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Effect of the reductive treatment on the state and electrocatalytic behavior of Pt in catalysts supported on Ti0.8Mo0.2O2-C composite. REACTION KINETICS MECHANISMS AND CATALYSIS 2021. [DOI: 10.1007/s11144-021-02131-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractTi(1-x)MoxO2-carbon composites are promising new supports for Pt-based electrocatalysts in polymer electrolyte membrane fuel cells offering exciting catalytic properties and enhanced stability against electrocorrosion. Pt and the mixed oxide form a couple liable for strong metal-support interaction (SMSI) phenomenon, generally manifesting itself in decoration of the metal particles by ultrathin layers of the support material upon annealing under reductive conditions. The aim of this work is to evaluate the SMSI phenomenon as a potential strategy for tailoring the properties of the electrocatalyst. A 20 wt% Pt/50 wt% Ti0.8Mo0.2O2-50 wt% C electrocatalyst prepared on Black Pearls 2000 carbon functionalized with HNO3 and glucose was reduced at 250 °C in H2 in order to induce SMSI. The electrocatalytic properties and the stability of the reduced and the original catalysts were analyzed by cyclic voltammetry and COads stripping voltammetry. Structural investigations as well as X-ray photoelectron spectroscopy (XPS) measurements were performed in order to obtain information about the details of the interaction between the oxide and the Pt particles. The electrochemical experiments pointed out a small loss of the electrochemically active surface area of Pt in the reduced catalyst along with enhanced stability with respect to the original one, while structural studies suggested only a minimal decrease of the Pt dispersion. At the same time, hydrogen exposure experiments combined with XPS demonstrated the presence of Mo species directly adsorbed on the Pt surface. Thus, the properties of the reduced catalyst can be traced to decoration of the surface of Pt by Mo-containing species.
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2
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Palotás K, Óvári L, Vári G, Gubó R, Farkas AP, Kiss J, Berkó A, Kónya Z. Au–Rh Surface Structures on Rh(111): DFT Insights into the Formation of an Ordered Surface Alloy. THE JOURNAL OF PHYSICAL CHEMISTRY C 2018. [DOI: 10.1021/acs.jpcc.8b05744] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Krisztián Palotás
- Department of Complex Physical Systems, Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9., SK-84511 Bratislava, Slovakia
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
- Department of Theoretical Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
| | - László Óvári
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
- ELI-ALPS, ELI-HU Nonprofit Ltd., Dugonics tér 13., H-6720 Szeged, Hungary
| | - Gábor Vári
- Department of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
| | - Richárd Gubó
- ELI-ALPS, ELI-HU Nonprofit Ltd., Dugonics tér 13., H-6720 Szeged, Hungary
- Department of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
| | - Arnold P. Farkas
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
- ELI-ALPS, ELI-HU Nonprofit Ltd., Dugonics tér 13., H-6720 Szeged, Hungary
| | - János Kiss
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
| | - András Berkó
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
| | - Zoltán Kónya
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
- Department of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., H-6720 Szeged, Hungary
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Gubó R, Vári G, Kiss J, Farkas AP, Palotás K, Óvári L, Berkó A, Kónya Z. Tailoring the hexagonal boron nitride nanomesh on Rh(111) with gold. Phys Chem Chem Phys 2018; 20:15473-15485. [PMID: 29799587 DOI: 10.1039/c8cp00790j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The pore diameter (depth) of the periodically corrugated h-BN monolayer (“nanomesh”) can be tuned allyoing Au into the Rh(111) surface.
