1
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Fang YL, Zhao Z, Heck KN, Pretzer LA, Guo N, Wu T, Zhang W, Miller JT, Wong MS. Thermal annealing effects on palladium-decorated gold nanoparticle catalysts. J Catal 2022. [DOI: 10.1016/j.jcat.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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2
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Egle T, O'Connor CR, Friend CM. Regeneration of Active Surface Alloys during Cyclic Oxidation and Reduction: Oxidation of H 2 on Pd/Ag(111). J Phys Chem Lett 2021; 12:6752-6759. [PMID: 34264673 DOI: 10.1021/acs.jpclett.1c01367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The surface morphology and composition of a catalyst during excursions between oxidizing and reducing conditions can change substantially, especially in bimetallic alloys. Both thermodynamic and kinetic factors play a role in determining the properties of alloy surfaces where the active phase may be a metastable state. Previously, Ag oxide reduction was shown to be dramatically enhanced when Pd is on the surface; however, Pd is more stable when dissolved in Ag, raising the question as to whether a highly active Pd surface state will persist over multiple reaction cycles, a requirement for catalytic function. Experiments herein demonstrate that the enhanced chemical functionality due to the presence of Pd on the surface is retained, based on the enhanced rate of silver oxide reduction over multiple oxidation/reduction cycles for a Pd/Ag(111) model. Repeated oxidation and reduction promote PdAg alloying, and reversible structural and compositional changes are detected using X-ray photoelectron spectroscopy. This study establishes that metastable phases can persist in reactive processes on surfaces, indicating their potential in heterogeneous catalysis.
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3
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Sandu MP, Kovtunov MA, Baturin VS, Oganov AR, Kurzina IA. Influence of the Pd : Bi ratio on Pd-Bi/Al 2O 3 catalysts: structure, surface and activity in glucose oxidation. Phys Chem Chem Phys 2021; 23:14889-14897. [PMID: 34223584 DOI: 10.1039/d1cp01305j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Pd-Bi nanoparticles show high efficiency in catalyzing gluconic acid production by the glucose oxidation reaction. Although this type of catalyst was studied for some time, the correlation between bismuth content and catalytic activity is still unclear. Moreover, there is little information on the principles of the formation of Pd-Bi nanoparticles. In this work, the relation between bismuth content and the activity and selectivity of the PdxBiy/Al2O3 catalyst in the glucose oxidation process was studied. The catalytic samples were prepared by co-impregnation of the alumina support utilizing the metal-organic precursors of Pd and Bi. The samples obtained were tested in the glucose oxidation reaction and were studied by transmission electron microscopy (TEM), X-ray fluorescence analysis, X-ray photoelectron spectroscopy (XPS), and BET adsorption. It has been found that the Pd3 : Bi1 atomic ratio grants the highest catalytic efficiency for the studied samples. To explain this, we predicted stable Pd-Bi nanoparticles using ab initio evolutionary algorithm USPEX. The calculations demonstrate that nanoparticles tend to form Pd(core)-Bi(shell) structures turning to a crown-jewel morphology at lower Bi concentration, thus exposing the active Pd centers while maintaining the promoting effect of Bi.
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Affiliation(s)
- Mariya P Sandu
- National Research Tomsk State University, Prospekt Lenina, 36, 634050, Tomsk, Russia. and Siberian State Medical University, Moskovsky Tract, 2, 634050, Tomsk, Russia
| | - Mikhail A Kovtunov
- National Research Tomsk State University, Prospekt Lenina, 36, 634050, Tomsk, Russia.
| | - Vladimir S Baturin
- Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academy of Sciences, Kosygina, 19, Moscow, 119991, Russia and I. E. Tamm Theory Department, Lebedev Physical Institute, Russian Academy of Sciences, Leninskii Prospekt, 53, Moscow, 119991, Russia
| | - Artem R Oganov
- Skolkovo Institute of Science and Technology, Bolshoy Boulevard, 30, Building 1, 121205, Moscow, Russia
| | - Irina A Kurzina
- National Research Tomsk State University, Prospekt Lenina, 36, 634050, Tomsk, Russia.
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4
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Szilvási T, Yu H, Gold JI, Bao N, Wolter TJ, Twieg RJ, Abbott NL, Mavrikakis M. Coupling the chemical reactivity of bimetallic surfaces to the orientations of liquid crystals. MATERIALS HORIZONS 2021; 8:2050-2056. [PMID: 34846482 DOI: 10.1039/d1mh00035g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The development of responsive soft materials with tailored functional properties based on the chemical reactivity of atomically precise inorganic interfaces has not been widely explored. In this communication, guided by first-principles calculations, we design bimetallic surfaces comprised of atomically thin Pd layers deposited onto Au that anchor nematic liquid crystalline phases of 4'-n-pentyl-4-biphenylcarbonitrile (5CB) and demonstrate that the chemical reactivity of these bimetallic surfaces towards Cl2 gas can be tuned by specification of the composition of the surface alloy. Specifically, we use underpotential deposition to prepare submonolayer to multilayers of Pd on Au and employ X-ray photoelectron and infrared spectroscopy to validate computational predictions that binding of 5CB depends strongly on the Pd coverage, with ∼0.1 monolayer (ML) of Pd sufficient to cause the liquid crystal (LC) to adopt a perpendicular binding mode. Computed heats of dissociative adsorption of Cl2 on PdAu alloy surfaces predict displacement of 5CB from these surfaces, a result that is also confirmed by experiments revealing that 1 ppm Cl2 triggers orientational transitions of 5CB. By decreasing the coverage of Pd on Au from 1.8 ± 0.2 ML to 0.09 ± 0.02 ML, the dynamic response of 5CB to 1 ppm Cl2 is accelerated 3X. Overall, these results demonstrate the promise of hybrid designs of responsive materials based on atomically precise interfaces formed between hard bimetallic surfaces and soft matter.
