X-ray photoelectron emission from iron metal

Höchst, H.; Goldmann, A.; Hüfner, S.

doi:10.1007/bf01360893

Cited by 33 publications

(8 citation statements)

References 21 publications

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“…No deviation between the two calibration methods was found (within the error of the measurement). We therefore believe that the deviation is due to an upward shift of the theoretical DOS, as previously reported in the case of Fe . The various parameters used to adjust the theoretical DOS are outlined in Table S1 of the Supporting Information.…”

Section: Resultsmentioning

confidence: 55%

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

et al. 2012

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The valence band structures (VBS) of eight transition metals (Fe, Co, Ni, Cu, Pd, Ag, Pt, Au) were investigated by photoelectron spectroscopy (PES) using He I, He II, and monochromatized Al Kα excitation. The influence of final states, photoionization cross-section, and adsorption of residual gas molecules in an ultrahigh vacuum environment are discussed in terms of their impact on the VBS. We find that VBSs recorded with monochromatized Al Kα radiation are most closely comparable to the ground state density of states (DOS) derived from quantum mechanics calculations. We use the Al Kα-excited PES measurements to correct the energy scale of the calculated ground-state DOS to approximate the "true" ground-state d-band structure. Finally, we use this data to test the d-band center model commonly used to predict the electronicproperty/catalytic-activity relationship of metals. We find that a simple continuous dependence of activity on d-band center position is not supported by our results (both experimentally and computationally).

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Section: Resultsmentioning

confidence: 55%

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

et al. 2012

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“…On the other hand, the TPR profiles of the fresh catalysts confirms the presence of only one oxidized species (Fe3O4, [53]) that can be reduced at around 600 ⁰C (see figure S4). Analysis of the surface of the different catalysts after 50 h on stream by X-ray photoelectron spectroscopy (XPS) at the Fe2p level reveals in most cases the following contributions: a first peak of the spectra at 706.9 eV corresponding to metallic iron [54], a second peak at 707.9 eV characteristic of iron carbides [55], two subsequent peaks at 710.6 and 712.6 eV corresponding to Fe(II) and Fe(III) 2p3/2 respectively, a group of satellite peaks around 719 eV, two additional peaks at 723.9 and 725.6 eV arising from Fe(II) and Fe (III) 2p1/2 [25,56] and, finally, the Fe 2p1/2 shake-up around 733.4 eV(see figure 3.b). To address the evolution of iron species, additional XPS measurements at the Fe2p level were carried out in the fresh Fe/C+K sample (see figure S5).…”

Section: Resultsmentioning

confidence: 99%

Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO₂ to Short Chain Olefins

et al. 2018

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We report the synthesis of a highly active, selective and stable catalyst for the hydrogenation of CO2 to short chain olefins in one single step by using a Metal Organic Framework as catalyst precursor. By studying the promotion of the resulting Fe(41 wt %)-carbon composites with different elements (Cu, Mo, Li, Na, K, Mg, Ca, Zn, Ni, Co, Mn, Fe, Pt and Rh) we have found that only K is able to enhance olefin selectivity. Further catalyst optimization in terms of promoter loading results in catalysts displaying unprecedented C2-C4 olefin space time yields: 33.6 mmol·gcat -1 ·h -1 at XCO2 = 40%, 320 ⁰ C, 30 bar, H2/CO2 = 3, and 24000 mL·g -1 ·h -1 . Extensive characterization demonstrates that K promotion affects catalytic performance by: (i) promoting a good balance between the different Fe active phases playing a role in CO2 hydrogenation, namely 2 iron oxide and iron carbides and by (ii) increasing CO2 and CO uptake while decreasing H2 affinity, interactions responsible for boosting olefin selectivity.

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“…In a similar fashion, another two peaks, labeled c and d, representing photoelectron emission arising from Fe 3d and Fe 4s valence electrons, are required to deconvolute the Fe valence band peaks, as shown in the upper plot of Figure ; these are the principal components contributing to the spectrum and have been variously attributed. The relative Fe:C intensity ratios in the valence band spectra are presented in Figure ; this ratio is independent of deposition rate, which agrees well with the behavior of the core level spectra shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

The Effect of Deposition Rate on the Morphology of Fe Nanoparticles on Highly Oriented Pyrolytic Graphite, As Studied by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy

2011

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The effect of deposition rate on the morphology of Fe nanoparticles (NPs) on highly oriented pyrolytic graphite (HOPG) surfaces has been studied by atomic force microscopy (AFM) and in situ X-ray photoelectron spectroscopy (XPS). AFM provided the NP dimensions and the extent of surface coverage, while XPS (both core and valence levels) indicated the interaction of Fe NPs with the HOPG substrate and showed the evolutions of binding energies, full widths at half-maxima, and component peak intensity ratios, all as a function of deposition rate. The results indicate that Fe NPs react with both substrate and residual gases in the high vacuum of the instrument, forming carbide and oxide surface contaminant layers around the NPs. The NP dimensions are essentially independent of deposition rate and of the amount deposited, but the NP surface coverage is inversely related to the deposition rate, with a higher rate resulting in a lower surface coverage. Combining the NP surface coverage and the XPS peak intensity ratios, we find a relationship between deposition rate and surface contaminant layer thickness.

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X-ray photoelectron emission from iron metal

Cited by 33 publications

References 21 publications

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO₂ to Short Chain Olefins

The Effect of Deposition Rate on the Morphology of Fe Nanoparticles on Highly Oriented Pyrolytic Graphite, As Studied by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy

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X-ray photoelectron emission from iron metal

Cited by 33 publications

References 21 publications

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

Using Photoelectron Spectroscopy and Quantum Mechanics to Determine d-Band Energies of Metals for Catalytic Applications

Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO2 to Short Chain Olefins

The Effect of Deposition Rate on the Morphology of Fe Nanoparticles on Highly Oriented Pyrolytic Graphite, As Studied by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy

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Metal Organic Framework-Derived Iron Catalysts for the Direct Hydrogenation of CO₂ to Short Chain Olefins