The defined adsorption site of sodium on the TiO2(110)–(1×1) surface

Lagarde, P.; Flank, A.‐M.; Prado, Rogério Junqueira; Bourgeois, S.; Jupille, Jacques

doi:10.1016/j.susc.2004.01.054

Cited by 17 publications

(12 citation statements)

References 27 publications

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“…Our finding of only partial ionization of the surface-adsorbed K species above ¾0.25 ML is at variance with the finding (based on EXAFS studies) that Na is nearly fully ionized at submonolayer coverages on TiO 2 110 . 20 As discussed in detail in Ref. 13, the emission from bare titania is due to the resonance ionization-Auger neutralization process sequence whereby the He Ł probe atom is first resonantly ionized; its re-neutralization involves two O 2p electrons, one of which is emitted.…”

Section: The Mies Resultsmentioning

confidence: 99%

MIES and UPS(HeI) studies on reduced TiO₂(110)

Krischok

Günster

Goodman

et al. 2005

Surf. Interface Anal.

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We have studied reduced TiO 2 (110) surfaces by combining metastable impact electron spectroscopy (MIES) and UPS(HeI). The reduced Ti species were preparation-induced: their number density was modified either by adsorption of K atoms or by a combined annealing/oxygen exposure procedure. The emission from the bandgap state (binding energy 0.9 eV), caused by reduced Ti 3+ 3d species, was monitored. Bandgap emission is seen clearly with UPS(HeI) and thus can be used to monitor the number density of the nearsurface reduced species. A corresponding spectral structure cannot be seen with MIES. We propose that the excess charge density introduced either by preparation-induced oxygen vacancies or by K adsorption is delocalized over several surface and subsurface Ti sites; this, together with the partial shielding of the reduced Ti species, prevents detection of the reduced Ti species with MIES.The re-oxidation and restructuring of the reduced TiO 2 (110) surface, caused by simultaneous oxygen exposure and annealing, was studied at temperatures between 400 and 770 K, again by recording the Ti 3+ 3d emission (0.9 eV bandgap state) with UPS(HeI). The surface can be completely re-oxidized by oxygen exposure at any selected annealing temperature in the range given above. Morphology changes, leading to a partially reduced surface, take place when the re-oxidized surface is further annealed at T > 600 K under reducing conditions. The results give support to the assumption that the re-oxidation is caused by the growth of additional titania whereby the Ti stems from the bulk and the oxygen originates from the gas. The restructuring of the re-oxidized surface upon annealing under reducing conditions appears to be due to diffusion of Ti interstitials to the surface.

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Section: The Mies Resultsmentioning

confidence: 99%

MIES and UPS(HeI) studies on reduced TiO₂(110)

Krischok

Günster

Goodman

et al. 2005

Surf. Interface Anal.

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“…Lagarde et al [273] applied extended X-ray absorption fine structure (EXAFS) to determine the adsorption site of Na. They, however, found that for Na coverage ranging between 0.25 and 0.5 ML the metal is "between" a three-fold coordinated site where it is bonded to two bridging O atoms and one in-plane O atom.…”

Section: Tio 2 Surfacesmentioning

confidence: 99%

Interaction of nanostructured metal overlayers with oxide surfaces

Wagner

2007

Surface Science Reports

722

651

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“…Table 1), in favor of the hollow site for larger atoms (Ca-V) and in favor of bridging site for smaller ones (Fe-Cu). In the cases of Ni and Cu, the bridge site is the only stable position; optimization starting from h led to b. h site was proposed for the alkali metals [54,55]. The h site was also recently found as the preferred adsorption site in the cases of V and Fe [19,23].…”

Section: Computational Detailsmentioning

confidence: 99%

First-row transition metal atoms adsorption on rutile TiO2(110) surface

et al. 2012

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We performed periodic DFT calculations for adsorption of metal atoms on a perfect rutile TiO 2 (110) surface (at low coverage, h = 1/3) to investigate the interaction of an individual metal atom with TiO 2 and to compare it with a study previously done on MgO(100). We considered partial period of Mendeleev's table from K to Zn. The overall evolution of the adsorption energies shows two maxima as for MgO (100). Two main differences, however, exist: the adsorption energy is much stronger and the first maximum is enhanced relative to the second one. This is attributed to the reducibility of the surface titanium cation. When the adsorbed metal is electropositive, it is oxidized under adsorption transferring electrons to titanium cations. We present the effect of introducing a Hubbard term to the gradient-corrected approximation band-structure Hamiltonian (GGA ? U). The introduction of a reasonable Hubbard correction preserves the trends and allows localizing the electron of the reduction on Ti atoms in the near surface region. Finally, our results conclude that for heavier M atoms of the period, insertion is energetically favored relative to adsorption.

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The defined adsorption site of sodium on the TiO2(110)–(1×1) surface

Cited by 17 publications

References 27 publications

MIES and UPS(HeI) studies on reduced TiO₂(110)

MIES and UPS(HeI) studies on reduced TiO₂(110)

Interaction of nanostructured metal overlayers with oxide surfaces

First-row transition metal atoms adsorption on rutile TiO2(110) surface

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The defined adsorption site of sodium on the TiO2(110)–(1×1) surface

Cited by 17 publications

References 27 publications

MIES and UPS(HeI) studies on reduced TiO2(110)

MIES and UPS(HeI) studies on reduced TiO2(110)

Interaction of nanostructured metal overlayers with oxide surfaces

First-row transition metal atoms adsorption on rutile TiO2(110) surface

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Product

Resources

About

MIES and UPS(HeI) studies on reduced TiO₂(110)

MIES and UPS(HeI) studies on reduced TiO₂(110)