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Affiliation(s)
- R. Gubó
- Extreme Light Infrastructure-ALPS
- ELI-HU Non-profit Ltd
- H-6720 Szeged
- Hungary
- Department of Applied and Environmental Chemistry, University of Szeged
| | - G. Vári
- Department of Applied and Environmental Chemistry, University of Szeged
- H-6720 Szeged
- Hungary
| | - J. Kiss
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
| | - A. P. Farkas
- Extreme Light Infrastructure-ALPS
- ELI-HU Non-profit Ltd
- H-6720 Szeged
- Hungary
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
| | - K. Palotás
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
- Institute of Physics
- Slovak Academy of Sciences
| | - L. Óvári
- Extreme Light Infrastructure-ALPS
- ELI-HU Non-profit Ltd
- H-6720 Szeged
- Hungary
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
| | - A. Berkó
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
| | - Z. Kónya
- Department of Applied and Environmental Chemistry, University of Szeged
- H-6720 Szeged
- Hungary
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
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Gubó R, Yim CM, Allan M, Pang CL, Berkó A, Thornton G. Variation of SMSI with the Au:Pd Ratio of Bimetallic Nanoparticles on TiO 2(110). Top Catal 2017; 61:308-317. [PMID: 31258302 PMCID: PMC6560464 DOI: 10.1007/s11244-017-0854-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Au/Pd nanoparticles are important in a number of catalytic processes. Here we investigate the formation of Au-Pd bimetallic nanoparticles on TiO2(110) and their susceptibility to encapsulation using scanning tunneling microscopy, as well as Auger spectroscopy and low energy electron diffraction. Sequentially depositing 5 MLE Pd and 1 MLE Au at 298 K followed by annealing to 573 K results in a bimetallic core and Pd shell, with TiOx encapsulation on annealing to ~ 800 K. Further deposition of Au on the pinwheel type TiOx layer results in a template-assisted nucleation of Au nanoclusters, while on the zigzag type TiOx layer no preferential adsorption site of Au was observed. Increasing the Au:Pd ratio to 3 MLE Pd and 2 MLE Au results in nanoparticles that are enriched in Au at their surface, which exhibit a strong resistance towards encapsulation. Hence the degree of encapsulation of the nanoparticles during sintering can be controlled by tuning the Au:Pd ratio.
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Affiliation(s)
- Richard Gubó
- Department of Applied and Environmental Chemistry, University of Szeged, Rerrich B. tér 1., 6720 Szeged, Hungary
- ELI-HU Nonprofit Kft, Extreme Light Infrastructure-ALPS, Dugonics tér 13, 6720 Szeged, Hungary
| | - Chi M. Yim
- London Centre for Nanotechnology and Chemistry Department, University College London, 20 Gordon Street, London, WC1H 0AJ UK
| | - Michael Allan
- London Centre for Nanotechnology and Chemistry Department, University College London, 20 Gordon Street, London, WC1H 0AJ UK
| | - Chi L. Pang
- London Centre for Nanotechnology and Chemistry Department, University College London, 20 Gordon Street, London, WC1H 0AJ UK
| | - András Berkó
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group, Rerrich B. tér 1., 6720 Szeged, Hungary
| | - Geoff Thornton
- London Centre for Nanotechnology and Chemistry Department, University College London, 20 Gordon Street, London, WC1H 0AJ UK
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Demiroglu I, Li Z, Piccolo L, Johnston RL. A DFT study of molecular adsorption on titania-supported AuRh nanoalloys. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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6
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Piccolo L, Li ZY, Demiroglu I, Moyon F, Konuspayeva Z, Berhault G, Afanasiev P, Lefebvre W, Yuan J, Johnston RL. Understanding and controlling the structure and segregation behaviour of AuRh nanocatalysts. Sci Rep 2016; 6:35226. [PMID: 27739480 PMCID: PMC5064371 DOI: 10.1038/srep35226] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/23/2016] [Indexed: 12/19/2022] Open
Abstract
Heterogeneous catalysis, which is widely used in the chemical industry, makes a great use of supported late-transition-metal nanoparticles, and bimetallic catalysts often show superior catalytic performances as compared to their single metal counterparts. In order to optimize catalyst efficiency and discover new active combinations, an atomic-level understanding and control of the catalyst structure is desirable. In this work, the structure of catalytically active AuRh bimetallic nanoparticles prepared by colloidal methods and immobilized on rutile titania nanorods was investigated using aberration-corrected scanning transmission electron microscopy. Depending on the applied post-treatment, different types of segregation behaviours were evidenced, ranging from Rh core – Au shell to Janus via Rh ball – Au cup configuration. The stability of these structures was predicted by performing density-functional-theory calculations on unsupported and titania-supported Au-Rh clusters; it can be rationalized from the lower surface and cohesion energies of Au with respect to Rh, and the preferential binding of Rh with the titania support. The bulk-immiscible AuRh/TiO2 system can serve as a model to understand similar supported nanoalloy systems and their synergistic behaviour in catalysis.