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Affiliation(s)
- Tibor Szilvási
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706, USA.
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5
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Liang Y, Ma T, Xiong Y, Qiu L, Yu H, Liang F. Highly efficient blackberry-like trimetallic PdAuCu nanoparticles with optimized Pd content for ethanol electrooxidation. NANOSCALE 2021; 13:9960-9970. [PMID: 34018506 DOI: 10.1039/d1nr00841b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The rational design of highly efficient catalysts for ethanol electrooxidation is extremely challenging for developing direct ethanol fuel cells (DEFCs). Herein, a facile one-pot method has been developed to prepare blackberry-like PdAuCu nanoparticles (NPs) with tunable composition and surface structures. Among PdAuCu NPs with different Pd contents (1.6-22 mass%), PdAuCu NPs-0.5 (contained Pd at 2.5 mass%) delivered one of the highest catalytic activities of Pd-based catalysts towards ethanol electrooxidation, exhibiting a mass activity of 23.0 A mgPd-1. Kinetic analysis, electrochemical impedance spectroscopy and CO stripping test results suggested that the excellent electrocatalytic activity may originate from the optimized balance between Pd content and surface structure of PdAuCu NPs-0.5. The optimization of the balance between composition and surface structure would contribute to the further design of multimetallic nanoparticles for fuel cells and other applications.
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Affiliation(s)
- Yinyin Liang
- The State Key Laboratory of Refractories and Metallurgy, School of Chemistry and Chemical Engineering, Wuhan University of Science and Technology, Wuhan 430081, P. R. China.
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6
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Lu Y, Chen W, Wang Y, Huo F, Dong Y, Wei L, He H. Research Progress on the Preparation and Properties of Two Dimensional Structure of Ionic Liquids. ACTA CHIMICA SINICA 2021. [DOI: 10.6023/a20100475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Han S, Shin K, Henkelman G, Mullins CB. Selective Oxidation of Acetaldehyde to Acetic Acid on Pd–Au Bimetallic Model Catalysts. ACS Catal 2019. [DOI: 10.1021/acscatal.9b00079] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sungmin Han
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
| | - Kihyun Shin
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
- Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas 78712-0231, United States
| | - Graeme Henkelman
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
- Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas 78712-0231, United States
| | - C. Buddie Mullins
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
- McKetta Department of Chemical Engineering, Center for Nano and Molecular Science and Technology, Texas Materials Institute, Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
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8
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Evans EJ, Li H, Han S, Henkelman G, Mullins CB. Oxidative Cross-Esterification and Related Pathways of Co-Adsorbed Oxygen and Ethanol on Pd–Au. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04820] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Edward James Evans
- McKetta Department of Chemical Engineering and Department of Chemistry, Texas Materials Institute, Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
| | - Hao Li
- Department of Chemistry and the Institute for Computational and Engineering Sciences, Texas Materials Institute, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712, United States
| | - Sungmin Han
- McKetta Department of Chemical Engineering and Department of Chemistry, Texas Materials Institute, Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
| | - Graeme Henkelman
- Department of Chemistry and the Institute for Computational and Engineering Sciences, Texas Materials Institute, The University of Texas at Austin, 105 E. 24th Street, Stop A5300, Austin, Texas 78712, United States
| | - C. Buddie Mullins
- McKetta Department of Chemical Engineering and Department of Chemistry, Texas Materials Institute, Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712-0231, United States
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9
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Han S, Mullins CB. Surface Alloy Composition Controlled O2 Activation on Pd–Au Bimetallic Model Catalysts. ACS Catal 2018. [DOI: 10.1021/acscatal.8b00140] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Kunwar S, Pandey P, Sui M, Bastola S, Lee J. Morphological and optical properties of Pd xAg 1-x alloy nanoparticles. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2018; 19:160-173. [PMID: 29511394 PMCID: PMC5827785 DOI: 10.1080/14686996.2018.1435944] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 01/30/2018] [Accepted: 01/30/2018] [Indexed: 05/29/2023]
Abstract
Alloy nanoparticles (NPs) can offer a wide range of opportunities for various applications due to their composition and structure dependent properties such as multifunctionality, electronic heterogeneity, site-specific response, and multiple plasmon resonance bands. In this work, the fabrication of self-assembled PdxAg1-x NPs alloy nanostructures with distinct size, density, shape, and composition is demonstrated via the solid-state dewetting of sputtered Pd/Ag thin films on c-plane sapphire. The initial stage of bilayer dewetting exhibits the nucleation of voids, followed by the expansion of voids and cluster breakdown and finally shape transformation along with the temperature control. Bilayer composition shows a substantial influence on the dewetting such that the overall dewetting is enhanced along with the increased Ag composition, i.e. Pd0.25Ag0.75 > Pd0.5Ag0.5 > Pd0.75Ag0.25. On the other hand, the size and density of NPs can be efficiently controlled by varying the initial thickness of bilayers. Reflectance peaks in UV and near-infrared (NIR) regions and a wide absorption band in the visible region arisen from the surface plasmon resonance are observed in reflectance spectra. The peak intensity depends on the composition of PdxAg1-x NPs and the NIR peaks gradually blue-shift with the size decrement.
