The reaction of gas-phase oxidation of 4-methylpyridine on individual V2O5, binary and ternary vanadium-oxide catalysts was studied. These catalysts were modified by additives of SnO2 and TiO2. It was found that modifying V2O5 leads to increase the activity of binary contacts. Upon transition from binary V2O5<...

The energy landscape of the fast-ion conductor Bi 4 V 2 O 11 is studied using density functional theory. There are a large number minima, dominated by low-lying thermally accessible configurations in which there equal numbers oxygen vacancies each vanadium–oxygen layer, range vanadium coordinations and variation Bi–O V–O distances. By dividing local minima into sets configurations, we then exam...

Vanadiumoxid Monoschichtkatalysatoren. I. Darstellung, Charakterisierung und thermische Stabilitiit Inha l t s i ibers ich t . Durch Chemisorption von Vana,dat(V)-Anionen aus waBrigen Losungen, bzw. Cheniisorption von gasformigem V,O,(OH), warden Va.nadinoxidkatalysatoren des Monoschichttyps dargestellt. Mit A1,0,, Cr,O,, TiO,, CeO, nnd ZrOz als Trageroxiden, konnen Katalysatoren mit, einer ung...

The very sensitive, fairly selective direct spectrophotometric method for the determination of trace amount of vanadium (V) with naphthalene -1, 5 -diamine has been developed. Naphthalene -1, 5 -diamine reacts in slightly acidic (0.0001– 0.001 M H2SO4 or pH 4.0–5.5) alcohol media with vanadium (V) to give a red–violet chelate which has an absorption maximum at 531 nm. The stoichiometric composi...

M2O3–TiO2 (M = Ga, In and La) composite oxides were prepared by a co-precipitation method with in situ generated ammonium hydroxide and were impregnated with 12 wt.% V2O5. The M2O3-TiO2 and V2O5/M2O3-TiO2 (M = Ga, In and La) samples were subjected to thermal treatments from 773 to 1073 K and were investigated by X-ray diffraction, FT-infrared, and BET surface area methods to establish the effec...

A new potassium vanadium arsenate, tripotassium trivanadium bis-(arsenate) hexa-oxide, K(3)VO(2)(V(2)As(2)O(12)), was synthesized by a solid-state reaction at 743 K. The structure is built up from VO(5) pyramids, VO(4) tetra-hedra (.m. symmetry) and AsO(4) tetra-hedra linked together by corner-sharing to form a three-dimensional framework. The two crystallographically independent K(+) cations, ...

The effect of the irradiation with Al Ka X-rays during an XPS measurement upon the surface vanadium oxidation state of a fresh in vacuum cleaved V2O5(001) crystal was examined. Afterwards, the surface reduction of the V2O5(001) surface under Ar + bombardment was studied. The degree of reduction of the vanadium oxide was determined by means of a combined analysis of the O1s and V2p photoelectron...

Neutral vanadium, niobium, and tantalum oxide clusters are studied by single photon ionization employing a 26.5 eV/photon soft x-ray laser. During the ionization process the metal oxide clusters are almost free of fragmentation. The most stable neutral clusters of vanadium, niobium, and tantalum oxides are of the general form (MO2)0,1(M2O5)y. M2O5 is identified as a basic building unit for thes...

About 90 years ago, Henze discovered high levels of vanadium in the blood (coelomic) cells of an ascidian collected from the Bay of Naples. His discovery attracted the interdisciplinary attention of chemists, physiologists, and biochemists. Two decades ago, we quantified the vanadium levels in several ascidian tissues definitively using neutron-activation analysis and revealed that some species...

V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if ...