields a spontaneous curvature, reshaping the vesicle into a dumbbell such that it can split. Both pathways are studied with molecular dynamics simulations using a coarse-grained lipid model. For each of the pathways, the conditions required to obtain complete fission are investigated, and it is shown that for the second pathway, much smaller differences between the lipids are needed to obtain fission than for the first pathway. Furthermore, the lipid composition of the resulting split vesicles is shown to be completely different for both pathways, and essential differences between the fission pathway and the pathway of the inverse process, i.e., fusion, are shown to exist.
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Affiliation(s)
- A J Markvoort
- Departments of Biomedical Engineering and Chemical Engineering, TU Eindhoven, Postbus 513, 5600 MB Eindhoven, The Netherlands.
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Abstract
Lipid bilayer membranes are known to form various structures such as large sheets or vesicles. When the two leaflets of the bilayer have an equal composition, the membrane preferentially forms a flat sheet or a spherical vesicle. However, a difference in the composition of the two leaflets may result in a curved bilayer or in a wide variety of vesicle shapes. Vesicles with different shapes have already been shown in experiments and diverse vesicle shapes have been predicted theoretically from energy minimization of continuous curves. Here we present a molecular dynamics study of the effect of small changes in the phospholipid headgroups on the spontaneous curvature of the bilayer and on the resulting vesicle shape transformations. Small asymmetries in the bilayers already result in high spontaneous curvature and large vesicle deformations. Vesicle shapes that are formed include ellipsoids, discoids, pear-shaped vesicles, cup-shaped vesicles, as well as budded vesicles. Comparison of these vesicles with theoretically derived vesicle shapes shows both resemblances and differences.
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Affiliation(s)
- A J Markvoort
- Department of Biomedical Engineering, TU Eindhoven, Postbus 513, 5600 MB Eindhoven, The Netherlands.
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Imbihl R, Scheibe A, Zeng YF, Günther S, Kraehnert R, Kondratenko VA, Baerns M, Offermans WK, Jansen APJ, van Santen RA. Catalytic ammonia oxidation on platinum: mechanism and catalyst restructuring at high and low pressure. Phys Chem Chem Phys 2007; 9:3522-40. [PMID: 17612719 DOI: 10.1039/b700866j] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Catalytic ammonia oxidation over platinum has been studied experimentally from UHV up to atmospheric pressure with polycrystalline Pt and with the Pt single crystal orientations (533), (443), (865), and (100). Density functional theory (DFT) calculations explored the reaction pathways on Pt(111) and Pt(211). It was shown, both in theory and experimentally, that ammonia is activated by adsorbed oxygen, i.e. by O(ad) or by OH(ad). In situ XPS up to 1 mbar showed the existence of NH(x)(x= 0,1,2,3) intermediates on Pt(533). Based on a mechanism of ammonia activation via the interaction with O(ad)/OH(ad) a detailed and a simplified mathematical model were formulated which reproduced the experimental data semiquantitatively. From transient experiments in vacuum performed in a transient analysis of products (TAP) reactor it was concluded that N(2)O is formed by recombination of two NO(ad) species and by a reaction between NO(ad) and NH(x,ad)(x= 0,1,2) fragments. Reaction-induced morphological changes were studied with polycrystalline Pt in the mbar range and with stepped Pt single crystals as model systems in the range 10(-5)-10(-1) mbar.
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Affiliation(s)
- R Imbihl
- Institut für Physikalische Chemie und Elektrochemie, Leibniz Universität Hannover, Callinstr. 3-3a, 30167, Hannover, Germany
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Hermse CGM, van Bavel AP, Nieuwenhuys BE, Lukkien JJ, van Santen RA, Jansen APJ. Lateral interactions and multi-isotherms: nitrogen recombination from Rh(111). Langmuir 2005; 21:8302-11. [PMID: 16114935 DOI: 10.1021/la050971y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Lateral adsorbate-adsorbate interactions result in variation of the desorption rate constants with coverage. This effect can be studied in great detail from the shape of a multi-isotherm. To produce the multi-isotherm, the temperature is increased in a (semi)stepwise fashion to some temperature, followed by maintaining this temperature for a prolonged time. Then, the temperature is stepped to a higher value and held constant at this new temperature. This cycle is continued until all of the adsorbates have desorbed. Using a detailed kinetic Monte Carlo model and an optimization algorithm based on Evolutionary Strategy, we are able to reproduce the shape of the experimentally measured multi-isotherm of nitrogen on Rh(111) and obtain the lateral interactions between the nitrogen atoms.
