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Liao GJ, Hsueh WH, Yen YH, Shih YC, Wang CH, Wang JH, Luo MF. Decomposition of methanol-d 4 on Rh nanoclusters supported by thin-film Al 2O 3/NiAl(100) under near-ambient-pressure conditions. Phys Chem Chem Phys 2024; 26:5059-5069. [PMID: 38258542 DOI: 10.1039/d3cp05303b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The decomposition of methanol-d4 (CD3OD) on Rh nanoclusters grown by the deposition of Rh vapors onto an ordered thin film of Al2O3/NiAl(100) was studied, with various surface-probe techniques and largely under near-ambient-pressure (NAP) conditions. The results showed a superior reactivity of small Rh clusters (diameter < 1.5 nm) exposed to CD3OD at 5 × 10-3-0.1 mbar at 400 K; the gaseous production of CO and D2 from decomposed methanol-d4 per Rh surface site on the small Rh clusters with diameters of ∼1.1 nm was nearly 8 times that on large ones with diameters of ∼3.5 nm. The promotion of reactivity with decreased cluster size under NAP conditions was evidently greater than that under ultrahigh vacuum conditions. Moreover, the concentration of atomic carbon (C*; where * denotes adsorbate)-a key catalyst poisoner-yielded from the dissociation of CO* from dehydrogenated methanol-d4 was significantly smaller on small clusters (diameter < 1.5 nm). The NAP size effect on methanol-d4 decomposition involved the surface hydroxyl (OH*) from the little co-adsorbed water (H2O*) that was dissociated at a probability dependent on the cluster size. H2O* was more likely dissociated into OH* on small Rh clusters, by virtue of their more reactive d-band structure, and the OH* then effectively promoted the O-D cleavage of methanol-d4, as the rate-determining step, and thus the reaction probability; on the other hand, the OH* limited CO* dissociation on small Rh clusters via both adsorbate and lateral effects. These results suggest that the superior properties of small Rh clusters in both reactivity and anti-poisoning would persist and be highly applicable under "real-world" catalysis conditions.
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Affiliation(s)
- Guan-Jr Liao
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan.
| | - Wen-Hao Hsueh
- Department of Chemistry, National Taiwan Normal University, No. 88, Section 4, Ting-Zhou Road, Taipei, Taiwan.
| | - Yu-Hsiang Yen
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan.
| | - Yi-Chan Shih
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan.
| | - Chia-Hsin Wang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Jeng-Han Wang
- Department of Chemistry, National Taiwan Normal University, No. 88, Section 4, Ting-Zhou Road, Taipei, Taiwan.
| | - Meng-Fan Luo
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan.
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2
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Liao GJ, Hsueh WH, Yen YH, Shih YC, Wang CH, Wang JH, Luo MF. Decomposition of methanol-d4 on a thin film of Al2O3/NiAl(100) under near-ambient-pressure conditions. J Chem Phys 2023; 158:2887766. [PMID: 37129140 DOI: 10.1063/5.0151135] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 04/17/2023] [Indexed: 05/03/2023] Open
Abstract
We have studied the decomposition of methanol-d4 on thin film Al2O3/NiAl(100) under near-ambient-pressure conditions, with varied surface-probe techniques and calculations based on density-functional theory. Methanol-d4 neither adsorbed nor reacted on Al2O3/NiAl(100) at 400 K under ultrahigh vacuum conditions, whereas they dehydrogenated, largely to methoxy-d3 (CD3O*, * denoting adsorbates) and formaldehyde-d2 (CD2O*), on the surface when the methanol-d4 partial pressure was increased to 10-3 mbar and above. The dehydrogenation was facilitated by hydroxyl (OH* or OD*) from the dissociation of little co-adsorbed water; a small fraction of CD2O* interacted further with OH* (OD*) to form, via intermediate CD2OOH* (CD2OOD*), formic acid (DCOOH* or DCOOD*). A few surface carbonates were also yielded, likely on the defect sites of Al2O3/NiAl(100). The results suggest that alumina not only supports metal clusters but also participates in reactions under realistic catalytic conditions. One may consider accordingly the multiple functions of alumina while designing ideal catalysts.
