Oxidation of the polycrystalline gold foil surface and XPS study of oxygen states in oxide layers

Stadnichenko, A. I.; Кощеев, С. В.; Boronin, A. I.

doi:10.3103/s0027131407060090

Cited by 56 publications

(26 citation statements)

References 22 publications

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“…The fact that this peak is not observed for In 2 O 3 nanoparticles implies the presence of chemically reactive Au species on the surface of the mixed Au-In oxide. This picture finds support in a recent XPS study on Au oxidation in high-frequency discharges, which showed a similar high-energy O 1s peak after long exposure of Au to oxygen (42,43).…”

Section: Resultssupporting

confidence: 66%

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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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Section: Resultssupporting

confidence: 66%

“…Fig. 3D (42). Our XPS measurements were carried out on samples that had been annealed to temperatures (473 K) sufficient to desorb weakly bound species.…”

Section: Resultsmentioning

confidence: 99%

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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“…Noticeable differences can be seen between the two types of NFs in terms of peak position as well as the peak shape for both the O1s and Ni2p 3/2 transitions. In the O1s spectra for calcined NFs, the peak is shifted to lower binding energy (BE) of about 528 eV followed by a low intensity peak at 530 eV which suggests that the charge state of O is closer to that of atomic O and that O exists in multiple oxidation states [54,55]. In case of annealed NFs, the O1s peak lies at nearly 530 eV which corresponds to fully bonded lattice O with oxidation state of -2 [56].…”

Section: Page 17 Of 28mentioning

confidence: 89%

Electrospun nickel oxide nanofibers: Microstructure and surface evolution

Khalil¹,

Hashaikeh²

2015

Applied Surface Science

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“…According to the study of isomorphic Au in argentite, the chemical shift of Au (I) peak Au 4f 7/2 is 0.7-0.8 eV [24]. In the case of P-4581 and P-5707 samples it is noticeably higher (1.0-1.8 eV) and possibly corresponds to trivalent gold compounds of gold (at least for the last sample) [4,25]. Thus, according to XPS data, the high-fineness Au of the deposit belonging to relatively high-temperature mesothermal Au-Sulf-Q ore formation does not contain oxidized Au components on the surface, whereas lower fineness gold of epithermal gold-silver deposits, mostly present as electrum, in 50% of cases contains oxidized gold.…”

Section: Xps and Aes Datamentioning

confidence: 99%

Contrasting Surficial Composition of Native Gold from Two Different Types of Gold Ore Deposits

et al. 2017

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Native gold grains sampled at two different gold ore deposits in Eastern Russia have been studied by the techniques of electron spectroscopy (X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES)), electron microprobe analysis (EMPA), and scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX). The high-fineness gold of the deposit hosted by relatively high temperature gold-quartz-sulfide mesothermal ore formation contains no oxidized Au constituents on grain surfaces, whereas the less fine gold of the epithermal Au-Ag deposit contains gold oxidized to the Au (I) state, or higher, in half of the cases. At this deposit the surface of native Au consists of a thin layer (~15 nm) with elevated Ag and S contents and an underlying SiO 2 -containing layer~30-60 nm thick. Such a composite coating can perform a protective function and prevent the gold-silver sulfides in surficial parts of AuAg grains from oxidation. The sulfur-enriched marginal parts of native gold particles do not always correlate with the stoichiometry of well-known binary AuAg-sulfides and have a variable composition. This may be due to the existence of solid solutions, Ag 2−x Au x S, if there is enough S or S adsorption-stabilized cluster agglomerates, Ag n Au m S, under sulfur deficit. The effect of the formation of nano-scale surficial zonality on the surface of native gold is quite common in nature and applicable to geological exploration and technology of gold-ore processing. It can facilitate establishing the geochemical environment and genetic type of Au mineralization.

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Oxidation of the polycrystalline gold foil surface and XPS study of oxygen states in oxide layers

Cited by 56 publications

References 22 publications

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

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

Electrospun nickel oxide nanofibers: Microstructure and surface evolution

Contrasting Surficial Composition of Native Gold from Two Different Types of Gold Ore Deposits

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