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Affiliation(s)
- Laurent Piccolo
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256 CNRS &Université Claude Bernard - Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne, France
| | - Z Y Li
- Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Ilker Demiroglu
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, United Kingdom
| | - Florian Moyon
- Normandie Université, UNIROUEN, INSA Rouen, CNRS, Groupe de Physique des Matériaux, 76000, Rouen, France
| | - Zere Konuspayeva
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256 CNRS &Université Claude Bernard - Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne, France
| | - Gilles Berhault
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256 CNRS &Université Claude Bernard - Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne, France
| | - Pavel Afanasiev
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), UMR 5256 CNRS &Université Claude Bernard - Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne, France
| | - Williams Lefebvre
- Normandie Université, UNIROUEN, INSA Rouen, CNRS, Groupe de Physique des Matériaux, 76000, Rouen, France
| | - Jun Yuan
- Department of Physics, University of York, York, YO10 5DD, United Kingdom
| | - Roy L Johnston
- School of Chemistry, University of Birmingham, Birmingham B15 2TT, United Kingdom
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Demiroglu I, Li ZY, Piccolo L, Johnston RL. A DFT study of molecular adsorption on Au–Rh nanoalloys. Catal Sci Technol 2016. [DOI: 10.1039/c6cy01107a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Density functional theory calculations are performed to investigate both mixing and adsorption properties of 38-atom and 79-atom Au–Rh nanoalloys at the nanoscale.
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Affiliation(s)
- Ilker Demiroglu
- School of Chemistry
- University of Birmingham
- Birmingham B15 2TT
- UK
| | - Z. Y. Li
- Nanoscale Physics Research Laboratory
- School of Physics and Astronomy
- University of Birmingham
- Birmingham B15 2TT
- UK
| | - Laurent Piccolo
- Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON)
- UMR 5256 CNRS & Université Claude Bernard Lyon 1
- F-69626 Villeurbanne
- France
| | - Roy L. Johnston
- School of Chemistry
- University of Birmingham
- Birmingham B15 2TT
- UK
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Óvári L, Berkó A, Vári G, Gubó R, Farkas AP, Kónya Z. The growth and thermal properties of Au deposited on Rh(111): formation of an ordered surface alloy. Phys Chem Chem Phys 2016; 18:25230-25240. [PMID: 27711369 DOI: 10.1039/c6cp02128j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Scanning tunnelling microscopy (STM), low energy ion scattering spectroscopy (LEIS), X-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy (HREELS) were applied for studying Au deposited on the Rh(111) surface.
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Affiliation(s)
- László Óvári
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
| | - András Berkó
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
| | - Gábor Vári
- Department of Applied and Environmental Chemistry
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Richárd Gubó
- Department of Applied and Environmental Chemistry
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Arnold Péter Farkas
- Department of Physical Chemistry and Materials Science
- University of Szeged
- H-6720 Szeged
- Hungary
| | - Zoltán Kónya
- MTA-SZTE Reaction Kinetics and Surface Chemistry Research Group
- H-6720 Szeged
- Hungary
- Department of Applied and Environmental Chemistry
- University of Szeged
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9
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Berkó A, Gubó R, Óvári L, Kónya Z. Rh and Au deposited on ultrathin TiO~1.2 film formed on Rh(111) facets and the effects of CO exposure. SURFACE SCIENCE 2015. [DOI: 10.1016/j.susc.2015.02.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Konuspayeva Z, Afanasiev P, Nguyen TS, Di Felice L, Morfin F, Nguyen NT, Nelayah J, Ricolleau C, Li ZY, Yuan J, Berhault G, Piccolo L. Au–Rh and Au–Pd nanocatalysts supported on rutile titania nanorods: structure and chemical stability. Phys Chem Chem Phys 2015; 17:28112-20. [DOI: 10.1039/c5cp00249d] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Au–Rh and Au–Pd nanoalloys synthesized by colloidal methods and immobilized on rutile titania nanorods are more stable than their monometallic counterparts for tetralin hydrogenation in the presence of sulfur.
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11
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Gubó R, Óvári L, Kónya Z, Berkó A. Growth of Gold on a Pinwheel TiO∼1.2 Encapsulation Film Prepared on Rhodium Nanocrystallites. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14545-54. [PMID: 25417893 DOI: 10.1021/la503756c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- R. Gubó
- Department
of Applied and Environmental Chemistry, University of Szeged, 6720 Szeged, Rerrich Béla tér
1, Hungary
| | - L. Óvári
- MTA-SZTE Reaction
Kinetics and Surface Chemistry Research Group, 6720 Szeged, Rerrich Béla
tér 1, Hungary
| | - Z. Kónya
- Department
of Applied and Environmental Chemistry, University of Szeged, 6720 Szeged, Rerrich Béla tér
1, Hungary
- MTA-SZTE Reaction
Kinetics and Surface Chemistry Research Group, 6720 Szeged, Rerrich Béla
tér 1, Hungary
| | - A. Berkó
- MTA-SZTE Reaction
Kinetics and Surface Chemistry Research Group, 6720 Szeged, Rerrich Béla
tér 1, Hungary
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