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Affiliation(s)
- Guan-Jr Liao
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Wen-Hao Hsueh
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei, Taiwan
| | - Yu-Hsiang Yen
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Yi-Chan Shih
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
| | - Chia-Hsin Wang
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Jeng-Han Wang
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei, Taiwan
| | - Meng-Fan Luo
- Department of Physics, National Central University, No. 300 Jhongda Road, Jhongli 32054, Taiwan
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3
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Salman MS, Rambhujun N, Pratthana C, Srivastava K, Aguey-Zinsou KF. Catalysis in Liquid Organic Hydrogen Storage: Recent Advances, Challenges, and Perspectives. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.1c03970] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Muhammad Saad Salman
- MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Nigel Rambhujun
- MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Chulaluck Pratthana
- MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Kshitij Srivastava
- MERLin, School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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4
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Model Catalysis with HOPG-Supported Pd Nanoparticles and Pd Foil: XPS, STM and C2H4 Hydrogenation. Catal Letters 2021; 152:2892-2907. [PMID: 36196216 PMCID: PMC9525433 DOI: 10.1007/s10562-021-03868-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/15/2021] [Indexed: 11/17/2022]
Abstract
A surface science based approach was applied to model carbon supported Pd nanoparticle catalysts. Employing physical vapour deposition of Pd on sputtered surfaces of highly oriented pyrolytic graphite (HOPG), model catalysts were prepared that are well-suited for characterization by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). Analysis of the HOPG substrate before and after ion-bombardment, and of Pd/HOPG before and after annealing, revealed the number of “nominal” HOPG defects (~ 1014 cm−2) as well as the nucleation density (~ 1012 cm−2) and structural characteristics of the Pd nanoparticles (mean size/height/distribution). Two model systems were stabilized by UHV annealing to 300 °C, with mean Pd particles sizes of 4.3 and 6.8 nm and size/height aspect ratio up to ~ 10. A UHV-compatible flow microreactor and gas chromatography were used to determine the catalytic performance of Pd/HOPG in ethylene (C2H4) hydrogenation up to 150 °C under atmospheric pressure, yielding temperature-dependent conversion values, turnover frequencies (TOFs) and activation energies. The performance of Pd nanocatalysts is compared to that of polycrystalline Pd foil and contrasted to Pt/HOPG and Pt foil, pointing to a beneficial effect of the metal/carbon phase boundary, reflected by up to 10 kJ mol−1 lower activation energies for supported nanoparticles.
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Golder KM, Böller B, Stienen G, Sickerling J, Wintterlin J. A highly sensitive gas chromatograph for in situ and operando experiments on catalytic reactions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:124103. [PMID: 34972407 DOI: 10.1063/5.0068021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 11/20/2021] [Indexed: 06/14/2023]
Abstract
We describe an automated gas sampling and injection unit for a gas chromatograph (GC). It has specially been designed for low concentrations of products formed in catalytic in situ and operando experiments when slow reactions on single crystal models are investigated. The unit makes use of a buffer volume that is filled with gas samples from the reactor at a reduced pressure. The gas samples are then compressed by He to the injection pressure of 1000 mbar and pushed into two sample loops of the GC, without major intermixing with He. With an additional cryo trap at one of the GC column heads, the design aims at concentrating the gas samples and focusing the peaks. The performance is characterized by experiments on the Fischer-Tropsch synthesis, using H2/CO mixtures (syngas) at 200 and 950 mbar and a Co(0001) single crystal sample as model catalyst. Chromatograms recorded during the reaction display sharp, well separated peaks of saturated and unsaturated C1 to C4 hydrocarbons formed by the reaction, whereas the syngas matrix only gives moderate signals that can be well separated from the product peaks. Detection and quantification limits of 0.4 and 1.3 ppb, respectively, have been achieved and turnover numbers as low as 10-5 s-1 could be measured. The system can be combined with all known analysis techniques used in in situ and operando experiments.
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Affiliation(s)
- Katharina M Golder
- Department Chemie, Ludwig-Maximilians-Universität München, 80377 Munich, Germany
| | - Bernhard Böller
- Department Chemie, Ludwig-Maximilians-Universität München, 80377 Munich, Germany
| | | | | | - Joost Wintterlin
- Department Chemie, Ludwig-Maximilians-Universität München, 80377 Munich, Germany
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6
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Sangkhun W, Wanwong S, Wootthikanokkhan J, Sinthiptharakoon K, Kumnorkaew P. Enhanced Water Splitting Reaction Performance using TiO
2
Deposited with Graphene Quantum Dots Grafted onto Gold Nanoparticles. ChemistrySelect 2021. [DOI: 10.1002/slct.202101445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Weradesh Sangkhun
- Materials Technology Program School of Energy Environment and Materials King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Rd., Bang Mod Thung Khru Bangkok 10140 Thailand
| | - Sompit Wanwong
- Materials Technology Program School of Energy Environment and Materials King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Rd., Bang Mod Thung Khru Bangkok 10140 Thailand
| | - Jatuphorn Wootthikanokkhan
- Materials Technology Program School of Energy Environment and Materials King Mongkut's University of Technology Thonburi (KMUTT) 126 Pracha Uthit Rd., Bang Mod Thung Khru Bangkok 10140 Thailand
| | - Kitiphat Sinthiptharakoon
- National Nanotechnology Center (NANOTEC) National Science and Technology Development Agency (NSTDA) 111 Thailand Science Park Pathum Thani 12120 Thailand
| | - Pisist Kumnorkaew
- National Nanotechnology Center (NANOTEC) National Science and Technology Development Agency (NSTDA) 111 Thailand Science Park Pathum Thani 12120 Thailand
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7
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Kersell H, Chen P, Martins H, Lu Q, Brausse F, Liu BH, Blum M, Roy S, Rude B, Kilcoyne A, Bluhm H, Nemšák S. Simultaneous ambient pressure x-ray photoelectron spectroscopy and grazing incidence x-ray scattering in gas environments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:044102. [PMID: 34243438 DOI: 10.1063/5.0044162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
We have developed an experimental system to simultaneously measure surface structure, morphology, composition, chemical state, and chemical activity for samples in gas phase environments. This is accomplished by simultaneously measuring x-ray photoelectron spectroscopy (XPS) and grazing incidence x-ray scattering in gas pressures as high as the multi-Torr regime while also recording mass spectrometry. Scattering patterns reflect near-surface sample structures from the nano-scale to the meso-scale, and the grazing incidence geometry provides tunable depth sensitivity of structural measurements. Scattered x rays are detected across a broad range of angles using a newly designed pivoting-UHV-manipulator for detector positioning. At the same time, XPS and mass spectrometry can be measured, all from the same sample spot and under ambient conditions. To demonstrate the capabilities of this system, we measured the chemical state, composition, and structure of Ag-behenate on a Si(001) wafer in vacuum and in O2 atmosphere at various temperatures. These simultaneous structural, chemical, and gas phase product probes enable detailed insights into the interplay between the structure and chemical state for samples in gas phase environments. The compact size of our pivoting-UHV-manipulator makes it possible to retrofit this technique into existing spectroscopic instruments installed at synchrotron beamlines. Because many synchrotron facilities are planning or undergoing upgrades to diffraction limited storage rings with transversely coherent beams, a newly emerging set of coherent x-ray scattering experiments can greatly benefit from the concepts we present here.
