Catalytically highly active top gold atom on palladium nanocluster

Zhang, Haijun; Watanabe, Teiji; Okumura, Mitsutaka; Haruta, Masatake; Toshima, Naoki

doi:10.1038/nmat3143

Cited by 580 publications

(489 citation statements)

References 29 publications

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“…Thus, our calculations clearly manifest that Au atoms preferentially remain on the surface by the segregation process; this will mend the defective sites on the Pt monolayers and, thus, markedly inhibit the Pd and Pt dissolution. Recent observations that preferential replacement of Au atoms takes place at the vertex or corner sites on Pd nanoparticle surfaces (1.8 nm diameter) 19 may also support our results. Accordingly, the stability of Pt ML /Pd 9 Au 1 /C under fuelcell conditions may be augmented through the inhibition of Pd dissolution.…”

Section: Structure Of Pt ML /Pdau/c Electrocatalystsupporting

confidence: 90%

Highly stable Pt monolayer on PdAu nanoparticle electrocatalysts for the oxygen reduction reaction

et al. 2012

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stability is one of the main requirements for commercializing fuel cell electrocatalysts for automotive applications. Platinum is the best-known catalyst for oxygen reduction in cathodes, but it undergoes dissolution during potential changes while driving electric vehicles, thus hampering commercial adoption. Here we report a new class of highly stable, active electrocatalysts comprising platinum monolayers on palladium-gold alloy nanoparticles. In fuel-cell tests, this electrocatalyst with its ultra-low platinum content showed minimal degradation in activity over 100,000 cycles between potentials 0.6 and 1.0 V. under more severe conditions with a potential range of 0.6-1.4 V, again we registered no marked losses in platinum and gold despite the dissolution of palladium. These data coupled with theoretical analyses demonstrated that adding a small amount of gold to palladium and forming highly uniform nanoparticle cores make the platinum monolayer electrocatalyst significantly tolerant and very promising for the automotive application of fuel cells.

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Section: Structure Of Pt ML /Pdau/c Electrocatalystsupporting

confidence: 90%

Highly stable Pt monolayer on PdAu nanoparticle electrocatalysts for the oxygen reduction reaction

et al. 2012

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“…The 3D atomic arrangement on the surface and in the core of a nanocrystal influences the electronic structure, which affects how the nanocrystal functions in catalysis or how it interacts with other components at the atomic scale (1). Introduction of atomic dopants, surface adatoms, defects, and grain boundaries alters the chemical properties of nanocrystals (2). Ensembles of synthesized nanocrystals in solution are structurally inhomogeneous due to the stochastic nature of nanocrystal nucleation and growth (3,4).…”

Section: Main Textmentioning

confidence: 99%

3D structure of individual nanocrystals in solution by electron microscopy

Park

Elmlund

Ercius

et al. 2015

Science

283

252

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Abstract:Understanding structural details of colloidal nanoparticles is required to bridge our knowledge about their synthesis, growth mechanisms, and physical properties. We introduce a method for determining 3D structures of individual nanoparticles in solution.We combine a graphene liquid cell, high-resolution transmission electron microscopy, a direct electron detector, and an algorithm for single-particle 3D reconstruction originally developed for analysis of biological molecules to produce two near-atomic resolution 3D structures of individual Pt nanocrystals. Since our method derives the 3D structure from images of individual nanoparticles rotating freely in solution, it enables the analysis of heterogeneous populations of potentially unordered nanoparticles that are synthesized in solution, thereby providing a means to understand the structure and stability of defects at the nanoscale. Main Text:Colloidal nanoparticles are clusters of hundreds to thousands of inorganic atoms typically surrounded by organic ligands that stabilize them in solution. The atomic arrangement of colloidal nanoparticles determines their chemical and physical properties, which are distinct from bulk materials and can be exploited for many applications in biological imaging, renewable energy, catalysis, and more. The 3D atomic arrangement on the surface and in the core of a nanocrystal influences the electronic structure, which affects how the nanocrystal functions in catalysis or how it interacts with other components at the atomic scale (1). Introduction of atomic dopants, surface adatoms, defects, and grain boundaries alters the chemical properties of nanocrystals (2). Ensembles of synthesized nanocrystals in solution are structurally inhomogeneous due to the stochastic nature of nanocrystal nucleation and growth (3,4). Therefore, a method for determination of the 3D atomic arrangement of individual unique nanoparticles in solution is needed. 3Electron tomography is routinely used for 3D analysis of materials (5-9). This method cannot be applied to individual particles in a liquid because it relies on acquisition of images of a single object at many different tilt angles over 2 to 5 hours, assuming the object is static during the entire acquisition. Single particle cryo-electron microscopy (cryo-EM) is a common method for the determination of 3D structures in biological sciences. The average 3D Coulomb potential map (density) of a protein is reconstructed from tens of thousands of TEM images of randomly oriented copies of the same protein embedded in vitreous ice (10). The unknown 3D projection angles of the images are determined by computational methods (11). Single-particle cryo-EM has succeeded in reconstructing biological molecules with nearly 3 Å resolution (10, 12). A similar approach was recently applied to reconstruct the atomic structure of homogeneous ultrasmall gold clusters (13). However, the single-particle method is not readily applicable to 3D reconstruction of colloidal nanoparticles due to their intrinsic struc...

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“…[10][11][12][13][14] Apart from the strong size dependence of the catalytic activity of gold clusters one of the most important factors in gold nanocatalysis is the support effect. 15,16 It was demonstrated that the so-called active metal oxide supports (such as, MgO, TiO 2 , Al 2 O 3 , Fe 2 O 3 , etc.)…”

Section: Introductionmentioning

confidence: 99%

CO oxidation on h-BN supported Au atom

Gao

Lyalin

Taketsugu

2013

The Journal of Chemical Physics

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The mechanism of CO oxidation by O 2 on Au atoms supported on the pristine and defected hexagonal boron nitride (h-BN) surface has been studied theoretically using density functional theory. It is found that O 2 binds stronger than CO on an Au atom supported on the defect free h-BN surface and h-BN surface with nitrogen vacancy (V N @h-BN), but weaker than CO on a free Au atom or Au trapped by a boron vacancy (V B @h-BN). The excess of the positive or negative charge on Au can considerably change its catalytic properties and enhance activation of the adsorbed O 2 . Coadsorption of CO and O 2 on Au, Au/V N @h-BN, and Au/V B @h-BN results in additional charge transfer to O 2 . Various pathways of the CO oxidation reaction by molecular oxygen are studied. We found two different pathways for CO oxidation: a two-step pathway where two CO 2 molecules are formed independently, and a self-promotion pathway where oxidation of the first CO molecule is promoted by the second CO molecule. Interaction of Au with the defect-free and defected h-BN surface considerably affects the CO oxidation reaction pathways and barriers. Therefore, Au supported on the h-BN surface (pristine or defected) cannot be considered as pseudo-free atom and support effects have to be taken into account, even when the interaction of Au with the support is weak.

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Catalytically highly active top gold atom on palladium nanocluster

Cited by 580 publications

References 29 publications

Highly stable Pt monolayer on PdAu nanoparticle electrocatalysts for the oxygen reduction reaction

Highly stable Pt monolayer on PdAu nanoparticle electrocatalysts for the oxygen reduction reaction

3D structure of individual nanocrystals in solution by electron microscopy

CO oxidation on h-BN supported Au atom

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