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Affiliation(s)
- C G M Hermse
- Schuit Institute of Catalysis, ST/SKA, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, The Netherlands.
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Kazansky VB, Subbotina IR, Rane N, van Santen RA, Hensen EJM. On two alternative mechanisms of ethane activation over ZSM-5 zeolite modified by Zn2+ and Ga1+ cations. Phys Chem Chem Phys 2005; 7:3088-92. [PMID: 16186914 DOI: 10.1039/b506782k] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The activation of ethane over zinc- and gallium-modified HZSM-5 dehydrogenation catalysts was studied by diffuse reflectance infrared spectroscopy. Hydrocarbon activation on HZSM-5 modified by bivalent Zn and univalent Ga cations proceeds via two distinctly different mechanisms. The stronger molecular adsorption of ethane by the acid-base pairs formed by distantly separated cationic Zn2+ and basic oxygen sites results already at room temperature in strong polarizability of adsorbed ethane and subsequent heterolytic dissociative adsorption at moderate temperatures. In contrast, molecular adsorption of ethane on Ga+ cations is weak. At high temperatures dissociative hydrocarbon adsorption takes place, resulting in the formation of ethyl and hydride fragments coordinating to the cationic gallium species. Whereas in the zinc case a Brønsted acid proton is formed upon ethane dissociation, decomposition of the ethyl fragment on gallium results in gallium dihydride species and does not lead to Brønsted acid protons. This difference in alkane activation has direct consequences for hydrocarbon conversions involving dehydrogenation.
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Affiliation(s)
- V B Kazansky
- Zelinsky Institute of Organic Chemistry, Leninsky Prospect 47, 119991 Moscow, Russia.
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Rozanska X, Barbosa LAMM, van Santen RA. A Periodic Density Functional Theory Study of Cumene Formation Catalyzed by H-Mordenite. J Phys Chem B 2004; 109:2203-11. [PMID: 16851212 DOI: 10.1021/jp049227x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A periodic density functional theory study of the alkylation of benzene with propene in proton-exchanged mordenite has been achieved. The two different reaction routes that are usually proposed for this reaction, namely the direct and the step-by-step reaction pathways, have been investigated. The explicit consideration of the zeolite catalyst framework allows a better level of description of the interactions between the catalyst framework and the reaction than what is obtained with the cluster approach method. The direct reaction route is found to be the preferred one. It is observed that the cluster approach method, which does not describe the zeolite framework, is unable to qualitatively described the trend in activation energies. This is owing to the greater stabilization of larger transition state by the mordenite zeolite framework compared with smaller ones.
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Affiliation(s)
- X Rozanska
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Technical University of Eindhoven, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands.
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Mihaleva VV, van Santen RA, Jansen APJ. Quantum chemical calculation of infrared spectra of acidic groups in chabazite in the presence of water. J Chem Phys 2004; 120:9212-21. [PMID: 15267858 DOI: 10.1063/1.1709896] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The changes in the spectra of the acidic group in chabazite are studied by quantum chemical calculations. The zeolite is modeled by two clusters consisting of eight tetrahedral atoms arranged in a ring and seven tetrahedral atoms coordinated around the zeolite OH group. The potential energy and dipole surfaces were constructed from the zeolite OH stretch, in-plane and out-of-plane bending coordinates, and the intermolecular stretch coordinate that corresponds to a movement of the water molecule as a whole. Both the anharmonicities of the potential energy and dipole were taken into account by calculation of the frequencies and intensities. The matrix elements of the vibrational Hamiltonian were calculated within the discrete variable representation basis set. We have assigned the experimentally observed frequencies at approximately 2900, approximately 2400, and approximately 1700 cm(-1) to the strongly perturbed zeolite OH vibrations caused by the hydrogen bonding with the water molecule. The ABC triplet is a Fermi resonance of the zeolite OH stretch mode with the overtone of the in-plane bending (the A band) and the overtone of the out-of-plane bending (the C band). In the B band the stretch is also coupled with the second overtone of the out-of-plane bending. The frequencies at approximately 3700 and approximately 3550 cm(-1) we have assigned to the OH stretch frequencies of a slightly perturbed water molecule.