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Affiliation(s)
- Heath Kersell
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Pengyuan Chen
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720, USA
| | - Henrique Martins
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Qiyang Lu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Felix Brausse
- Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Bo-Hong Liu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Monika Blum
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Sujoy Roy
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Bruce Rude
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Arthur Kilcoyne
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Hendrik Bluhm
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Slavomír Nemšák
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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8
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Liao GJ, Liu KT, Liao ZH, Hsu PW, Wang JH, Luo MF. Dependence on Size of Supported Rh Nanoclusters in the Dehydrogenation of Methanol- d4 Obstructed by CO. J Phys Chem Lett 2021; 12:2622-2629. [PMID: 33719453 DOI: 10.1021/acs.jpclett.1c00634] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The size effect on the activity of a catalyst has been a focal issue since ideal catalysts were pursued, whereas that on the degradation of a catalyst, by reaction intermediates such as CO, is little discussed. We demonstrate that the dehydrogenation of methanol-d4 on supported Rh nanoclusters precovered with CO (Rh-CO clusters) was obstructed, indicated by a decreased production of CO and D2; the obstructive effect exhibits a remarkable dependence on the cluster size, with a minimum at a cluster diameter near 1.4 nm. The decreased production arose from a decreased reaction probability controlled by the increased activation energy for each dehydrogenation step (including formation of methoxy-d3), adsorption energies of CO, and repulsion from the CO array on the Rh-CO surface. The effects of these factors in deactivating the clusters varied separately with the cluster size. Consequently, the size effect on the CO poisoning should be taken into account in engineering the cluster size to optimize the catalytic performance.
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Affiliation(s)
- Guan-Jr Liao
- Department of Physics, National Central University, 300 Jhongda Road, Jhongli District, Taoyuan 32001, Taiwan
| | - Kuan-Ting Liu
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei 11677, Taiwan
| | - Zhen-He Liao
- Department of Physics, National Central University, 300 Jhongda Road, Jhongli District, Taoyuan 32001, Taiwan
| | - Po-Wei Hsu
- Department of Physics, National Central University, 300 Jhongda Road, Jhongli District, Taoyuan 32001, Taiwan
| | - Jeng-Han Wang
- Department of Chemistry, National Taiwan Normal University, No. 88, Sec. 4, Ting-Zhou Road, Taipei 11677, Taiwan
| | - Meng-Fan Luo
- Department of Physics, National Central University, 300 Jhongda Road, Jhongli District, Taoyuan 32001, Taiwan
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Schuster R, Bertram M, Runge H, Geile S, Chung S, Vonk V, Noei H, Poulain A, Lykhach Y, Stierle A, Libuda J. Metastability of palladium carbide nanoparticles during hydrogen release from liquid organic hydrogen carriers. Phys Chem Chem Phys 2021; 23:1371-1380. [PMID: 33393575 DOI: 10.1039/d0cp05606e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Efficient hydrogen release from liquid organic hydrogen carriers (LOHCs) requires a high level of control over the catalytic properties of supported noble metal nanoparticles. Here, the formation of carbon-containing phases under operation conditions has a direct influence on the activity and selectivity of the catalyst. We studied the formation and stability of carbide phases using well-defined Pd/α-Al2O3(0001) model catalysts during dehydrogenation of a model LOHC, methylcyclohexane, in a flow reactor by in situ high-energy grazing incidence X-ray diffraction. The phase composition of supported Pd nanoparticles was investigated as a function of particle size and reaction conditions. Under operating conditions, we detected the formation of a PdxC phase followed by its conversion to Pd6C. The dynamic stability of the Pd6C phase results from the balance between uptake and release of carbon by the supported Pd nanoparticles in combination with the thermodynamically favorable growth of carbon deposits in the form of graphene. For small Pd nanoparticles (6 nm), the Pd6C phase is dynamically stable under low flow rate of reactants. At the high reactant flow, the Pd6C phase decomposes shortly after its formation due to the growth of graphene. Structural analysis of larger Pd nanoparticles (15 nm) reveals the formation and simultaneous presence of two types of carbides, PdxC and Pd6C. Formation and decomposition of Pd6C proceeds via a PdxC phase. After an incubation period, growth of graphene triggers the decomposition of carbides. The process is accompanied by segregation of carbon from the bulk of the nanoparticles to the graphene phase. Notably, nucleation of graphene is more favorable on bigger Pd nanoparticles. Our studies demonstrate that metastability of palladium carbides associated with dynamic formation and decomposition of the Pd6C and PdxC phases is an intrinsic phenomenon in LOHC dehydrogenation on Pd-based catalysts and strongly depends on particle size and reaction conditions.
