Preface

Grzybowska-S̈wierkosz, B.; Trifirò, Ferruccio

doi:10.1016/s0926-860x(97)80165-2

Cited by 52 publications

(30 citation statements)

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“…This diversity makes vanadium oxides technologically relevant and leads to various applications, such as in light detectors, write-erase media, electrical and optical switching devices, as well as in heterogeneous catalysis. 1,2 From the chemical point of view, the versatility of vanadium oxides is based on the large number of possible vanadium oxidation states ranging from V 2+ to V 5+ ͑VO, V 2 O 3 , VO 2 , and V 2 O 5 ͒ as well as on the different oxygen coordination geometries occurring in the crystal structures. From a physical point of view, vanadia has attracted a lot of interest because of its rich electronic and magnetic structure and its phase transitions, in particular, the metal-insulator transition triggered by changes in temperature, doping level, and external pressure exerted on the oxide material.…”

Section: Introductionmentioning

confidence: 99%

Local band gap modulations in non-stoichiometricV2O3films probed by scanning tunneling spectroscopy

et al. 2008

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Scanning tunneling microscopy and spectroscopy have been used to investigate the electronic structure of non-stoichiometric V 2 O 3 islands with a vanadyl termination grown on Au͑111͒. The spectroscopic measurements reveal the correlation gap of bulk V 2 O 3 that varies between 0.2 and 0.75 eV for different sample preparations. In addition, gap modulations of roughly 0.2 eV are observed at different locations within the oxide islands. The changes in gap size are attributed to local deviations from the ideal V 2 O 3 stoichiometry in films produced at more oxidizing or reducing conditions. By evaluating the position of the Fermi level with respect to the band edges, a p-type conductance characteristic is dominantly observed for the V 2 O 3 islands, indicative of an efficient hole doping of the V 3d band.

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Section: Introductionmentioning

confidence: 99%

Local band gap modulations in non-stoichiometricV2O3films probed by scanning tunneling spectroscopy

et al. 2008

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“…The bond order (1.95) for V=O(1) bonds indicate their double nature, while the V-O(2)-V bridges (bond orders of 0.83 and 0.83) are described by single bonds, with a greater ionic contribution that for V=O (1). Both, populations and bond orders do not yield noticeable differences between the (001) and (100) oriented surfaces.…”

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

confidence: 94%

“…Vanadium oxide based catalysts are of a great importance in many technological processes like the oxidation of SO 2 to SO 3 , naphthalene or o-xylene to phthalic anhydride or nbutane to maleic anhydride, or the ammoxidation of propane to acrylonitrile [1][2][3][4][5]. The enormous chemical interest in vanadia and vanadia-based systems comes from their use as catalyst components, in particular in selective hydrocarbon oxidation reactions where oxygen from different surface sites participates in the reaction.…”

Section: Introductionmentioning

confidence: 99%

“…The enormous chemical interest in vanadia and vanadia-based systems comes from their use as catalyst components, in particular in selective hydrocarbon oxidation reactions where oxygen from different surface sites participates in the reaction. Vanadia-based catalysts can be also applied in the protection of the natural environment i.e., in the selective catalytic reduction (SCR) of NO x in the presence of ammonia [1,6,7]. Catalytic properties of vanadia may be connected with the fact that this material can expose different types of surfaces, those build of saturated vanadium (like the single crystal (010) surface) and those coordinatively unsaturated where surface ions accumulate excess charge and generate significant variations in the surface potential [8] (e.g., at (100) and (001) surfaces).…”

Section: Introductionmentioning

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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“…Among these, vanadium oxides represent an important class of systems which are widely studied and used in many technological applications [4,5]. In particular, vanadia (V 2 O 5 ) based compounds form important catalysts for hydrocarbon oxidation.…”

Section: Introductionmentioning

confidence: 99%

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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Preface

Cited by 52 publications

References 0 publications

Local band gap modulations in non-stoichiometricV2O3films probed by scanning tunneling spectroscopy

Local band gap modulations in non-stoichiometricV2O3films probed by scanning tunneling spectroscopy

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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