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Affiliation(s)
- V V Mihaleva
- Schuit Institute of Catalysis, ST/SKA, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
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Feng Z, Liang C, Wu W, Wu Z, van Santen RA, Li C. Carbon Monoxide Adsorption on Molybdenum Phosphides: Fourier Transform Infrared Spectroscopic and Density Functional Theory Studies. J Phys Chem B 2003. [DOI: 10.1021/jp035351p] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhaochi Feng
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Changhai Liang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Weicheng Wu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Zili Wu
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - R. A. van Santen
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Can Li
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, China, and Schuit Institute of Cataysis, Eindhoven University of Technology, Eindhoven, The Netherlands
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Hermse CGM, Frechard F, van Bavel AP, Lukkien JJ, Niemantsverdriet JW, van Santen RA, Jansen APJ. Combining density-functional calculations with kinetic models: NO/Rh(111). J Chem Phys 2003. [DOI: 10.1063/1.1560139] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Affiliation(s)
- I. M. Ciobica
- Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - R. A. van Santen
- Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Lebedeva NP, Koper MTM, Feliu JM, van Santen RA. Role of Crystalline Defects in Electrocatalysis: Mechanism and Kinetics of CO Adlayer Oxidation on Stepped Platinum Electrodes. J Phys Chem B 2002. [DOI: 10.1021/jp0204105] [Citation(s) in RCA: 333] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. P. Lebedeva
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - M. T. M. Koper
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - J. M. Feliu
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - R. A. van Santen
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
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Lebedeva NP, Rodes A, Feliu JM, Koper MTM, van Santen RA. Role of Crystalline Defects in Electrocatalysis: CO Adsorption and Oxidation on Stepped Platinum Electrodes As Studied by in situ Infrared Spectroscopy. J Phys Chem B 2002. [DOI: 10.1021/jp0203806] [Citation(s) in RCA: 199] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. P. Lebedeva
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - A. Rodes
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - J. M. Feliu
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - M. T. M. Koper
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
| | - R. A. van Santen
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands, and Departamento de Quimica Fisica, Universidad de Alicante, Apartado 99, E-03080 Alicante, Spain
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Sobczy DP, van Grondelle J, de Jong AM, de Voigt MJA, van Santen RA. Production of chemically pure gaseous [13N]NH3 pulses for PEP studies using a modified DeVarda reduction. Appl Radiat Isot 2002; 57:201-7. [PMID: 12150279 DOI: 10.1016/s0969-8043(02)00094-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A fast and reproducible production method for pure gaseous [13N]NH3 pulses has been developed. 13N was produced by irradiation of water with 500 nA of 16 MeV protons via the 16O(p,alpha)13N reaction. A mixture of DeVarda's alloy and NaOH was used to convert the produced nitrate/nitrite to ammonia. Pre-treatment of this mixture with water increased the concentrated production of gaseous [13N]NH3. Separation and further purification of ammonia were performed with GC, leading to 5s pulses (1.1 ml STP) with 3.5 +/- 0.5 MBq [13N]NH3 with a high chemical and radiochemical purity suited for positron emission profiling (PEP).
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Affiliation(s)
- D P Sobczy
- Laboratory of Inorganic Chemistry and Catalysis, Schuit Institute of Catalysis, Eindhoven University of Technology, Netherlands.
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Zhu Q, Hensen EJM, Mojet BL, van Wolput JHMC, van Santen RA. N2O decomposition over Fe/ZSM-5: reversible generation of highly active cationic Fe species. Chem Commun (Camb) 2002:1232-3. [PMID: 12109097 DOI: 10.1039/b202843c] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fe-oxide species in Fe/ZSM-5 (prepared by chemical vapor deposition of FeCl3)--active in N2O decomposition--react with zeolite protons during high temperature calcination to give highly active cationic Fe species, this transformation being reversible upon exposure to water vapor at lower temperature.