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Affiliation(s)
- Ralf Schuster
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.
| | - Manon Bertram
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.
| | - Henning Runge
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany and Fachbereich Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany
| | - Simon Geile
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Simon Chung
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Vedran Vonk
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Heshmat Noei
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Agnieszka Poulain
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Yaroslava Lykhach
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.
| | - Andreas Stierle
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany and Fachbereich Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany
| | - Jörg Libuda
- Interface Research and Catalysis, ECRC, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany.
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Roiaz M, Pramhaas V, Li X, Rameshan C, Rupprechter G. Atmospheric pressure reaction cell for operando sum frequency generation spectroscopy of ultrahigh vacuum grown model catalysts. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:045104. [PMID: 29716385 DOI: 10.1063/1.5021641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A new custom-designed ultrahigh vacuum (UHV) chamber coupled to a UHV and atmospheric-pressure-compatible spectroscopic and catalytic reaction cell is described, which allows us to perform IR-vis sum frequency generation (SFG) vibrational spectroscopy during catalytic (kinetic) measurements. SFG spectroscopy is an exceptional tool to study vibrational properties of surface adsorbates under operando conditions, close to those of technical catalysis. This versatile setup allows performing surface science, SFG spectroscopy, catalysis, and electrochemical investigations on model systems, including single crystals, thin films, and deposited metal nanoparticles, under well-controlled conditions of gas composition, pressure, temperature, and potential. The UHV chamber enables us to prepare the model catalysts and to analyze their surface structure and composition by low energy electron diffraction and Auger electron spectroscopy, respectively. Thereafter, a sample transfer mechanism moves samples under UHV to the spectroscopic cell, avoiding air exposure. In the catalytic cell, SFG spectroscopy and catalytic tests (reactant/product analysis by mass spectrometry or gas chromatography) are performed simultaneously. A dedicated sample manipulation stage allows the model catalysts to be examined from LN2 temperature to 1273 K, with gaseous reactants in a pressure range from UHV to atmospheric. For post-reaction analysis, the SFG cell is rapidly evacuated and samples are transferred back to the UHV chamber. The capabilities of this new setup are demonstrated by benchmark results of CO adsorption on Pt and Pd(111) single crystal surfaces and of CO adsorption and oxidation on a ZrO2 supported Pt nanoparticle model catalyst grown by atomic layer deposition.
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Affiliation(s)
- Matteo Roiaz
- Institute of Materials Chemistry, Technische Universität Wien, Vienna 1060, Austria
| | - Verena Pramhaas
- Institute of Materials Chemistry, Technische Universität Wien, Vienna 1060, Austria
| | - Xia Li
- Institute of Materials Chemistry, Technische Universität Wien, Vienna 1060, Austria
| | - Christoph Rameshan
- Institute of Materials Chemistry, Technische Universität Wien, Vienna 1060, Austria
| | - Günther Rupprechter
- Institute of Materials Chemistry, Technische Universität Wien, Vienna 1060, Austria
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11
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Nguyen L, Tao FF. Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:024102. [PMID: 29495804 DOI: 10.1063/1.5003184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.
