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Plyasova, L. M.; Molina, I. Yu.; Cherepanova, Svetlana V.; Рудина, Н. А.; Sherstyuk, O. V.; Savinova, Elena R.; Pronkin, Sergey; Tsirlina, Galina A.

doi:10.1023/a:1020607904477

Cited by 13 publications

(2 citation statements)

References 4 publications

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“…22 The result of secondary nucleation is formation of complex micro-and nanograined Pt structures. 3,22,23 On atomically smooth HOPG surface formation of particle agglomerates may also occur through migration and coalescence of Pt nanoparticles favoured by weak interaction of Pt with HOPG substrate. Hence, Gloaguen et al 20 and Lee et al 24 conclude that Pt electrodeposition on HOPG occurs via formation of particles 10-20 nm in diameter and, as the deposition time increases, subsequent surface diffusion sticking together individual nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

Influence of particle agglomeration on the catalytic activity of carbon-supported Pt nanoparticles in CO monolayer oxidation

Maillard¹,

Schreier²,

Hanzlik³

et al. 2005

Phys. Chem. Chem. Phys.

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416

369

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International audienceFuel cell electrocatalysts usually feature high noble metal contents, and these favour particle agglomeration. In this paper a variety of synthetic approaches (wet chemical deposition, electrodeposition and electrodeposition on chemically preformed Pt nuclei) is employed to shed light on the influence of nanoparticle agglomeration on their electrocatalytic properties. Pt loading on model glassy carbon (GC) support is increased systematically from 1.8 to 10.6 µg Pt cm^–2 and changes in the catalyst structure are followed by transmission electron microscopy. At low metal loadings (≤5.4 µg Pt cm^–2) isolated single crystalline Pt nanoparticles are formed on the support surface by wet chemical deposition from H₂PtCl₄ precursor. An increase in the metal loading results, first, in a systematic increase of the average diameter of isolated Pt nanoparticles and, second, in coalescence of nanoparticles and formation of particle agglomerates. This behaviour is in line with the previous observations on carbon-supported noble metal fuel cell electrocatalysts. The catalytic activity of Pt/GC electrodes is tested in CO monolayer oxidation. In agreement with the previous studies (F. Maillard, M. Eikerling, O. V. Cherstiouk, S. Schreier, E. Savinova and U. Stimming, Faraday Discuss., 2004, 125, 357), we find that the reaction is strongly size sensitive, exhibiting an increase of the reaction overpotential as the particle size decreases below ca. 3 nm. At larger particle sizes the dependence levels off, the catalytic activity of particles with diameters above 3 nm approaching that of polycrystalline Pt. Meanwhile, Pt agglomerates show remarkably enhanced catalytic activity in comparison to either isolated Pt nanopraticles or polycrystalline Pt foil, catalysing CO monolayer oxidation at ca. 90 mV lower overpotential. Enhanced catalytic activity of Pt agglomerates is ascribed to high concentration of surface defects. CO stripping voltammograms from Pt/GC electrodes, comprising Pt agglomerates along with isolated single crystalline Pt nanoparticles from 2 to 6 nm size, feature double voltammetric peaks, the more negative corresponding to CO oxidation on Pt agglomerates, while the more positive to CO oxidation on isolated Pt nanoparticles. It is shown that CO stripping voltammetry provides a fingerprint of the particle size distribution and the extent of particle agglomeration in carbon-supported Pt catalysts

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Section: Resultsmentioning

confidence: 99%

Influence of particle agglomeration on the catalytic activity of carbon-supported Pt nanoparticles in CO monolayer oxidation

Maillard¹,

Schreier²,

Hanzlik³

et al. 2005

Phys. Chem. Chem. Phys.

Self Cite

416

369

View full text Add to dashboard Cite

show abstract

“…2) must substantially prevail over the peak corresponding to the oxidation of pairs CO ads +Ag ad . The formation of "islets" of silver of smaller dimensions on Pt/Pt as compared with smPt is realistic to expect in view of a higher defectness of the structure of Pt/Pt [28,29]. This may lead to the presence of a large number of "centers" of two-dimensional aggregation of silver on Pt/Pt.…”

Section: Resultsmentioning

confidence: 99%

Specific Features of the Adsorption of Carbon Monoxide on a Smooth Polycrystalline Platinum Electrode Modified with Adsorbed Silver Atoms

2005

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The adsorption of carbon monoxide at the surface of smooth polycrystalline platinum (smPt) is studied in conditions of a preliminary accumulation of various quantities of silver ( θ Ag ) on the surface. A comparison with similar data obtained previously for Pt/Pt is conducted. It is discovered that on smPt, exactly as in the case of Pt/Pt, carbon monoxide undergoes adsorption at sites that are not occupied by adsorbed silver, without forcing the preliminarily adsorbed silver out. At small and intermediate Ag ad , as opposed to Pt/Pt, a mere two peaks are observed in a voltametric curve in the region of electrodesorption of the mixed layer on smPt. It is shown that, in the region of potentials of the first peak, there occurs practically no transition of silver into solution in the course of oxidation of the mixed layer. Specific features that characterize the behavior of the CO ads + Ag ad mixed layer are discussed under the assumption about an "islet" character of the adsorption of silver.

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Mutual indirect probing of platinized platinum/tungstate nanostructural features

Timofeeva

Borzenko

Tsirlina

et al. 2004

J Solid State Electrochem

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Cited by 13 publications

References 4 publications

Influence of particle agglomeration on the catalytic activity of carbon-supported Pt nanoparticles in CO monolayer oxidation

Influence of particle agglomeration on the catalytic activity of carbon-supported Pt nanoparticles in CO monolayer oxidation

Specific Features of the Adsorption of Carbon Monoxide on a Smooth Polycrystalline Platinum Electrode Modified with Adsorbed Silver Atoms

Mutual indirect probing of platinized platinum/tungstate nanostructural features

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