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Affiliation(s)
- Sundar Kunwar
- College of Electronics and Information, Kwangwoon University, Seoul, South Korea
| | - Puran Pandey
- College of Electronics and Information, Kwangwoon University, Seoul, South Korea
| | - Mao Sui
- College of Electronics and Information, Kwangwoon University, Seoul, South Korea
| | - Sushil Bastola
- College of Electronics and Information, Kwangwoon University, Seoul, South Korea
| | - Jihoon Lee
- College of Electronics and Information, Kwangwoon University, Seoul, South Korea
- Institute of Nanoscale Science and Engineering, University of Arkansas, Fayetteville, AR, USA
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11
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State R, Papa F, Tabakova T, Atkinson I, Negrila C, Balint I. Photocatalytic abatement of trichlorethylene over Au and Pd–Au supported on TiO2 by combined photomineralization/hydrodechlorination reactions under simulated solar irradiation. J Catal 2017. [DOI: 10.1016/j.jcat.2016.11.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Han S, Evans EJ, Mullen GM, Mullins CB. H2O-Improved O2 activation on the Pd–Au bimetallic surface. Chem Commun (Camb) 2017; 53:3990-3993. [DOI: 10.1039/c7cc01542a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Co-adsorbed H2O enhances the activation of adsorbed O2 on the Pd–Au(111) surface.
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Affiliation(s)
- Sungmin Han
- Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry
- University of Texas at Austin
| | - Edward J. Evans
- Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry
- University of Texas at Austin
| | - Gregory M. Mullen
- McKetta Department of Chemical Engineering
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry
- University of Texas at Austin
| | - C. Buddie Mullins
- Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry
- University of Texas at Austin
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13
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Evans EJ, Li H, Yu WY, Mullen GM, Henkelman G, Mullins CB. Mechanistic insights on ethanol dehydrogenation on Pd–Au model catalysts: a combined experimental and DFT study. Phys Chem Chem Phys 2017; 19:30578-30589. [DOI: 10.1039/c7cp05097f] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
UHV experiments and DFT show the dependence of the ethanol dehydrogenation mechanism on the Pd ensemble size on Au(111).
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Affiliation(s)
- E. J. Evans
- McKetta Department of Chemical Engineering and Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry, and Institute for Computational Engineering and Sciences
- University of Texas at Austin
| | - H. Li
- Department of Chemistry, Institute for Computational and Engineering Sciences
- Texas Materials Institute
- The University of Texas at Austin
- Austin
- USA
| | - Wen-Yueh Yu
- McKetta Department of Chemical Engineering and Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry, and Institute for Computational Engineering and Sciences
- University of Texas at Austin
| | - G. M. Mullen
- McKetta Department of Chemical Engineering and Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry, and Institute for Computational Engineering and Sciences
- University of Texas at Austin
| | - G. Henkelman
- Department of Chemistry, Institute for Computational and Engineering Sciences
- Texas Materials Institute
- The University of Texas at Austin
- Austin
- USA
| | - C. Buddie Mullins
- McKetta Department of Chemical Engineering and Department of Chemistry
- Center for Nano and Molecular Science and Technology
- Texas Materials Institute
- Center for Electrochemistry, and Institute for Computational Engineering and Sciences
- University of Texas at Austin
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14
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Fang YL, Heck KN, Zhao Z, Pretzer LA, Guo N, Wu T, Miller JT, Wong MS. Gold-doping of carbon-supported palladium improves reduction catalysis. CHINESE JOURNAL OF CATALYSIS 2016. [DOI: 10.1016/s1872-2067(16)62530-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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15
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Rietzler F, May B, Steinrück HP, Maier F. Switching adsorption and growth behavior of ultrathin [C 2C 1Im][OTf] films on Au(111) by Pd deposition. Phys Chem Chem Phys 2016; 18:25143-25150. [PMID: 27711556 DOI: 10.1039/c6cp04938a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Combining in vacuo deposition of ultrathin ionic liquid (UTIL) films with angle-resolved X-ray photoelectron spectroscopy (ARXPS), we demonstrate that by deposition of submonolayer amounts of Pd onto Au(111) the initial growth mode of the ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([C2C1Im][OTf]) can be switched from three-dimensional (3D) to two-dimensional (2D) growth, that is, from non-wetting to wetting. On clean Au(111), pronounced 3D growth occurs on top of an initially formed 2D wetting layer with cations and anions next to each other in a checkerboard arrangement. After pre- or postdeposition of only 0.7 ML Pd, two-dimensional layer-by-layer growth is found, which is attributed to strong attractive interactions between [C2C1Im][OTf] and surface Pd. For Pd post deposition onto the IL, the ARXPS data revealed particularly strong interactions between the dialkylimidazolium cation and Pd atoms, which considerably reduce the regular surface alloying of Pd with the Au substrate stabilizing Pd at the metal surface. In the context of heterogeneous catalysis using the SCILL (solid catalyst coated with ionic liquid layer) concept, these results directly provide a possible explanation on the molecular level for the beneficial influence of the IL layer in case of heterogeneous metal alloy catalysts.
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Affiliation(s)
- F Rietzler
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
| | - B May
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
| | - H-P Steinrück
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
| | - F Maier
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany.