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Affiliation(s)
- Luan Nguyen
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045, USA
| | - Franklin Feng Tao
- Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045, USA
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12
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Ou L. New Insights into the Pt-Catalyzed CH 3OH Oxidation Mechanism: First-Principle Considerations on Thermodynamics, Kinetics, and Reversible Potentials. ACS OMEGA 2018; 3:886-897. [PMID: 31457935 PMCID: PMC6641505 DOI: 10.1021/acsomega.7b01725] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 01/03/2018] [Indexed: 06/10/2023]
Abstract
A systematic first-principle study of CH3OH oxidation along indirect and direct pathways on Pt(111) has been carried out, and some new insights into CH3OH oxidation pathways in direct CH3OH fuel cells (DMFCs) are presented. The thermodynamics, kinetics, and reversible potentials for all possible elementary steps, initializing with C-H, O-H, and C-O bond cleavages and proceeding via sequential decomposition and oxidation from the reaction intermediates, are analyzed. Some key reactive intermediates are identified. By comparing the activation energies and reversible potentials of various possible elementary reaction steps, we can speculate that the initial CH3OH oxidation step proceeds by the CH3O intermediate under a nonelectrochemical environment, whereas it prefers to occur by the CH2OH intermediate under electrochemical environment. Furthermore, CHO hydroxylation into HCOOH along a direct pathway is more facile to occur than CHO dehydrogenation into CO along an indirect pathway at the nonelectrochemical interface, whereas the indirect and direct pathways may be parallel pathways on Pt(111) under the present simulated electrochemical environment. Simultaneously, CH3 can be easily formed through C-O bond cleavage in CH3OH, which is a nonelectrochemical step. Thus, the CH x (x = 0-3) species is possibly formed on Pt(111) during CH3OH oxidation regardless of being under an electrochemical or nonelectrochemical environment. The adsorbed CH x species will result in the blocking of the active sites and the prevention of further CH3OH oxidation. Our present findings on the formation of carbonaceous deposits on Pt(111) are consistent with the experimentally observed C-O bond scission of CH3OH into CH x species. Thus, we propose that the adsorbed residues that poisoned the Pt surface and impeded the performance of DMFCs may be CH x species, rather than CO species, since the direct pathway is more favorable on Pt(111) at the nonelectrochemical interface. However, the poisonous species that occupied the active sites of the Pt surface may be CH x and CO species due to the simultaneous occurrence of oxidation pathways on Pt(111) under the present simulated electrochemical environment. Based on the present study, some new insights into CH3OH oxidation mechanisms and designing strategies of Pt-based alloy catalysts for CH3OH oxidation can be provided.
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Affiliation(s)
- Lihui Ou
- College
of Chemistry and Materials Engineering, Hunan University of Arts and Science, Changde 415000, China
- Hunan
Province Cooperative Innovation Center for the Construction &
Development of Dongting Lake Ecologic Economic Zone, Hunan University of Arts and Science, Changde 415000, China
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13
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Roy K, Artiglia L, van Bokhoven JA. Ambient Pressure Photoelectron Spectroscopy: Opportunities in Catalysis from Solids to Liquids and Introducing Time Resolution. ChemCatChem 2018. [DOI: 10.1002/cctc.201701522] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kanak Roy
- Institute for Chemical and Bioengineering; ETH Zürich; Zürich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
| | - Luca Artiglia
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
| | - Jeroen A. van Bokhoven
- Institute for Chemical and Bioengineering; ETH Zürich; Zürich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry; Paul Scherrer Institute; Villigen Switzerland
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14
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Eremin DB, Ananikov VP. Understanding active species in catalytic transformations: From molecular catalysis to nanoparticles, leaching, “Cocktails” of catalysts and dynamic systems. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2016.12.021] [Citation(s) in RCA: 243] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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16
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Hung TC, Liao TW, Liao ZH, Hsu PW, Cai PY, Lee H, Lai YL, Hsu YJ, Chen HY, Wang JH, Luo MF. Dependence on Size of Supported Rh Nanoclusters in the Decomposition of Methanol. ACS Catal 2015. [DOI: 10.1021/acscatal.5b00579] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ting-Chieh Hung
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Ting-Wei Liao
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Zhen-He Liao
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Po-Wei Hsu
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Pei-Yang Cai
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Hsuan Lee
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
| | - Yu-Ling Lai
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science
Park, Hsinchu 30076, Taiwan
| | - Yao-Jane Hsu
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science
Park, Hsinchu 30076, Taiwan
| | - Hui-Yu Chen
- Department
of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Jeng-Han Wang
- Department
of Chemistry, National Taiwan Normal University, Taipei, Taiwan
| | - Meng-Fan Luo
- Department
of Physics, National Central University, 300 Jhongda Road, Jhongli 32001, Taiwan
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17
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Oxidation of propylene over Pd(551): Temperature hysteresis induced by carbon deposition and oxygen adsorption. Catal Today 2015. [DOI: 10.1016/j.cattod.2014.08.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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18
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Kaichev VV, Prosvirin IP, Bukhtiyarov VI. Decomposition and oxidation of methanol on platinum: A study by in situ X-ray photoelectron spectroscopy and mass spectrometry. KINETICS AND CATALYSIS 2014. [DOI: 10.1134/s0023158414040065] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Holzapfel HH, Wolfbeisser A, Rameshan C, Weilach C, Rupprechter G. PdZn Surface Alloys as Models of Methanol Steam Reforming Catalysts: Molecular Studies by LEED, XPS, TPD and PM-IRAS. Top Catal 2014. [DOI: 10.1007/s11244-014-0295-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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21
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Zhang C, Myers J, Chen Z. Elucidation of molecular structures at buried polymer interfaces and biological interfaces using sum frequency generation vibrational spectroscopy. SOFT MATTER 2013; 9:4738-4761. [PMID: 23710244 PMCID: PMC3661304 DOI: 10.1039/c3sm27710k] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy has been developed into an important technique to study surfaces and interfaces. It can probe buried interfaces in situ and provide molecular level structural information such as the presence of various chemical moieties, quantitative molecular functional group orientation, and time dependent kinetics or dynamics at such interfaces. This paper focuses on these three most important advantages of SFG and reviews some of the recent progress in SFG studies on interfaces related to polymer materials and biomolecules. The results discussed here demonstrate that SFG can provide important molecular structural information of buried interfaces in situ and in real time, which is difficult to obtain by other surface sensitive analytical techniques.
