Ab initio and semiempirical cluster studies on the reactivity of the vanadium pentoxide (010) surface

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

doi:10.1016/s0368-2048(14)80012-1

Cited by 45 publications

(35 citation statements)

References 11 publications

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“…15,16,27,28 Here, the VO 5 pyramids of the ͑010͒ layer are idealized by using averaged interatomic V-O distances d V-O ϭ1.89 Å and O-V-O angles, 86.18°, for all bridging oxygen centers. Further, terminal vanadyl oxygen centers are assumed directly on top of vanadium centers in the direction normal to the ͑010͒ layer with d V-O ϭ1.58 Å.…”

Section: Methodsmentioning

confidence: 99%

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Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

et al. 1999

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Density-functional theory ͑DFT͒ studies are performed to examine geometric and electronic properties of orthorhombic bulk V 2 O 5 as well as of its ͑010͒ oriented surface. Electronic states, total energies, as well as atom forces ͑used to obtain equilibrium geometries͒ are computed with the ab initio full-potential linear augmented plane wave method. The V 2 O 5 (010) surface is modeled by periodic single layers in a repeated slab geometry, which is justified by the weak electronic interlayer coupling found in the bulk calculations. The electronic structure of the V 2 O 5 (010) single-layer slabs, represented by their valence densities of states ͑DOS͒ and its atom contributions, is compared with results of bulk V 2 O 5 and with previous results obtained by DFT surface cluster studies. The comparison yields good qualitative agreement between the different approaches, which confirms the local nature of interatomic binding in V 2 O 5 . Further, the computed valence DOS is used to interpret recent experimental results from photoemission on V 2 O 5 (010), which suggests that differently coordinated oxygen sites at the surface can be identified in the spectrum. Thus, V 2 O 5 (010) photoemission spectra may be used to monitor the participation of oxygen ions in respective surface reactions.

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Section: Methodsmentioning

confidence: 99%

“…Earlier cluster calculations on V 2 O 5 (010) surface properties 15,16,27,28 were based on an idealized bulk geometry, which differs from the presently optimized and experimental structure as described in Sec. II.…”

Section: B Electronic Structurementioning

confidence: 99%

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

et al. 1999

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“…Already some years ago, findings suggested that a metal oxide surface may be envisioned as a collection of clusters (191,192), and subsequent experiments revealed that the identification of the reactive sites in heterogeneous catalysis can be aided by gas-phase studies of neutral and ionic clusters (193), in addition to studies of these materials in solids or solutions. As pointed out by Somorjai (162), surface chemical bonds have cluster-like properties, and in every case where a structure has been determined on a surface, there has been found to be a direct analogy to a comparable organometallic equivalent structure.…”

Section: ϫmentioning

confidence: 99%

Clusters: A bridge across the disciplines of physics and chemistry

Jena

Castleman

2006

Proc. Natl. Acad. Sci. U.S.A.

228

161

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“…The electronic structure of the vanadium pentoxide (010) surface as well as adsorption at this surface have already been examined [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] in different cluster model studies using ab initio Hartree-Fock 3-5 and density functional theory [6][7][8]17 as well as semiempirical INDO (refs [9][10][11][12][13][14] and charge sensitivity analysis 15,16 approaches. Most of these studies have been performed using an idealized V 2 O 5 (010) surface geometry with averaged interatomic V-O distances and O-V-O angles.…”

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confidence: 99%

Surface Cluster Models for V2O5 - Studies of the Importance of Local Geometry

Witko

Tokarz

Hermann

1998

Collect. Czech. Chem. Commun.

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Catalytic properties of the vanadium pentoxide (010) surface are discussed based upon semiempirical quantum chemical calculations using cluster models. Special attention is paid to the role of the second layer in discussing the geometrical factor by using the semiempirical ZINDO approach. Local electronic properties near the different surface oxygen sites are analyzed with the help of Mulliken populations and Meyer bond order indices. Different optimization procedures (with various boundary conditions) are performed for diverse V-O clusters modeling one and two layers. Electronic parameters of the clusters are found to be similar for the cluster in the bulk and optimized geometry. The optimized geometry of the cluster remains much closer to the surface geometry when the optimization is done for the whole cluster, excluding the saturated hydrogen atoms. Optimization of the small fragment of the cluster, results in the significant rearrangement of the cluster structure and leads to the "warped" geometry (bridging oxygen as well as vanadium atoms are shifted out of the surface). Two types of boundary conditions assumed during the optimization process lead to similar results, the optimization of all atoms in the cluster (with saturating hydrogen atoms kept frozen) and the same optimization in the presence of the second layer. The presence of the second layer stabilizes the surface geometry. The role of the second layer is also shown in a formation of an oxygen vacancy at the bridging position.The understanding of catalytic processes occurring on transition metal oxide surfaces requires a detailed knowledge of the physical and chemical properties of the surface, a characterization of the transition complex which is formed at the surface, and a description of the elementary steps of the reaction between the adsorbates. The electronic structure of the surface is responsible for the interaction and binding with an adsorbate, the resulting bond changes, the reaction of adsorbed reactant(s), and the desorption process. Therefore, one has to determine which atoms act as active centers directing the Surface Cluster Models

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Ab initio and semiempirical cluster studies on the reactivity of the vanadium pentoxide (010) surface

Cited by 45 publications

References 11 publications

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Geometric and electronic structure of vanadium pentoxide: A density functional bulk and surface study

Clusters: A bridge across the disciplines of physics and chemistry

Surface Cluster Models for V2O5 - Studies of the Importance of Local Geometry

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