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16
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Dimitrov N. Recent Advances in the Growth of Metals, Alloys, and Multilayers by Surface Limited Redox Replacement (SLRR) Based Approaches. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.05.115] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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17
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Languille M, Ehret E, Lee H, Jeong C, Toyoshima R, Kondoh H, Mase K, Jugnet Y, Bertolini J, Aires FCS, Mun B. In-situ surface analysis of AuPd(1 1 0) under elevated pressure of CO. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.05.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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18
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Soldo-Olivier Y, De Santis M, Liang W, Sibert E. Growth mechanisms of Pd nanofilms electrodeposited onto Au(111): an in situ grazing incidence X-ray diffraction study. Phys Chem Chem Phys 2016; 18:2830-9. [PMID: 26728225 DOI: 10.1039/c5cp05985b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electrochemical deposition of ultra-thin Pd films onto Au(111) single crystals in a solution containing chloride was studied with in situ surface X-ray diffraction measurements. We report a detailed description of the growth mode, as well as film morphology and lattice parameters as a function of thickness, from 2 up to 10 monolayers (ML) as equivalent thickness. An almost ideal layer-by-layer pseudomorphic growth is observed up to two deposited ML. For higher thicknesses, it is followed by the growth of large 3D Pd bulk-like islands. They are about 20 ± 5 ML high and ∼220 Å in diameter for the Pd4ML film and occupy only about 20% of the surface. Their height increases faster than their size with the Pd deposited amount. We could clearly show that chlorides do not play any role in inhibiting the three-dimensional growth of Pd/Au(111) films. We could also unequivocally correlate the features observed by electrochemical surface characterisation in an acidic medium with the detailed structure obtained by diffraction.
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Affiliation(s)
- Yvonne Soldo-Olivier
- University Grenoble Alpes, LEPMI, F-38000 Grenoble, France. and CNRS, LEPMI, F-38000 Grenoble, France
| | | | - Wang Liang
- University Grenoble Alpes, LEPMI, F-38000 Grenoble, France. and CNRS, LEPMI, F-38000 Grenoble, France
| | - Eric Sibert
- University Grenoble Alpes, LEPMI, F-38000 Grenoble, France. and CNRS, LEPMI, F-38000 Grenoble, France
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19
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Mehl S, Toghan A, Bauer T, Brummel O, Taccardi N, Wasserscheid P, Libuda J. Pd Nanoparticle Formation in Ionic Liquid Thin Films Monitored by in situ Vibrational Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12126-12139. [PMID: 26479118 DOI: 10.1021/acs.langmuir.5b03386] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ionic liquids (ILs) are flexible reaction media and solvents for the synthesis of metal nanoparticles (NPs). Here, we describe a new preparation method for metallic NPs in nanometer thick films of ultraclean ILs in an ultrahigh vacuum (UHV) environment. CO-covered Pd NPs are formed by simultaneous and by sequential physical vapor deposition (PVD) of the IL and the metal in the presence of low partial pressures of CO. The film thickness and the particle size can be controlled by the deposition parameters. We followed the formation of the NPs and their thermal behavior by time-resolved IR reflection absorption spectroscopy (TP-IRAS) and by temperature-programmed IRAS (TR-IRAS). Codeposition of Pd and [C1C2Im][OTf] in CO at 100 K leads to the growth of homogeneous multilayer films of CO-covered Pd aggregates in an IL matrix. The size of these NPs can be controlled by the metal fraction in the co-deposit. With increasing metal fraction, the size of the Pd NPs also increases. At very low metal content, small Pd carbonyl-like species are formed, which bind CO in on-top geometry only. Upon annealing, the [OTf](-) anion coadsorbs at the NP surface and partially displaces CO. Co-adsorption of CO and IL is indicated by a strong red-shift of the CO stretching bands. While the weakly bound on-top CO is mainly replaced below the melting transition of the IL, coadsorbate shells with bridge-bonded CO and IL are stable well above the melting point. Larger three-dimensional Pd NPs can be prepared by PVD of Pd onto a solid [C1C2Im][OTf] film at 100 K. Upon annealing, on-top CO desorbs from these NPs below 200 K. Upon melting of the IL film, the CO-covered Pd NPs immerse into the IL and again form a stable coadsorbate shell that consists of bridge-bonded CO and the IL.
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Affiliation(s)
| | - Arafat Toghan
- Chemistry Department, Faculty of Science, South Valley University , 83523 Qena, Egypt
| | | | | | | | - Peter Wasserscheid
- Erlangen Catalysis Resource Center and Interdisciplinary Center Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91058 Erlangen, Germany
| | - Jörg Libuda
- Erlangen Catalysis Resource Center and Interdisciplinary Center Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91058 Erlangen, Germany
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20
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Ma JX, Yang H, Li S, Ren R, Li J, Zhang X, Ma J. Well-dispersed graphene-polydopamine-Pd hybrid with enhanced catalytic performance. RSC Adv 2015. [DOI: 10.1039/c5ra13361k] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A graphene-polydopamine hybrid was prepared and decorated with ultrafine Pd nanoparticles to give a stable catalyst that disperses well in polar solvents. Its catalytic activity was investigated in the reduction of 4-nitrophenol, K3[Fe(CN)6], methylene blue and rhodamine B.
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Affiliation(s)
- Jian-Xin Ma
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Honglei Yang
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Shuwen Li
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Ren Ren
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Jing Li
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Xueyao Zhang
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
| | - Jiantai Ma
- State Key Laboratory of Applied Organic Chemistry
- Gansu Provincial Engineering Laboratory for Chemical Catalysis
- College of Chemistry and Chemical Engineering
- Lanzhou University
- Lanzhou 730000
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21
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Yu WY, Zhang L, Mullen GM, Evans EJ, Henkelman G, Mullins CB. Effect of annealing in oxygen on alloy structures of Pd–Au bimetallic model catalysts. Phys Chem Chem Phys 2015. [DOI: 10.1039/c5cp03515e] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Annealing in an oxygen ambient stabilizes Pd atoms on Pd–Au surfaces, resulting in higher oxygen uptake and CO oxidation activity.
