Adsorption and reactions at the (010) V2O5 surface: cluster model studies

Witko, Małgorzata; Hermann, Klaus; Tokarz, R.

doi:10.1016/s0920-5861(98)00490-8

Cited by 72 publications

(44 citation statements)

References 39 publications

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“…Among many examples in catalysis, the theoretical investigations on the structural and electronic surface properties and the catalytic reactions of transition-metal oxides, in particular based on vanadium and molybdenum, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] are especially important as they provided a deep insight into the structure-activity relationship of these compounds, used in a variety of applications.…”

Section: Introductionmentioning

confidence: 99%

On the asymmetry in molybdenum–oxygen bonding in the MoO3 structure: ETS–NOCV analysis

Mitoraj

Michalak

2012

Struct Chem

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In the present study, the analysis of natural orbitals for chemical valence (NOCV) combined with the extended-transition-state (ETS) bond-energy decomposition method (ETS-NOCV) was applied to characterize an asymmetry in Mo-O bonding in MoO 3 crystal. Considered were three non-equivalent oxygen sites (O1, O2, O3) in the Mo 7 O 30 H 18 cluster model of (010) surface of MoO 3 . The ETS-NOCV method leads to the conclusion that an increase in the Mo-O distances, from 1.68 Å (for Mo-O1), through 1.73 Å (for Mo-O2), up to 1.94 Å (for Mo-O3), is directly related to decrease in strength of both r-and p-contributions of Mo-O bond. Further, Mo-O connection appeared to exhibit both ionic (the charge transfer from 2p orbital of oxygen to molybdenum) and the covalent (charge accumulation in the region of Mo-O) components. Finally, the trend in the orbital energy stabilization (DE orb ) originating from the dominant r-and p-bond contributions appeared to correlate very well with the oxygen-vacancy formation energies published earlier by Tokarz-Sobieraj et al. (Surf Sci 489:107, 2001).

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Section: Introductionmentioning

confidence: 99%

On the asymmetry in molybdenum–oxygen bonding in the MoO3 structure: ETS–NOCV analysis

Mitoraj

Michalak

2012

Struct Chem

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“…The charge at the V t -type vanadium atom (see Fig. 2a) is smaller than that of vanadium at the saturated surface and equals approximately to ?1.3 (both for V 21 O 65 H 25 and V 14 O 44 H 18 clusters). Its smaller value may be explained by the fact that one of the neighboring oxygen atoms is missing, which causes that the electrons participating in the broken bond still reside on the cation.…”

Section: The V 2 O 5 (010) Surface Clustersmentioning

confidence: 94%

“…2a), respectively. In addition a larger V 21 O 65 H 25 cluster describing both regions simultaneously was considered. The first smaller cluster characterizes the local environment of O(1), O(2) and V centers, whereas the second mimics the surroundings of the O e (2) center.…”

Section: Computational Detailsmentioning

confidence: 99%

“…The first smaller cluster characterizes the local environment of O(1), O(2) and V centers, whereas the second mimics the surroundings of the O e (2) center. In addition cluster V 21 O 65 H 25 allows investigation cluster size convergence.…”

Section: Computational Detailsmentioning

confidence: 99%

“…2a), respectively. In addition, the big V 21 O 65 H 25 cluster, which describes both regions simultaneously, was taken into account to investigate the cluster size convergence. Table 2 summarizes results of the Mulliken population and Mayer bond order analyses for the three above mentioned cluster models.…”

Section: The V 2 O 5 (010) Surface Clustersmentioning

confidence: 99%

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Electronic Structure of Unsaturated V2O5(001) and (100) Surfaces: Ab Initio Density Functional Theory Studies

2009

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Vanadium oxides based materials are well known to play an active role as catalysts in many chemical processes of technological importance like for example hydrocarbon oxidation reactions or selective catalytic reduction of NO x in the presence of ammonia. Usually the (010) surface is pointed out as the most important, however one has to underline that other low-indices surfaces are by far less studied. In the present study the electronic structure of V 2 O 5 (001) and (100) surfaces are determined by ab initio DFT methods using gradient-corrected RPBE exchange-correlation functional. Detailed analyses of the electronic structure of each cluster are performed using charge density distributions, Mayer bond orders, electrostatic potential maps, character of frontier orbitals, and density of states (total as well as partial, atom projected). Results of the calculations show that overall negative charge of the surface oxygen sites scales with their coordination independent of the surface orientation. Terminal oxygen O(1) is charged the least negatively while doubly coordinated atoms -O(2) and O e (2) have charge twice as large. This indicates that bridging (for (001) and (100) netplanes) and edging (only for (001) netplane) oxygen sites are more nucleophilic than terminal vanadyl sites, which becomes important in view of the reactivity of the different sites for surface chemical reactions. Vanadium atoms present at these surfaces are positively charged (electrophilic) and may play a role of electron acceptors. The unsaturated surfaces show a strong tendency to surface relaxation that manifest by large relaxation energies.

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Ab Initio Density Functional Theory Studies of Hydrogen Adsorption at the V2O5(010) Surface

Hermann¹,

Chakrabarti²,

Druzinic³

et al. 1999

phys. stat. sol. (a)

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Adsorption and reactions at the (010) V2O5 surface: cluster model studies

Cited by 72 publications

References 39 publications

On the asymmetry in molybdenum–oxygen bonding in the MoO3 structure: ETS–NOCV analysis

On the asymmetry in molybdenum–oxygen bonding in the MoO3 structure: ETS–NOCV analysis

Electronic Structure of Unsaturated V2O5(001) and (100) Surfaces: Ab Initio Density Functional Theory Studies

Ab Initio Density Functional Theory Studies of Hydrogen Adsorption at the V2O5(010) Surface

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