Study of the L2,3 edges of 3d transition metals by X-ray absorption spectroscopy

Akgül, Güvenç; Aksoy, Funda; Bozduman, A.; Özkendir, Osman Murat; Ufuktepe, Y.; Lüning, J.

doi:10.1016/j.tsf.2008.08.173

Cited by 21 publications

(11 citation statements)

References 28 publications

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“…18 Measurements at the Cu L 3;2 -edge on similar materials has been shown to provide a spectroscopic signature for the Cu oxidation state in the materials. 19 As our Cu L 3;2 -edge measurements agree with our previous measurements, 17 Figure 1 plots XANES spectra at the Cd M 3 -edge for CdSe QDs as a function of Cu dopant concentration; included in this plot is the corresponding bulk spectrum for undoped CdSe. It has been shown that the Cd L 3 -edge can probe changes that occur near the bottom of the CB as the dipole selection rules dictate sensitivity between the 2p initial state and the final states of s and d character.…”

supporting

confidence: 87%

Modification of the conduction band edge energy via hybridization in quantum dots

Wright¹,

Meulenberg²

2012

Appl. Phys. Lett.

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supporting

confidence: 87%

Modification of the conduction band edge energy via hybridization in quantum dots

Wright¹,

Meulenberg²

2012

Appl. Phys. Lett.

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“…Electron escape depth measurements are generally estimated by photo‐emitted and Auger electrons only for the specific samples . In the last several years, renewed interest in XAS has demanded a better understanding of the TEY measurements of 3d metals that have been used in many recent studies . Much of this research involves estimating the escape depth of the emitted electrons.…”

Section: Introductionmentioning

confidence: 99%

“…[16,17] In the last several years, renewed interest in XAS has demanded a better understanding of the TEY measurements of 3d metals that have been used in many recent studies. [3,6,7,18,19] Much of this research involves estimating the escape depth of the emitted electrons.…”

Section: Introductionmentioning

confidence: 99%

Thickness and angular dependence of the L‐edge X‐ray absorption of nickel thin films

et al. 2011

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We report on the near‐edge X‐ray absorption fine structure spectroscopy of the L3 (2p3/2) and L2 (2p1/2) edges for ferromagnetic pure nickel transition metal and show that the L2,3 edge peak intensity and satellite feature at ~6 eV above the L3 edge in nickel increase with increasing nickel film thickness both in the total electron yield and transmission modes. The absorption spectra of nickel metal, however, exhibit strong angular‐dependent effects when measured in total electron yield mode. In addition, we calculated the mean electron escape depth of the emitted electrons (λe), which was found for pure nickel metal to be λe=25 ± 2 Å. We point out the advantages of the total electron yield technique for the study of the L‐edge of 3d transition metals. Copyright © 2011 John Wiley & Sons, Ltd.

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“…This is usually the case for L-edge absorption of 1st row (3d) transition metals such as Mn, Fe and Co; M-edge absorption of 2nd row (4d) transition metals; and N-edge absorption of 3rd row (5d) transition metals. For instance, X-rays with photon energies of the Co L 3 step edge have attenuation lengths of 800 nm, defined as the length for a drop of intensity by 1/e, while electron yields are entirely registered from the topmost 2.5 nm of surfaces [15]. Furthermore, simultaneous measurement of X-ray emission provides the complimentary bulk detection.…”

Section: Electronic Chemical and Crystallographicmentioning

confidence: 99%

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

Alayoǧlu

Somorjai

2014

Catal Lett

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Model nano-catalysts with monodisperse particle sizes and architectures are essential for a fundamental understanding of surface property dynamics during catalytic reactions. Surface tools and techniques, when conducted under catalytically relevant temperature and pressure conditions, render possible measurements of dynamic surface properties such as oxidation state, composition, coordination, and bonding. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy with purposely built in situ reaction cells and ambient pressure X-ray photoelectron spectroscopy (APXPS) provide (near) surface sensitive and chemical specific information on the oxidation states of metal and oxide (co-)catalysts as well as adsorbent functional elements such C, O and N under reactive gas atmospheres and even liquid environments. Likewise, sum frequency generation (SFG) vibrational spectroscopy with in situ reaction cells helps uncover the bonding geometry and configuration of the topmost surface again under conditions pertinent to catalysis. Furthermore, the local dynamics in the nanoscale and on the single particle level are revealed by environmental transmission electron microscopy (ETEM) and the spectro-microscopy techniques equipped within. A correlative approach, where an array of these in situ tools and techniques were conducted in parallel with catalytic measurements, was employed to gain molecular insight into some of the modern scientific challenges in heterogeneous catalysis.Several case examples of this correlative approach are presented here. The CO oxidation reaction over hybrid nano-catalysts of Pt nanoparticles (NPs) with various mesoporous metal oxides such as Co 3 O 4 , MnO 2 and CeO 2 was explored in relation to bifunctional catalysis and interfacial charge transfer chemistry by using in situ NEXAFS spectroscopy. Likewise, bimetallic CoPt and PtSn nanoparticle catalysts supported on silica were investigated by using a combination of in situ NEXAFS spectroscopy and APXPS. Next, CO 2 hydrogenation was carried out over bimetallic CoPt/SiO 2 and Co/TiO 2 hybrid nano-catalysts. In this case, in situ NEXAFS spectroscopy, APXPS, and ETEM indicated severe, yet reversible, surface restructuring that involved hydrogen atom spillover. Finally, *2 nm Pt NPs were investigated using in situ SFG to study hydrogenation and hydrogenative isomerization reactions. Specifically, SFG indicated that the hydrogenation of furfural and crotonaldehyde proceed by interfacial hydrogen atom spillover from TiO 2 , while the hydrogenative isomerization of methylcyclopentane (MCP) proceeds by spillover and surface diffusion of cyclohexene over mesoporous zeolites. These studies unequivocally indicated the presence of a particular reaction channel that involved one way flow of charged (i.e. electrons or protons) or neutral species (i.e. reactants) at a broadly defined interface between metals and oxides. In addition to these case studies, experimental approaches employing capillary flow micro-reactors are discussed in relation toward t...

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Study of the L2,3 edges of 3d transition metals by X-ray absorption spectroscopy

Cited by 21 publications

References 28 publications

Modification of the conduction band edge energy via hybridization in quantum dots

Modification of the conduction band edge energy via hybridization in quantum dots

Thickness and angular dependence of the L‐edge X‐ray absorption of nickel thin films

Nanocatalysis II: In Situ Surface Probes of Nano-Catalysts and Correlative Structure–Reactivity Studies

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