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Affiliation(s)
- Q Zhu
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Affiliation(s)
- I. M. Ciobica
- Schuit Institute of Catalysis, Eindhoven University of Technology, SKA, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - R. A. van Santen
- Schuit Institute of Catalysis, Eindhoven University of Technology, SKA, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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Pelmenschikov AG, van Wolput JHMC, Jaenchen J, van Santen RA. (A,B,C) Triplet of Infrared OH Bands of Zeolitic H-Complexes. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100011a031] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Jacobs WPJH, de Haan JW, van de Ven LJM, van Santen RA. Interaction of ammonia with Broensted acid sites in different cages of zeolite Y as studied by proton MAS NMR. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100142a022] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Neurock M, van Santen RA, Biemolt W, Jansen APJ. Atomic and Molecular Oxygen as Chemical Precursors in the Oxidation of Ammonia by Copper. J Am Chem Soc 2002. [DOI: 10.1021/ja00094a046] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Teunissen EH, Jansen APJ, van Santen RA. Ab-Initio Embedded Cluster Study of the Adsorption of NH3 and NH4+ in Chabazite. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100007a014] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pelmenschikov AG, van Santen RA, Janchen J, Meijer E. Acetonitrile-d3 as a probe of Lewis and Broensted acidity of zeolites. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100144a028] [Citation(s) in RCA: 201] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Blaszkowski SR, van Santen RA. Density Functional Theory Calculations of the Activation of Methanol by a Broensted Zeolitic Proton. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100030a017] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Blaszkowski SR, Jansen APJ, Nascimento MAC, van Santen RA. Density Functional Theory Calculations of the Transition States for Hydrogen Exchange and Dehydrogenation of Methane by a Broensted Zeolitic Proton. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100100a021] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rozanska X, Demuth T, Hutschka F, Hafner J, van Santen RA. A Periodic Structure Density Functional Theory Study of Propylene Chemisorption in Acidic Chabazite: Effect of Zeolite Structure Relaxation. J Phys Chem B 2002. [DOI: 10.1021/jp011587m] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- X. Rozanska
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands, Institut für Materialphysik, Universität Wien, Sensengasse 8, A-1090 Wien, Austria, and TotalFinaElf, Département Chimie des Procédés, Centre Européen de Recherche et Technique, B.P. 27, F-76700 Harfleur, France
| | - Th. Demuth
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands, Institut für Materialphysik, Universität Wien, Sensengasse 8, A-1090 Wien, Austria, and TotalFinaElf, Département Chimie des Procédés, Centre Européen de Recherche et Technique, B.P. 27, F-76700 Harfleur, France
| | - F. Hutschka
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands, Institut für Materialphysik, Universität Wien, Sensengasse 8, A-1090 Wien, Austria, and TotalFinaElf, Département Chimie des Procédés, Centre Européen de Recherche et Technique, B.P. 27, F-76700 Harfleur, France
| | - J. Hafner
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands, Institut für Materialphysik, Universität Wien, Sensengasse 8, A-1090 Wien, Austria, and TotalFinaElf, Département Chimie des Procédés, Centre Européen de Recherche et Technique, B.P. 27, F-76700 Harfleur, France
| | - R. A. van Santen
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands, Institut für Materialphysik, Universität Wien, Sensengasse 8, A-1090 Wien, Austria, and TotalFinaElf, Département Chimie des Procédés, Centre Européen de Recherche et Technique, B.P. 27, F-76700 Harfleur, France
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Riedmüller B, Ciobı̂că IM, Papageorgopoulos DC, Frechard F, Berenbak B, Kleyn AW, van Santen RA. CO adsorption on hydrogen saturated Ru(0001). J Chem Phys 2001. [DOI: 10.1063/1.1395625] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Nienhuys HK, Planken PC, van Santen RA, Bakker HJ. Generation of mid-infrared pulses by X(3) difference frequency generation in CaF(2) and BaF(2). Opt Lett 2001; 26:1350-1352. [PMID: 18049605 DOI: 10.1364/ol.26.001350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Tunable mid-IR pulses in the range 1300-4200 cm(-1) (7.7-2.4 microm) are generated through a phase-matched four-wave mixing process in ordinary mid-IR window materials such as CaF(2) and BaF(2) . In this process the difference frequency v(3)=2v(2)-v(1) is generated from pump fields v(1) and v(2) . The process can be phase matched to different frequencies by adjustment of the angle between the pump fields.
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Mojet BL, Eckert J, van Santen RA, Albinati A, Lechner RE. Evidence for chemisorbed molecular hydrogen in Fe-ZSM5 from inelastic neutron scattering. J Am Chem Soc 2001; 123:8147-8. [PMID: 11506584 DOI: 10.1021/ja016078c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- B L Mojet
- Schuit Institute for Catalysis Eindhoven University of Technology, P.O. Box 513 NL-5600 MB Eindhoven, The Netherlands
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Rozanska X, van Santen RA, Hutschka F, Hafner J. A periodic DFT study of intramolecular isomerization reactions of toluene and xylenes catalyzed by acidic mordenite. J Am Chem Soc 2001; 123:7655-67. [PMID: 11480988 DOI: 10.1021/ja0103795] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A periodic density functional theory (DFT) study of the isomerization reactions of toluene and xylene catalyzed by acidic mordenite is reported. Monomolecular isomerization reactions have been considered and analyzed. The different reaction pathways have been discussed in detail. The use of periodic structure calculations allows consideration and analysis of zeolite electrostatic contributions and steric constraints that occur within zeolite micropores. Major differences in the details of protonation reaction pathways are found when periodic structures are used rather than small cluster models of the Brønsted acidic site. Complex relationships are found between zeolite topology and reaction pathways.
