The bonding state of nitrogen segregated on Fe(100) and on iron nitrides Fe4N and Fe2N

Diekmann, W.; Panzner, G.; Grabke, H. J.

doi:10.1016/0039-6028(89)90165-9

Cited by 58 publications

(24 citation statements)

References 33 publications

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“…This is also in agreement with previous observations for N atoms adsorbed on many transition metal single crystal surfaces. 14,[31][32][33] Contrary to previous reports, 33 the peak at 397.7 eV cannot be assigned to adsorbed NO, since no O was detected in our case by either XPS or Auger. The assignment of the shoulder to surface N would also explain that the absolute area of the shoulder does not decrease with the film thickness.…”

Section: B Photoemission (X-ray Core Level Photoelectron Spectroscopcontrasting

confidence: 52%

Intrinsic surface band bending inCu3N(100)ultrathin films

et al. 2007

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Highly homogeneous, ultrathin films of copper nitride ͑Cu 3 N͒ have been grown on Fe͑001͒ at room temperature using a Cu evaporator and a radio-frequency plasma source to obtain atomic nitrogen in a UHV environment. Cu 3 N is a semiconductor with the valence band edge at −0.65± 0.05 eV below the Fermi Level. The formation of copper nitride can be detected spectroscopically by the shape of the Cu LVV-Auger electron transition, which changes sensibly in shape and position compared to metallic Cu. Cu 3 N grows epitaxially with the substrate forming flat disklike mosaic blocks, ͑001͒ oriented. Both x-ray core level photoelectron spectroscopy and ultraviolet photoelectron spectroscopy photoemission experiments have been used to study the electronic structure. A first-principles calculation has been performed and compared with the measured spectra.

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Section: B Photoemission (X-ray Core Level Photoelectron Spectroscopcontrasting

confidence: 52%

Intrinsic surface band bending inCu3N(100)ultrathin films

et al. 2007

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“…Each of the latter shows a similar marked trend as a function of R, that is, a marked drop in the intensity in the low N1s energy region of the spectra (396 eV-398 eV) when R decreases. The literature indicates that this low energy region corresponds to iron nitrides or nitrided iron surfaces [26][27][28][29]. For each material collection, the spectra recorded for low R are quite similar.…”

Section: As-prepared Materialsmentioning

confidence: 59%

Synthesis and Characterization of Carbon/Nitrogen/Iron Based Nanoparticles by Laser Pyrolysis as Non-Noble Metal Electrocatalysts for Oxygen Reduction

Pérez

Jorda

Bonville

et al. 2018

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This paper reports original results on the synthesis of Carbon/Nitrogen/Iron-based Oxygen Reduction Reaction (ORR) electrocatalysts by CO 2 laser pyrolysis. Precursors consisted of two different liquid mixtures containing FeOOH nanoparticles or iron III acetylacetonate as iron precursors, being fed to the reactor as an aerosol of liquid droplets. Carbon and nitrogen were brought by pyridine or a mixture of pyridine and ethanol depending on the iron precursor involved. The use of ammonia as laser energy transfer agent also provided a potential nitrogen source. For each liquid precursor mixture, several syntheses were conducted through the step-by-step modification of NH 3 flow volume fraction, so-called R parameter. We found that various feature such as the synthesis production yield or the nanomaterial iron and carbon content, showed identical trends as a function of R for each liquid precursor mixture. The obtained nanomaterials consisted in composite nanostructures in which iron based nanoparticles are, to varying degrees, encapsulated by a presumably nitrogen doped carbon shell. Combining X-ray diffraction and Mossbauer spectroscopy with acid leaching treatment and extensive XPS surface analysis allowed the difficult question of the nature of the formed iron phases to be addressed. Besides metal and carbide iron phases, data suggest the formation of iron nitride phase at high R values. Interestingly, electrochemical measurements reveal that the higher R the higher the onset potential for the ORR, what suggests the need of iron-nitride phase existence for the formation of active sites towards the ORR.

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“…24 The 2p states of the adsorbed N atoms appear in the spectrum recorded with He I ͑21.2 eV͒ photons as an intense peak at 5 eV below the Fermi level. 25 The adsorption geometry, charge transfer, and energy positions of both the N 2p level and the d states of Fe are reproduced by our first-principles calculations. Notice that the N 2p level at 5 eV recorded with He I photons is identical to the one observed in ␥Ј-Fe 4 N͑100͒, but, contrary to ␥Ј-Fe 4 N, the UPS spectrum measured with He II ͑40.8 eV͒ photons shows only a barely detectable N 2p structure around −5 eV.…”

Section: B Electronic Structure Of ␥ј-Fe 4 N"100…mentioning

confidence: 77%

Electronic structure of ultrathinγ′−Fe4N(100) films epitaxially grown on Cu(100)

et al. 2007

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The electronic structure of ultrathin films of ␥Ј-Fe 4 N͑100͒ deposited on Cu͑100͒ has been characterized by a combination of photoelectron spectroscopies, scanning tunneling microscopy, and diffraction techniques. The comparison of the data with first-principles simulations sheds light on magnetic moments, type of bonding, and charge transfer. N atoms residing in the bulk or at the surface are found to be distinguishable. The ␥Ј-Fe 4 N͑100͒ surface is laterally heterogeneous and contains both areas reconstructed with a p4gm͑2 ϫ 2͒ symmetry and bulklike terminated. The densities of states of the reconstructed and unreconstructed areas of the surface are obtained and compared with the experiment. Comparison with c͑2 ϫ 2͒N/Fe͑100͒ provides spectroscopic evidence that a subsurface excess of N drives the p4gm͑2 ϫ 2͒ reconstruction.

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The bonding state of nitrogen segregated on Fe(100) and on iron nitrides Fe4N and Fe2N

Cited by 58 publications

References 33 publications

Intrinsic surface band bending inCu3N(100)ultrathin films

Intrinsic surface band bending inCu3N(100)ultrathin films

Synthesis and Characterization of Carbon/Nitrogen/Iron Based Nanoparticles by Laser Pyrolysis as Non-Noble Metal Electrocatalysts for Oxygen Reduction

Electronic structure of ultrathinγ′−Fe4N(100) films epitaxially grown on Cu(100)

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