Equations for the Cabrera–Mott kinetics of oxidation for spherical nanoparticles

Ermoline, Alexandre; Dreizin, Edward L.

doi:10.1016/j.cplett.2011.02.022

Cited by 66 publications

(56 citation statements)

References 16 publications

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“…% Au (Fig. 1E), close to Au 3 In alloy inferred from the DPs, whereas the In-rich nanoparticles (Fig. 2F) show Au in the range of 32-35 at.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast to the oxidation of In nanoparticles under similar conditions (2,5), which results in crystalline In 2 O 3 shells (2), for Au-In alloy nanoparticles the oxide shells are amorphous, i.e., show no crystalline order. Statistical analysis (for ∼50 particles per sample) shows a uniform thickness of the oxide shells of 1.6 ± 0.4 nm for Au 3 In and 2.3 ± 0.4 nm for AuIn 2 nanoparticles. The thicker oxide of the In-rich particles allows reliable EDS analysis of the shell composition, which shows a Au:In ratio close to the one of the core (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…3 B-D) and AuIn 2 nanoparticles reveals the presence of Au, In, and O. We focus the further analysis on the Au-rich Au 3 In alloy. Here, the Au 4f peaks are broadened and their center shifted to higher binding energy (BE) compared with a Au reference (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1B, left side) because the field of view encompasses several particles with random orientation. The DPs consist of discrete spots on rings that are readily indexed to the orthorhombic Au 3 In phase (29) for the sample with high Au content (Fig. 1B, right side: calculated DP).…”

Section: Resultsmentioning

confidence: 99%

“…Most of this insight should apply directly to the oxidation of nanoparticles, but important aspects arise in the geometry of small particles. For example, the high curvature in a nanoparticle can drive oxidation to larger thicknesses than in the planar case (2)(3)(4). Nanoscale junctions and interfaces to other materials can promote enhanced oxidation, as well as the formation of well-ordered epitaxial oxide segments (5).…”

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confidence: 99%

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Oxidation of nanoscale Au–In alloy particles as a possible route toward stable Au-based catalysts

Sutter

Tong

Jungjohann

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The oxidation of bimetallic alloy nanoparticles comprising a noble and a nonnoble metal is expected to cause the formation of a single-component surface oxide of the nonnoble metal, surrounding a core enriched with the noble metal. Studying the room temperature oxidation of Au-In nanoparticles, we show that this simple picture does not apply to an important class of bimetallic alloys, in which the oxidation proceeds via predominant oxygen diffusion. Instead of a crystalline In 2 O 3 shell, such oxidation leads to an amorphous shell of mixed Au-In oxide that remains stable to high temperatures and whose surface layer is enriched with Au. The Au-rich mixed oxide is capable of adsorbing both CO and O 2 and converting them to CO 2 , which desorbs near room temperature. The oxidation of Au-In alloys to a mixed Au-In oxide shows significant promise as a viable approach toward Au-based oxidation catalysts, which do not require any complex synthesis processes and resist deactivation up to at least 300°C.transmission electron microscopy | temperature programmed desorption | X-ray photoelectron spectroscopy T he importance of metal nanoparticles for a wide variety of applications, e.g., in catalysis, sensing, etc., has sparked interest in understanding and controlling their oxidation. The formation of an oxide layer negatively affects performance in applications that require pure metal surfaces. However, oxidation can be advantageous as it opens a way for engineering complex structures. Our understanding of room temperature oxidation has been established primarily in studies on the oxidation of bulk materials or planar films (1). Most of this insight should apply directly to the oxidation of nanoparticles, but important aspects arise in the geometry of small particles. For example, the high curvature in a nanoparticle can drive oxidation to larger thicknesses than in the planar case (2-4). Nanoscale junctions and interfaces to other materials can promote enhanced oxidation, as well as the formation of well-ordered epitaxial oxide segments (5). The oxidation of nanoparticles is also a powerful mechanism to produce nanoscale heterostructures. Metals that oxidize via predominant anion diffusion [In (2, 5), Pb (6), Sn, among others] form metal-oxide core-shell nanoparticles. For metals that oxidize via fast cation diffusion [Co (7), Al (6), Fe (8), Ni (9), among others], nanoscale porosity buildup creates hollow oxide nanocrystals that can be used as cages, e.g., to be filled with different materials (7) for storage or protection.Bimetallic (alloy, core-shell, etc.) nanoparticles promise widely tunable properties, and much progress has recently been made in their controlled synthesis (10). The oxidation of bimetallic nanoparticles has been studied much less than that of elemental metals, but it could provide even more interesting opportunities for the fabrication of functional nanomaterials, for example in catalysis.Alloys that comprise a noble and a less noble metal component are of interest because their oxidation can give ...

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“…% Au (Fig. 1E), close to Au 3 In alloy inferred from the DPs, whereas the In-rich nanoparticles (Fig. 2F) show Au in the range of 32-35 at.…”

Section: Resultsmentioning

confidence: 99%