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Affiliation(s)
- X Rozanska
- Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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Hanssen RW, Meetsma A, van Santen RA, Abbenhuis HC. Synthesis, structural characterization, and transmetalation reactions of a tetranuclear magnesium silsesquioxane complex. Inorg Chem 2001; 40:4049-52. [PMID: 11466067 DOI: 10.1021/ic0004131] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of a silsesquioxane trisilanol with methylmagnesium chloride leads to an unprecedented tetranuclear magnesium silsesquioxane complex 1 in high yield. The crystal structure shows an unusually short Mg-Cl bond, indicative of an electron-deficient magnesium atom; 1 has been used as transmetalation agent for the synthesis of metal silsesquioxane complexes. Transmetalation activity was low, but can easily be followed by multinuclear NMR. Crystal data for 1: C(78)H(142)Cl(2)Mg(4)O(26)Si(14).6(C(4)H(8)O), a = 15.744(1) A, b = 26.526(2) A, c = 16.917(1) A, beta = 113.229(2) degrees, monoclinic, P2(1)/n, Z = 2.
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Affiliation(s)
- R W Hanssen
- Schuit Institute of Catalysis, Eindhoven University of Technology, PO Box 513, NL-5600 MB Eindhoven, The Netherlands
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Schuring D, Koriabkina AO, de Jong AM, Smit B, van Santen RA. Adsorption and Diffusion of n-Hexane/2-Methylpentane Mixtures in Zeolite Silicalite: Experiments and Modeling. J Phys Chem B 2001. [DOI: 10.1021/jp010158l] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- D. Schuring
- Laboratory of Inorganic Chemistry and Catalysis and Accelerator Laboratory, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - A. O. Koriabkina
- Laboratory of Inorganic Chemistry and Catalysis and Accelerator Laboratory, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - A. M. de Jong
- Laboratory of Inorganic Chemistry and Catalysis and Accelerator Laboratory, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - B. Smit
- Laboratory of Inorganic Chemistry and Catalysis and Accelerator Laboratory, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - R. A. van Santen
- Laboratory of Inorganic Chemistry and Catalysis and Accelerator Laboratory, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands, and Department of Chemical Engineering, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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Affiliation(s)
- V. V. Mihaleva
- Schuit Institute of Catalysis, ST/SKA Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
| | - R. A. van Santen
- Schuit Institute of Catalysis, ST/SKA Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
| | - A. P. J. Jansen
- Schuit Institute of Catalysis, ST/SKA Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, The Netherlands
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Abstract
The location of the Zn(2+) cation in Zn-exchanged chabazite has been studied by the periodical density functional method. Chabazite was chosen as a zeolite model, because it contains three different types of rings commonly found in the zeolite structures: four-, six-, and eight-membered rings. Two aluminum atoms have been employed to substitute the silicon atoms in the same D6R unit cell of the zeolite framework. This leads to different arrangements for the Brønsted site pair and the Zn(II) cation. The two Brønsted sites are found to be more stable when placed in the small ring (4T ring) than in the other rings. This suggests that the most reactive Brønsted sites are located in the large rings. Two Brønsted sites are most stable when the O(H)-Al-O-Si-O(H)-Al sequence is followed in the same ring instead of being located in two different rings. This resembles the aluminum distribution in the small four-membered ring and agrees with bond order conservation rules. The cation stability is markedly influenced by the distortions of the framework. Other factors that also contribute to the stabilization are the aluminum content near the cation and the stability of the original Brønsted sites. The Zn(2+) cation is more stable in the large rings than in the small ones, the six-membered one being the most stable configuration. In the small rings, the cation is, therefore, more reactive. Two different probe molecules have been used to study the interaction with the Zn(II) cation: water and methane. These probe molecules can extract the active center from its original position. For the water molecule, this effect is large and leads to a high framework relaxation. The value of the binding energy of this molecule to the active sites is influenced by these framework relaxations as well as by the cationic position environment. For weakly interacting methane, these effects are significantly less.
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Affiliation(s)
- L A Barbosa
- Schuit Institute of Catalysis, Eindhoven University of Technology, The Netherlands.
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