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Affiliation(s)
- Chi Zhang
- Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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22
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Haghofer A, Ferri D, Föttinger K, Rupprechter G. Who Is Doing the Job? Unraveling the Role of Ga2O3 in Methanol Steam Reforming on Pd2Ga/Ga2O3. ACS Catal 2012. [DOI: 10.1021/cs300480c] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Andreas Haghofer
- Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/BC,
A-1060 Vienna, Austria
| | - Davide Ferri
- Empa, Swiss Federal Laboratories for Material Science and Technology, Laboratory
for Solid State Chemistry and Catalysis, Ueberlandstr. 129, CH-8600
Dübendorf, Switzerland
| | - Karin Föttinger
- Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/BC,
A-1060 Vienna, Austria
| | - Günther Rupprechter
- Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/BC,
A-1060 Vienna, Austria
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23
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Kaichev VV, Prosvirin IP, Bukhtiyarov VI. XPS for in situ study of the mechanisms of heterogeneous catalytic reactions. J STRUCT CHEM+ 2012. [DOI: 10.1134/s0022476611070134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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24
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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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25
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Theoretical study on the effective methanol decomposition on Pd(111) surface facilitated in alkaline medium. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2011.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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26
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Alov NV. Development of methods of surface analysis in Russia. JOURNAL OF ANALYTICAL CHEMISTRY 2011. [DOI: 10.1134/s1061934811110025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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28
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Hu GR, Chao CS, Shiu HW, Wang CT, Lin WR, Hsu YJ, Luo MF. Low-temperature decomposition of methanol on Au nanoclusters supported on a thin film of Al2O3/NiAl(100). Phys Chem Chem Phys 2011; 13:3281-90. [DOI: 10.1039/c0cp00526f] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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29
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Nasluzov VA, Ivanova-Shor EA, Shor AM, Yudanov IV, Rösch N. Simulation of heterogeneous catalysts and catalytic processes using the density functional method. KINETICS AND CATALYSIS 2010. [DOI: 10.1134/s0023158410060091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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30
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Qi X, Wei Z, Li L, Li L, Ji M, Zhang Y, Xia M, Ma X. DFT studies of the pH dependence of the reactivity of methanol on a Pd(111) surface. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.07.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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31
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Yudanov IV, Neyman KM. Stabilization of Au at edges of bimetallic PdAu nanocrystallites. Phys Chem Chem Phys 2010; 12:5094-100. [DOI: 10.1039/b927048e] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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33
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Kozlov SM, Yudanov IV, Aleksandrov HA, Rösch N. Theoretical study of carbon species on Pd(111): competition between migration of C atoms to the subsurface interlayer and formation of Cn clusters on the surface. Phys Chem Chem Phys 2009; 11:10955-63. [DOI: 10.1039/b916855a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Knop‐Gericke A, Kleimenov E, Hävecker M, Blume R, Teschner D, Zafeiratos S, Schlögl R, Bukhtiyarov VI, Kaichev VV, Prosvirin IP, Nizovskii AI, Bluhm H, Barinov A, Dudin P, Kiskinova M. Chapter 4 X‐Ray Photoelectron Spectroscopy for Investigation of Heterogeneous Catalytic Processes. ADVANCES IN CATALYSIS 2009. [DOI: 10.1016/s0360-0564(08)00004-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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35
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Yudanov IV, Matveev AV, Neyman KM, Rösch N. How the C−O Bond Breaks during Methanol Decomposition on Nanocrystallites of Palladium Catalysts. J Am Chem Soc 2008; 130:9342-52. [DOI: 10.1021/ja078322r] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ilya V. Yudanov
- Department Chemie, Theoretische Chemie, Technische Universität München, 85747 Garching, Germany, Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, IQTCUB & Departament de Química Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Alexei V. Matveev
- Department Chemie, Theoretische Chemie, Technische Universität München, 85747 Garching, Germany, Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, IQTCUB & Departament de Química Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Konstantin M. Neyman
- Department Chemie, Theoretische Chemie, Technische Universität München, 85747 Garching, Germany, Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, IQTCUB & Departament de Química Física, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Notker Rösch
- Department Chemie, Theoretische Chemie, Technische Universität München, 85747 Garching, Germany, Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, IQTCUB & Departament de Química Física, Universitat de Barcelona, 08028 Barcelona, Spain
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36