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Affiliation(s)
- Wen-Yueh Yu
- McKetta Department of Chemical Engineering
- University of Texas at Austin
- Austin
- USA
| | - Liang Zhang
- Department of Chemistry
- University of Texas at Austin
- Austin
- USA
- Institute for Computational Engineering and Sciences
| | - Gregory M. Mullen
- McKetta Department of Chemical Engineering
- University of Texas at Austin
- Austin
- USA
| | - Edward J. Evans
- Department of Chemistry
- University of Texas at Austin
- Austin
- USA
| | - Graeme Henkelman
- Department of Chemistry
- University of Texas at Austin
- Austin
- USA
- Institute for Computational Engineering and Sciences
| | - C. Buddie Mullins
- McKetta Department of Chemical Engineering
- University of Texas at Austin
- Austin
- USA
- Department of Chemistry
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22
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Saqlain MA, Hussain A, Siddiq M, Leitão AA. Synergy between Pd and Au in a Pd–Au(100) bimetallic surface for the water gas shift reaction: a DFT study. RSC Adv 2015. [DOI: 10.1039/c5ra07163a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Density functional theory calculations were performed to model a reaction relevant bimetallic surface and study the water gas shift reaction.
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Affiliation(s)
| | - Akhtar Hussain
- TPD
- Pakistan Institute of Nuclear Science and Technology
- PINSTECH
- Islamabad
- Pakistan
| | - Muhammad Siddiq
- Department of Chemistry
- Quaid-i-Azam University
- Islamabad
- Pakistan
| | - Alexandre A. Leitão
- Departamento de Química
- Universidade Federal de Juiz de Fora
- Juiz de Fora
- Brazil
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23
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Yu WY, Mullen GM, Flaherty DW, Mullins CB. Selective Hydrogen Production from Formic Acid Decomposition on Pd–Au Bimetallic Surfaces. J Am Chem Soc 2014; 136:11070-8. [DOI: 10.1021/ja505192v] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Wen-Yueh Yu
- McKetta
Department of Chemical Engineering and Department of Chemistry, Center
for Nano and Molecular Science and Technology, Texas Materials Institute,
and Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Gregory M. Mullen
- McKetta
Department of Chemical Engineering and Department of Chemistry, Center
for Nano and Molecular Science and Technology, Texas Materials Institute,
and Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - David W. Flaherty
- Department of Chemical & Biomolecular Engineering, University of Illinois at Urbana—Champaign, Urbana, Illinois 61801, United States
| | - C. Buddie Mullins
- McKetta
Department of Chemical Engineering and Department of Chemistry, Center
for Nano and Molecular Science and Technology, Texas Materials Institute,
and Center for Electrochemistry, University of Texas at Austin, Austin, Texas 78712, United States
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24
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Qian H, Zhao Z, Velazquez JC, Pretzer LA, Heck KN, Wong MS. Supporting palladium metal on gold nanoparticles improves its catalysis for nitrite reduction. NANOSCALE 2014; 6:358-364. [PMID: 24195966 DOI: 10.1039/c3nr04540d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Nitrate (NO3(-)) and nitrite (NO2(-)) anions are often found in groundwater and surface water as contaminants globally, especially in agricultural areas due to nitrate-rich fertilizer use. One popular approach to studying the removal of nitrite/nitrate from water has been their degradation to dinitrogen via Pd-based reduction catalysis. However, little progress has been made towards understanding how the catalyst structure can improve activity. Focusing on the catalytic reduction of nitrite in this study, we report that Au NPs supporting Pd metal ("Pd-on-Au NPs") show catalytic activity that varies with volcano-shape dependence on Pd surface coverage. At room temperature, in CO2-buffered water, and under H2 headspace, the NPs were maximally active at a Pd surface coverage of 80%, with a first-order rate constant (k(cat) = 576 L g(Pd)(-1) min(-1)) that was 15x and 7.5x higher than monometallic Pd NPs (~4 nm; 40 L g(Pd)(-1) min(-1)) and Pd/Al2O3 (1 wt% Pd; 76 L g(Pd)(-1) min(-1)), respectively. Accounting only for surface Pd atoms, these NPs (576 L g(surface-Pd)(-1) min(-1)) were 3.6x and 1.6x higher than monometallic Pd NPs (160 L g(surface-Pd)(-1) min(-1)) and Pd/Al2O3 (361 L g(surface-Pd)(-1) min(-1)). These NPs retained ~98% of catalytic activity at a chloride concentration of 1 mM, whereas Pd/Al2O3 lost ~50%. The Pd-on-Au nanostructure is a promising approach to improve the catalytic reduction process for nitrite and, with further development, also for nitrate anions.
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Affiliation(s)
- Huifeng Qian
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, TX 77005-1892, USA.
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25
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Arrigo R, Schuster ME, Abate S, Wrabetz S, Amakawa K, Teschner D, Freni M, Centi G, Perathoner S, Hävecker M, Schlögl R. Dynamics of palladium on nanocarbon in the direct synthesis of H2O2. CHEMSUSCHEM 2014; 7:179-194. [PMID: 24133011 DOI: 10.1002/cssc.201300616] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Indexed: 06/02/2023]
Abstract
This work aims to clarify the nanostructural transformation accompanying the loss of activity and selectivity for the hydrogen peroxide synthesis of palladium and gold-palladium nanoparticles supported on N-functionalized carbon nanotubes. High-resolution X-ray photoemission spectroscopy (XPS) allows the discrimination of metallic palladium, electronically modified metallic palladium hosting impurities, and cationic palladium. This is paralleled by the morphological heterogeneity observed by high-resolution TEM, in which nanoparticles with an average size of 2 nm coexisted with very small palladium clusters. The morphological distribution of palladium is modified after reaction through sintering and dissolution/redeposition pathways. The loss of selectivity is correlated to the extent to which these processes occur as a result of the instability of the particle at the carbon surface. We assign beneficial activity in the selective hydrogenation of oxygen to palladium clusters with a modified electronic structure compared with palladium metal or palladium oxides. These beneficial species are formed and stabilized on carbons modified with nitrogen atoms in substitutional positions. The formation of larger metallic palladium particles not only reduces the number of active sites for the synthesis, but also enhances the activity for deep hydrogenation to water. The structural instability of the active species is thus detrimental in a dual way. Minimizing the chance of sintering of palladium clusters by all means is thus the key to better performing catalysts.
