Molecular Spectroscopy by Means of ESCA III.<i>Carbon compounds</i>

Gelius, U.; Hedén, Per Filip; Hedman, J.; Lindberg, B.; Manne, Rolf; Nordberg, Ragnar; Nordling, C.; Siegbahn, Kai

doi:10.1088/0031-8949/2/1-2/014

Cited by 594 publications

(238 citation statements)

References 33 publications

Supporting

Mentioning

205

Contrasting

Unclassified

Order By: Relevance

“…It is reasonable to associate C 2 , detected after exposure to CO and O 2 at 100 K, to the presence of CO on the surface. Gas phase CO has a BE ∼290 eV (45), but chemisorption of CO on oxides leads to significant (>3 eV) broadening of the peak and shifts in the BE (46), consistent with our observation (Fig. 5B) should be shifted to higher energies compared with CO (45).…”

Section: Resultssupporting

confidence: 89%

“…Following the adsorption, the C 1s spectrum of the nanoparticles shows two peaks: C 1 , BE ∼285 eV, and a relatively weak C 2 , BE ∼288.5 eV. C 1 was present after prolonged initial annealing at 473 K, before adsorption of gases, and persists throughout our experiments; it is consistent with the presence of carbon or hydrocarbons on the surface (44,45). It is reasonable to associate C 2 , detected after exposure to CO and O 2 at 100 K, to the presence of CO on the surface.…”

Section: Resultssupporting

confidence: 73%

See 1 more Smart Citation

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.

View full text Add to dashboard Cite

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 ...

show abstract

Section: Resultssupporting

confidence: 89%

Section: Resultssupporting

confidence: 73%

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.

View full text Add to dashboard Cite

show abstract

“…5 The C Is spectrum at the top of Figure 5 (b) is rather complex, showing a weak carbide feature at 283.5 eV, strong hydrocarbon-related features near 285 and 286 eV, 12 and a significant peak near 289 eV. The 289 eV C peak is near the expected binding energy for a carboxylate species, 24 lending support to the above assignment of the Pb peaks as unreacted Pbnp. Therefore, the 139.2 eV Pb 4f7/2 binding energy and the existence of a strong carboxylate peak will be used diagnostically to indicate unreacted physisorbed Pbnp.…”

Section: 000mentioning

confidence: 53%

Chemistry of the extreme-pressure lubricant additive lead naphthenate on steel surfaces

Didziulis¹,

Fleischauer²

1991

Langmuir

View full text Add to dashboard Cite

The adsorption and chemical reactivity of the extreme-pressure (EP) oil additive lead naphthenate (Pbnp) on steel surfaces are examined with X-ray photoelectron spectroscopy. In addition, the chemical compositions of AISI 440C and 52100 steel surfaces are studied as a function of sample cleaning treatment, including solvent cleaning, and treatments with acidic and basic solutions. At room temperature, Pbnp is shown to physisorb on the iron oxide overlayer present on both steel surfaces following solvent cleaning. A chemisorbed form of Pbnp is characterized by Pb 4f peaks chemically shifted by 0.3-0.4 eV to lower binding energy and significantly lower intensity of the C Is feature associated with the Pbnp carboxylate group. This form of Pbnp is observed on acid-and base-pretreated surfaces that lose their iron oxide overlayers. The chemisorbed Pbnp surface species is also observed when the steel surfaces are scratched while being immersed in the Pbnp solution. When the Pbnp treated steel surfaces are heated to simulate the EP conditions for which Pbnp is used, most of the Pbnp on the oxide-covered surfaces desorbs. In addition, metallic Pb is readily formed on the scratched surfaces and on surfaces with significant amounts of metallic Fe. These results point to two possible modes of boundary protection: chemisorbed Pbnp under mild wear conditions and a layer of metallic Pb under severe wear conditions.

show abstract

“…21 In Fig. 3, the major peaks expected from nucleobases are present in the C 1s feature of DNA, i.e., urea ͑peak 1͒, amide ͑2͒, carbon bond to nitrogen ͑3͒, and hydrocarbon ͑4͒.…”

Section: B Xps Characterization Of Dnamentioning

confidence: 99%

X-ray induced damage in DNA monitored by X-ray photoelectron spectroscopy

Ptasińska¹,

Stypczyńska²,

Nixon³

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy ͑XPS͒. The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different sites. We show that from a comparative analysis of the modification in XPS line shapes of the C 1s, O 1s, N 1s, and P 2p peaks, one can gain insight into a number of reaction pathways leading to radiation damage to DNA.

show abstract

Molecular Spectroscopy by Means of ESCA III.Carbon compounds

Cited by 594 publications

References 33 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

Chemistry of the extreme-pressure lubricant additive lead naphthenate on steel surfaces

X-ray induced damage in DNA monitored by X-ray photoelectron spectroscopy

Contact Info

Product

Resources

About