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Viñes F, Illas F, Neyman KM. Density Functional Calculations of Pd Nanoparticles Using a Plane-Wave Method. J Phys Chem A 2008; 112:8911-5. [DOI: 10.1021/jp8014854] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesc Viñes
- Departament de Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Francesc Illas
- Departament de Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Konstantin M. Neyman
- Departament de Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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37
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38
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Gabasch H, Knop-Gericke A, Schlögl R, Unterberger W, Hayek K, Klötzer B. Ethene Oxidation on Pd(111): Kinetic Hysteresis Induced by Carbon Dissolution. Catal Letters 2007. [DOI: 10.1007/s10562-007-9227-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Gabasch H, Hayek K, Klötzer B, Knop-Gericke A, Schlögl R. Carbon incorporation in Pd(111) by adsorption and dehydrogenation of ethene. J Phys Chem B 2007; 110:4947-52. [PMID: 16526735 DOI: 10.1021/jp056765g] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The decomposition of ethene on the Pd(111) surface was studied at effective pressures in the 10(-8) to 10(-7) mbar range and at sample temperatures between 300 and 700 K, using an effusive capillary array beam doser for directional adsorption, LEED, AES, temperature programmed reaction, and TDS. In the temperature range of 350-440 K increasingly stronger dehydrogenation of the ethene molecule is observed. Whereas at 350 K an ethylidyne adlayer is still present after adsorption, already at temperatures around 440 K complete coverage of the surface by carbon is attained, while the bulk still retains the properties of pure Pd. Beyond 440 K a steady-state surface C coverage is established, which decreases with temperature and is determined by detailed balancing between the ethene gas-phase adsorption rate and the migration rate of carbon into the Pd bulk. This process gives rise to the formation of a "partially carbon-covered Pd(x)C(y) surface". Above 540 K the surface-bulk diffusion of adsorbed carbon becomes fast, and in the UHV experiment the ethene adsorption rate becomes limited by the ethene gas-phase supply. The carbon bulk migration rate and the steady-state carbon surface coverage were determined as a function of the sample temperature and the ethene flux. An activation energy of 107 kJ mol(-1) for the process of C diffusion from surface adsorption sites into the subsurface region was derived in the temperature range of 400-650 K by modeling the C surface coverage as a function of temperature on the basis of steady-state reaction kinetics, assuming a first-order process for C surface-subsurface diffusion and a second-order process for C(ads) formation by dissociative C2H4 adsorption.
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Affiliation(s)
- Harald Gabasch
- Institut für Physikalische Chemie, Universität Innsbruck, A-6020 Innsbruck, Austria
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40
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Silvestre-Albero J, Borasio M, Rupprechter G, Freund HJ. Combined UHV and ambient pressure studies of 1,3-butadiene adsorption and reaction on Pd(1 1 1) by GC, IRAS and XPS. CATAL COMMUN 2007. [DOI: 10.1016/j.catcom.2006.06.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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41
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Sum Frequency Generation and Polarization–Modulation Infrared Reflection Absorption Spectroscopy of Functioning Model Catalysts from Ultrahigh Vacuum to Ambient Pressure. ADVANCES IN CATALYSIS 2007. [DOI: 10.1016/s0360-0564(06)51004-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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42
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Bäumer M, Libuda J, Neyman KM, Rösch N, Rupprechter G, Freund HJ. Adsorption and reaction of methanol on supported palladium catalysts: microscopic-level studies from ultrahigh vacuum to ambient pressure conditions. Phys Chem Chem Phys 2007; 9:3541-58. [PMID: 17612720 DOI: 10.1039/b700365j] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We investigated the decomposition and (partial) oxidation of methanol on Pd based catalysts in an integrated attempt, simultaneously bridging both the pressure and the materials gap. Combined studies were performed on well-defined Pd model catalysts based on ordered Al(2)O(3) and Fe(3)O(4) thin films, on well-defined particles supported on powders and on Pd single crystals. The interaction of Pd nanoparticles and Pd(111) with CH(3)OH and CH(3)OH/O(2) mixtures was examined from ultrahigh vacuum conditions up to ambient pressures, utilizing a broad range of surface specific vibrational spectroscopies which included IRAS, TR-IRAS, PM-IRAS, SFG, and DRIFTS. Detailed kinetic studies in the low pressure region were performed by molecular beam methods, providing comprehensive insights into the microkinetics of the reaction system. The underlying microscopic processes were studied theoretically on the basis of specially designed 3-D nanocluster models containing approximately 10(2) metal atoms. The efficiency of this novel modelling approach was demonstrated by rationalizing and complementing pertinent experimental results. In order to connect these results to the behavior under ambient conditions, kinetic and spectroscopic investigations were performed in reaction cells and lab reactors. Specifically, we focused on (1) particle size and structure dependent effects in methanol oxidation and decomposition, (2) support effects and their relation to activity and selectivity, (3) the influence of poisons such as carbon, and (4) the role of oxide and surface oxide formation on Pd nanoparticles.