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Affiliation(s)
- Rosa Arrigo
- Dept. Anorganische Chemie, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr (Germany).
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26
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Pei GX, Liu XY, Wang A, Li L, Huang Y, Zhang T, Lee JW, Jang BWL, Mou CY. Promotional effect of Pd single atoms on Au nanoparticles supported on silica for the selective hydrogenation of acetylene in excess ethylene. NEW J CHEM 2014. [DOI: 10.1039/c3nj01136d] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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27
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Hu S, Scudiero L, Ha S. Electronic effect of Pd-transition metal bimetallic surfaces toward formic acid electrochemical oxidation. Electrochem commun 2014. [DOI: 10.1016/j.elecom.2013.11.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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28
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Chen LY, Chen N, Hou Y, Wang ZC, Lv SH, Fujita T, Jiang JH, Hirata A, Chen MW. Geometrically Controlled Nanoporous PdAu Bimetallic Catalysts with Tunable Pd/Au Ratio for Direct Ethanol Fuel Cells. ACS Catal 2013. [DOI: 10.1021/cs400135k] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- L. Y. Chen
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - N. Chen
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Y. Hou
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Z. C. Wang
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - S. H. Lv
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - T. Fujita
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - J. H. Jiang
- State Key Laboratory of Metal Matrix Composites
and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - A. Hirata
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - M. W. Chen
- WPI-Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
- State Key Laboratory of Metal Matrix Composites
and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
- CREST,
Japan Science and Technology Agency, Saitama 332-0012, Japan
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29
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Mitchell C, Fayette M, Dimitrov N. Homo- and hetero-epitaxial deposition of Au by surface limited redox replacement of Pb underpotentially deposited layer in one-cell configuration. Electrochim Acta 2012. [DOI: 10.1016/j.electacta.2012.08.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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30
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Affiliation(s)
- Jinlong Gong
- Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
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31
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Pancotti A, Nascente PAP, de Siervo A, Landers R, Carazzolle MF, Tallarico DA, Kleiman GG. Characterization of Ultra-Thin Films of Pd Deposited on Au(111). Top Catal 2011. [DOI: 10.1007/s11244-011-9649-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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32
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Boscoboinik J, Kestell J, Garvey M, Weinert M, Tysoe WT. Creation of Low-Coordination Gold Sites on Au(111) Surface by 1,4-phenylene Diisocyanide Adsorption. Top Catal 2011. [DOI: 10.1007/s11244-011-9642-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Fang YL, Heck KN, Alvarez PJJ, Wong MS. Kinetics Analysis of Palladium/Gold Nanoparticles as Colloidal Hydrodechlorination Catalysts. ACS Catal 2011. [DOI: 10.1021/cs100067k] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yu-Lun Fang
- Department of Chemical and Biomolecular Engineering,
| | | | - Pedro J. J. Alvarez
- Department of Civil and Environmental Engineering,
- Center for Biological and Environmental Nanotechnology, and
| | - Michael S. Wong
- Department of Chemical and Biomolecular Engineering,
- Center for Biological and Environmental Nanotechnology, and
- Department of Chemistry, Rice University, 6100 South Main Street, Houston, Texas 77005, United States
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34
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Fratesi G. First-principles investigation of the early stages of Pd adsorption on Au(111). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:015001. [PMID: 21406816 DOI: 10.1088/0953-8984/23/1/015001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We present the results of density functional theory simulations of the adsorption of Pd on the Au(111) surface at low coverage. The potential energy surface for Pd adatoms is determined and found to be shallower than that related to atomic-size features observed in scanning tunneling experiments. The commonly found Pd-Pd repulsion within Au also applies in the case of adatoms on a perfect Au(111) surface interacting with surface/subsurface ones, despite the role of the latter entities in the island nucleation on the real, reconstructed surface. Alteration of the surface lattice parameter or of the stacking of Au layers, featured by the Au(111)-[Formula: see text] surface, is also modeled and found not to modify the energetics of Pd islands. The appearance of Pd monomers in simulated scanning tunneling topographies is discussed and shows an important contribution by the Au surface state in determining the relative height of surface and subsurface Pd atoms, in agreement with recent experimental findings.
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Affiliation(s)
- Guido Fratesi
- ETSF and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 53, 20125 Milano, Italy.
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35
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Andersin J, Honkala K. First principles investigations of Pd-on-Au nanostructures for trichloroethene catalytic removal from groundwater. Phys Chem Chem Phys 2011; 13:1386-94. [DOI: 10.1039/c0cp00524j] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Wang T, Li B, Yang J, Chen H, Chen L. First principles study of oxygen adsorption and dissociation on the Pd/Au surface alloys. Phys Chem Chem Phys 2011; 13:7112-20. [DOI: 10.1039/c0cp02007a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Takahasi M, Tamura K, Mizuki J, Kondo T, Uosaki K. Orientation dependence of Pd growth on Au electrode surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:474002. [PMID: 21386609 DOI: 10.1088/0953-8984/22/47/474002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The structure of thin Pd films grown on Au(111) and Au(001) electrodes in a solution containing PdCl(4)(2 -) and SO(4)(2 -) has been investigated by surface x-ray scattering. This technique provided structural information on the Pd films in the lateral direction as well as in the surface normal direction. Comparison of Pd/Au(111) and Pd/Au(001) growth modes shows similarity in the first layer deposition. On Au(111) and Au(001) substrates, Pd follows the crystal structure of the substrates and forms a pseudomorphic monolayer. Beyond 2 ML, however, Pd films grown on Au(111) are relaxed, although there are still pseudomorphic layers at the interface. In contrast, Pd films on Au(001) continue to grow pseudomorphically over 10 ML. The difference in the growth mode between (111) and (001) surfaces is not ascribable only to anisotropy in the elasticity of the film. The relationship between a growing surface and an allowed gliding plane in misfit dislocations is presented as a crucial factor determining the critical thickness of the film.
