Resonant photoemission spectroscopy study of electronic structure of V2O5

Wu, Qi‐Hui; Thißen, Andreas; Jaegermann, Wolfram; Schüz, M.; Schmidt, Peter

doi:10.1016/j.cplett.2006.08.071

Cited by 26 publications

(15 citation statements)

References 27 publications

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“…This is in line with a recent experimental study, 57 where the electronic structure of V 2 O 5 has been probed by resonant photoemission spectroscopy (RPES). RPES results showed that the approximate charge on the V ion and the O ion in V 2 O 5 is +3 and -1.2, respectively, indicating that the simple ionic model of bonding is not valid for such a system.…”

Section: Resultssupporting

confidence: 73%

Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

et al. 2010

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The effect of (001) TiO 2 anatase support on the electronic and catalytic properties of a V 2 O 5 monolayer is analyzed using density functional theory (DFT). The catalyst is represented by both clusters and periodic slabs. Using two experimentally relevant models of monolayer V 2 O 5 /TiO 2 (anatase) catalyst, both weak and strong interactions between a V 2 O 5 monolayer and the TiO 2 support have been investigated. In the first model, where a crystallographic (001) V 2 O 5 layer is placed on top of the (001) TiO 2 support, the weak interaction between vanadia and titania does not result in a major reconstruction of the active phase. Nevertheless, the changes in the electronic properties of the system are evident. The deposition of the vanadia monolayer on the titania substrate results in charge redistribution, enhancing the Lewis acidity of vanadium and the chemical hardness above the vanadyl oxygen, and in a shift of the Fermi level to lower binding energies accompanied by a reduction in the band gap. In the second model, where the (001) titania anatase structure is extended with a VO 2 film terminated by half a monolayer of vanadyl oxygen, apart from a similar electronic effect, the strong interaction of the vanadia phase with the titania support resulting from a high order of epitaxy has an important effect on the structure of the active phase. Atomic hydrogen adsorption is most favorable on the vanadyl oxygen of all the investigated surfaces, while the adsorption energy on this site increases by ∼10 kJ/mol due to the weak interaction between vanadia and titania and is further increased by ∼50 kJ/mol as a stronger interaction between the two phases is achieved, all in agreement with the increase in the negative electrostatic potential above the vanadyl site. The observed trends in the reactivity of the oxygen sites in H adsorption for the different catalyst models are successfully explained in terms of a frontier orbital analysis. IntroductionTransition metal oxides are widely used as catalysts for the oxidation of hydrocarbons. Especially vanadium oxide based catalysts are among the most active for the oxidation of both aliphatic and aromatic hydrocarbons. An important example of such a catalyst is V 2 O 5 /TiO 2 (anatase), which is used in industry as an effective catalyst for the production of phthalic anhydride from o-xylene.1,2 For the anatase support, although the (101) surface is thermodynamically more stable, the (100) and (001) faces are found in the industrial TiO 2 powders.3 Earlier experimental studies indicate that this catalytic system is of high performance when it consists of a monolayer of V 2 O 5 upon a TiO 2 (anatase) substrate, showing activity and selectivity not observed in the unsupported V 2 O 5 or TiO 2 anatase.2,4 The enhanced catalytic performance can be attributed to a synergetic effect between the active phase and the support. In order to unravel the role of the TiO 2 support on a V 2 O 5 monolayer catalyst, ab initio methods can help to provide a better understanding of the rel...

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Section: Resultssupporting

confidence: 73%

Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

et al. 2010

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“…The BEs are determined as 530.2 and 531.5 eV, respectively. According to their binding energies, the O1 line is assigned to O 2− ions, while the broad shoulder peak is probably ascribed to water and hydroxide . Usually, oxygen species have stronger electron negativities than C atoms; the electrons are most likely to transfer from graphene to oxygen species, indicating that p‐type doping is induced on the graphene lattice, which causes the red‐shift of 2D Raman band.…”

Section: Resultsmentioning

confidence: 99%

Influence of ambient conditions on the electronic structure of graphene/copper interface

Huang

Ren

et al. 2015

Surface & Interface Analysis

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Graphene films grown on the copper foils using chemical vapor deposition have been emphasized in the previous scientific studies and technical applications because of the high quality/cost ratio. However, no enough attention has been paid to the fundamentally important issue on the stability of graphene/copper interface compared with quality of the grown graphene films, though the properties of graphene/metal interface largely affect the Ohmic contacts in graphene-based electronics (e.g. highfrequency graphene transistors). Here, we investigated the electronic structure of graphene/copper interface which has been stored in the ambient conditions for different periods. Raman and photoelectron spectroscopic data indicated that the oxygen species do not prefer to adsorb on the graphene surface but insert into the graphene/copper interface. This results in the p-doping of graphene, formation of the surface positive dipole, and energy upshift of the graphene's Dirac point.

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“…Theoretical calculations might solve these problems, but so far little theoretical work has been reported on this topic, [16,17] although the theoretical investigations on the electronic structure of V 2 O 5 are numerous. [14,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] Previous experimental studies have reported that as a result of the intercalation of Li, the electronic structure and optical properties of V 2 O 5 will change. [11,33] For example, a reduction of V ions and a shift of the Fermi level as well as a blue shift of the ultraviolet (UV) absorption of Li x V 2 O 5 occur with an increase of Li.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structures of Li_xV₂O₅ (x=0.5 and 1): A Theoretical Study

2008

ChemPhysChem

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The electronic properties of alpha-Li(x)V2O5 (x=0.5 and 1) are investigated using first principle calculations based on density functional theory with local density approximation. Different intercalation sites for Li in the V2O5 lattices are considered, showing different influences on the electronic structures of Li(x)V2O5. The lowest total energy is found when Li is only intercalated along the c axis between two bridging oxygen ions of sequential V2O5 layers. The intercalation of Li into V2O5 does not change the electron transition property of V2O5, which is an indirect band gap semiconductor, but leads to a reduction of vanadium ions and an increase of the Fermi level of Li(x)V2O5 arising from the electron transfer from the Li 2 s orbital to the initially empty conduction band of the V2O5 host.

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Resonant photoemission spectroscopy study of electronic structure of V2O5

Cited by 26 publications

References 27 publications

Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

Influence of ambient conditions on the electronic structure of graphene/copper interface

Electronic Structures of Li_xV₂O₅ (x=0.5 and 1): A Theoretical Study

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Resonant photoemission spectroscopy study of electronic structure of V2O5

Cited by 26 publications

References 27 publications

Theoretical Study of the Effect of (001) TiO2Anatase Support on V2O5

Theoretical Study of the Effect of (001) TiO2Anatase Support on V2O5

Influence of ambient conditions on the electronic structure of graphene/copper interface

Electronic Structures of LixV2O5 (x=0.5 and 1): A Theoretical Study

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Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

Theoretical Study of the Effect of (001) TiO₂Anatase Support on V₂O₅

Electronic Structures of Li_xV₂O₅ (x=0.5 and 1): A Theoretical Study