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Affiliation(s)
- Marcus Bäumer
- Institut für Angewandte und Physikalische Chemie, Universität Bremen, Leobener Str. NW2, D-28359, Bremen, Germany
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43
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Neyman KM, Lim KH, Chen ZX, Moskaleva LV, Bayer A, Reindl A, Borgmann D, Denecke R, Steinrück HP, Rösch N. Microscopic models of PdZn alloy catalysts: structure and reactivity in methanol decomposition. Phys Chem Chem Phys 2007; 9:3470-82. [PMID: 17612715 DOI: 10.1039/b700548b] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We review systematic experimental and theoretical efforts that explored formation, structure and reactivity of PdZn catalysts for methanol steam reforming, a material recently proposed to be superior to the industrially used Cu based catalysts. Experimentally, ordered surface alloys with a Pd : Zn ratio of approximately 1 : 1 were prepared by deposition of thin Zn layers on a Pd(111) surface and characterized by photoelectron spectroscopy and low-energy electron diffraction. The valence band spectrum of the PdZn alloy resembles closely the spectrum of Cu(111), in good agreement with the calculated density of states for a PdZn alloy of 1 : 1 stoichiometry. Among the issues studied with the help of density functional calculations are surface structure and stability of PdZn alloys and effects of Zn segregation in them, and the nature of the most likely water-related surface species present under the conditions of methanol steam reforming. Furthermore, a series of elementary reactions starting with the decomposition of methoxide, CH(3)O, along both C-H and C-O bond scission channels, on various surfaces of the 1 : 1 PdZn alloy [planar (111), (100) and stepped (221)] were quantified in detail thermodynamically and kinetically in comparison with the corresponding reactions on the surfaces Pd(111) and Cu(111). The overall surface reactivity of PdZn alloy was found to be similar to that of metallic Cu. Reactive methanol adsorption was also investigated by in situ X-ray photoelectron spectroscopy for pressures between 3 x 10(-8) and 0.3 mbar.
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Affiliation(s)
- Konstantin M Neyman
- Department Chemie, Technische Universität München, 85747, Garching, Germany.
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44
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Cañas-Ventura ME, Klappenberger F, Clair S, Pons S, Kern K, Brune H, Strunskus T, Wöll C, Fasel R, Barth JV. Coexistence of one- and two-dimensional supramolecular assemblies of terephthalic acid on Pd(111) due to self-limiting deprotonation. J Chem Phys 2006; 125:184710. [PMID: 17115782 DOI: 10.1063/1.2364478] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The adsorption of terephthalic acid [C(6)H(4)(COOH)(2), TPA] on a Pd(111) surface has been investigated by means of scanning tunneling microscopy (STM), x-ray photoelectron spectroscopy, and near-edge x-ray absorption fine structure spectroscopy under ultrahigh vacuum conditions at room temperature. We find the coexistence of one- (1D) and two-dimensional (2D) molecular ordering. Our analysis indicates that the 1D phase consists of intact TPA chains stabilized by a dimerization of the self-complementary carboxyl groups, whereas in the 2D phase, consisting of deprotonated entities, the molecules form lateral ionic hydrogen bonds. The supramolecular growth dynamics and the resulting structures are explained by a self-limiting deprotonation process mediated by the catalytic activity of the Pd surface. Our models for the molecular ordering are supported by molecular mechanics calculations and a simulation of high resolution STM images.
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Affiliation(s)
- M E Cañas-Ventura
- Institut de Physique des Nanostructures, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
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45
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Yudanov IV, Neyman KM, Rösch N. C–O bond scission of methoxide on Pd nanoparticles: A density functional study. Phys Chem Chem Phys 2006; 8:2396-401. [PMID: 16710487 DOI: 10.1039/b601695b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
C-O bond scission of methoxide species adsorbed at the surface of Pd nanoparticle was studied by DF calculations for the example of cuboctahedral Pd(79). To investigate different locations of adsorbed intermediates as well as the transition state of C-O bond scission, a substrate model was used, which allows one to consider adsorbates without any local geometry restrictions. In contrast to reaction sites on the flat Pd(111) surface and on extended facets, scission of the C-O bond of methoxide at cluster edges is exothermic by approximately 40 kJ mol(-1) and the decomposition product CH(3) is found to be stabilized there. However, the high calculated activation barrier, approximately 140 mol(-1), implies only a very slow reaction compared to dehydrogenation of CH(3)O.
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Affiliation(s)
- Ilya V Yudanov
- Department Chemie, Technische Universität München, Garching, Germany
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46
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Borasio M, Rodríguez de la Fuente O, Rupprechter G, Freund HJ. In Situ Studies of Methanol Decomposition and Oxidation on Pd(111) by PM-IRAS and XPS Spectroscopy. J Phys Chem B 2005; 109:17791-4. [PMID: 16853280 DOI: 10.1021/jp053855c] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Methanol decomposition and oxidation on Pd(111) at millibar pressure were studied by in situ polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS), on-line gas chromatography and pre- and postreaction X-ray photoelectron spectroscopy (XPS). Various dehydrogenation products such as methoxy CH3O, formaldehyde CH2O, formyl CHO, and CO could be spectroscopically identified. Methanol oxidation proceeds via dehydrogenation to formaldehyde CH2O, which either desorbs or is further dehydrogenated to CO, which is subsequently oxidized to CO2. Carbonaceous overlayers that are present during the reaction may favorably affect the selectivity toward CH2O. The reaction takes place on metallic Pd, and no indications of an involvement of Pd surface oxide were observed.
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Affiliation(s)
- Marta Borasio
- Fritz-Haber-Institut der MPG, Faradayweg 4-6, D-14195 Berlin, Germany
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47
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Kaichev VV, Bukhtiyarov VI, Rupprechter G, Freund HJ. Activation of the C-O bond on the surface of palladium: An In situ study by X-ray photoelectron spectroscopy and sum frequency generation. KINETICS AND CATALYSIS 2005. [DOI: 10.1007/s10975-005-0073-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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