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Affiliation(s)
- M Takahasi
- Synchrotron Radiation Research Center, Japan Atomic Energy Agency, Sayo-cho, Hyogo 679-5148, Japan
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38
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Baber AE, Tierney HL, Lawton TJ, Sykes ECH. An Atomic-Scale View of Palladium Alloys and their Ability to Dissociate Molecular Hydrogen. ChemCatChem 2010. [DOI: 10.1002/cctc.201000309] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Sarapuu A, Kasikov A, Wong N, Lucas CA, Sedghi G, Nichols RJ, Tammeveski K. Electroreduction of oxygen on gold-supported nanostructured palladium films in acid solutions. Electrochim Acta 2010. [DOI: 10.1016/j.electacta.2010.05.092] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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40
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Baber AE, Tierney HL, Sykes ECH. Atomic-scale geometry and electronic structure of catalytically important pd/au alloys. ACS NANO 2010; 4:1637-1645. [PMID: 20146438 DOI: 10.1021/nn901390y] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Pd/Au bimetallic alloys catalyze many important reactions ranging from the synthesis of vinyl acetate and hydrogen peroxide to the oxidation of carbon monoxide and trimerization of acetylene. It is known that the atomic-scale geometry of these alloys can dramatically affect both their reactivity and selectivity. However, there is a distinct lack of experimental characterization and quantification of ligand and ensemble effects in this system. Low-temperature, ultrahigh vacuum scanning tunneling microscopy is used to investigate the atomic-scale geometry of Pd/Au111 near-surface alloys and to spectroscopically probe their local electronic structure. The results reveal that the herringbone reconstruction of Au111 provides entry sites for the incorporation of Pd atoms in the Au surface and that the degree of mixing is dictated by the surface temperature. At catalytically relevant temperatures the distribution of low coverages of Pd in the alloy is random, except for a lack of nearest neighbor pairs in both the surface and subsurface sites. Scanning tunneling spectroscopy is used to examine the electronic structure of the individual Pd atoms in surface and subsurface sites. This work reveals that in both surface and subsurface locations, Pd atoms display a very similar electronic structure to the surrounding Au atoms. However, individual surface and subsurface Pd atoms are depleted of charge in a very narrow region at the band edge of the Au surface state. dI/dV images of the phenomena demonstrate the spatial extent of this electronic perturbation.
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Affiliation(s)
- Ashleigh E Baber
- Department of Chemistry, Tufts University, Medford, Massachusetts 02155-5813
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41
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Villa A, Wang D, Su D, Veith GM, Prati L. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts. Phys Chem Chem Phys 2010; 12:2183-9. [DOI: 10.1039/b919322g] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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42
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43
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Damian A, Maroun F, Allongue P. Selective growth and dissolution of Ni on a PdAu bimetallic surface by in situ STM: determining the relative adsorbate-substrate interaction energy. PHYSICAL REVIEW LETTERS 2009; 102:196101. [PMID: 19518976 DOI: 10.1103/physrevlett.102.196101] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Indexed: 05/27/2023]
Abstract
By studying the electrochemical growth and dissolution of a Ni monolayer on a PdAu bimetallic surface with in situ STM, we demonstrate that Ni grows preferentially on Au(111) in a wide potential range. In contrast, a Ni monolayer covering the entire bimetallic surface can be selectively dissolved from Pd islands. We show that the Ni-substrate interactions play a key role in this selectivity, and we estimate the binding energy of Ni to Pd to be 80 meV smaller than that of Ni to Au.
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Affiliation(s)
- A Damian
- Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128 Palaiseau, France
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44
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CHEN M, GOODMAN D. Promotional Effects of Au in Pd-Au Catalysts for Vinyl Acetate Synthesis. CHINESE JOURNAL OF CATALYSIS 2008. [DOI: 10.1016/s1872-2067(09)60021-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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45
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46
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Ferri D, Behzadi B, Kappenberger P, Hauert R, Ernst KH, Baiker A. Probing the interface in vapor-deposited bimetallic Pd-Au and Pt-Au films by CO adsorption from the liquid phase. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:1203-8. [PMID: 17241033 DOI: 10.1021/la0623477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Bimetallic Pd-Au and Pt-Au and monometallic Pd, Pt, and Au films were prepared by physical vapor deposition. The resulting surfaces were characterized by means of XPS, AFM, and CO adsorption from the liquid phase (CH2Cl2) monitored by ATR-IR spectroscopy. CO adsorption combined with ATR-IR proved to be a very sensitive method for probing the degree of interdiffusion occurring at the interfaces whose properties were altered by variation of the Pd and Pt film thickness from 0.2 to 2 nm. Because no CO adsorption was observed on Au, the evaporation of Pt-group metals on Au allowed us to study the effect of dilution on the adsorption properties of the surfaces. At equivalent Pd film thickness, the evaporation of Au reduced the amount of adsorbed CO and caused the formation of 2-fold bridging CO, which was almost absent in monometallic surfaces. Additionally, the average particle size on Pd-Au surfaces was smaller than that on monometallic Pd surfaces. The results indicate that a Pd/Au diffuse interface is formed that affects the Pd particle size even more drastically than the simple decrease in Pd film thickness in monometallic surfaces. Pt-Au surfaces were less sensitive to CO adsorption, indicating that the two metals do not mix to a significant extent. The difference in the interfacial behavior of Pd and Pt in the bimetallic gold films is traced to the largely different Pd-Au and Pt-Au miscibility gaps.
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Affiliation(s)
- Davide Ferri
- Department of Chemistry and Applied Biosciences, ETH Zurich, HCI, CH-8093 Zurich, Switzerland
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47
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Behzadi B, Vargas A, Ferri D, Ernst KH, Baiker A. Cinchonidine Adsorption on Gold and Gold-Containing Bimetallic Platinum Metal Surfaces: An Attenuated Total Reflection Infrared and Density Functional Theory Study. J Phys Chem B 2006; 110:17082-9. [PMID: 16928003 DOI: 10.1021/jp062174u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Adsorption of cinchonidine on monometallic Au and bimetallic Pt-Au and Pd-Au thin model films prepared by physical vapor deposition has been investigated with attenuated total reflection infrared (ATR-IR) spectroscopy. On Au the alkaloid forms an adsorbed layer that shows higher stability against desorption than the corresponding adsorption on Pt. In this adsorption layer the intermolecular interactions dominate over metal-adsorbate interactions as indicated by the absence of the spectroscopic features attributed to strongly flat adsorbed species. This behavior is further supported by Density Functional Theory (DFT) calculations indicating that flat and tilted orientations of the quinoline ring have comparable adsorption energy on Au but lower (7-10 kcal/mol) compared to adsorption on Pt (ca. 40 kcal/mol). As a consequence, the creation of a metal surface with isolated chiral sites is prevented by formation of an adsorbed structure formed by intermolecularly bound cinchonidine molecules on Au. While the binding to Pt is due to the formation of sigma-bonds to surface atoms, such aggregates are bound to Au mainly by van der Waals forces. Given this different nature of bonding of cinchonidine to Au and Pt, addition of Au to Pt and Pd films could be used to probe the changes of fractional coverage of the different adsorbed species of cinchonidine on the platinum metals. It is demonstrated that the lowering of the domain size of the platinum group metal by Au can simulate the effect of particle size on the distribution of the surface conformations of the alkaloid on a metal surface.
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Affiliation(s)
- Bahar Behzadi
- Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, HCI, CH-8093 Zurich, Switzerland
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48
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Luo K, Wei T, Yi CW, Axnanda S, Goodman DW. Preparation and Characterization of Silica Supported Au−Pd Model Catalysts. J Phys Chem B 2005; 109:23517-22. [PMID: 16375326 DOI: 10.1021/jp0553131] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Au-Pd bimetallic model catalysts were synthesized as alloy clusters on SiO2 ultrathin films under ultrahigh vacuum (UHV) conditions. The surface composition and morphology were characterized with low energy ion scattering spectroscopy (LEIS), infrared reflection absorption spectroscopy (IRAS), and temperature programmed desorption (TPD). Relative to the bulk, the surface of the clusters is enriched in Au. With CO as a probe, IRAS and TPD were used to identify isolated Pd sites at the surface of the supported Au-Pd clusters. Ethylene adsorption and dehydrogenation show a clear structure-reactivity correlation with respect to the structure/composition of these Au-Pd model catalysts.
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Affiliation(s)
- K Luo
- Department of Chemistry, Texas A&M University, P. O. Box 30012, College Station, Texas 77842-3012, USA
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49
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Chen M, Kumar D, Yi CW, Goodman DW. The Promotional Effect of Gold in Catalysis by Palladium-Gold. Science 2005; 310:291-3. [PMID: 16224016 DOI: 10.1126/science.1115800] [Citation(s) in RCA: 562] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Acetoxylation of ethylene to vinyl acetate (VA) was used to investigate the mechanism of the promotional effect of gold (Au) in a palladium (Pd)-Au alloy catalyst. The enhanced rates of VA formation for low Pd coverages relative to high Pd coverages on Au single-crystal surfaces demonstrate that the critical reaction site for VA synthesis consists of two noncontiguous, suitably spaced, Pd monomers. The role of Au is to isolate single Pd sites that facilitate the coupling of critical surface species to product, while inhibiting the formation of undesirable reaction by-products.
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Affiliation(s)
- Mingshu Chen
- Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA
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50
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Yi CW, Luo K, Wei T, Goodman DW. The Composition and Structure of Pd−Au Surfaces. J Phys Chem B 2005; 109:18535-40. [PMID: 16853387 DOI: 10.1021/jp053515r] [Citation(s) in RCA: 251] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pd, Au, and Pd-Au mixtures were deposited via physical vapor deposition onto a Mo(110) substrate, and the surface concentration and morphology of the Pd-Au mixtures were determined by low-energy ion scattering spectroscopy (LEISS), infrared absorption spectroscopy (IRAS), temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS). Pd-Au mixtures form a stable alloy between 700 and 1000 K with substantial enrichment in Au compared to the bulk composition. Annealing a 1:1 Pd-Au mixture at 800 K leads to the formation of a surface alloy with a composition Au(0.8)Pd(0.2) where Pd is predominantly surrounded by Au. The surface concentration of this isolated Pd site can be systematically controlled by altering the bulk Pd-Au alloy concentration.
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Affiliation(s)
- C-W Yi
- Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842-3012, USA
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