We use density functional theory to examine structure− activity relationships of small vanadia clusters supported on anatase TiO2(001) and rutile TiO2(110) surfaces. A thermodynamic analysis indicates that the vanadia monomer cluster can be stabilized on the anatase TiO2(001) surface in a catalytically relevant oxygen environment. On the other hand, vanadia clusters tend to aggregate into dimer...

The oxidative dehydrogenation (ODH) of propane was investigated on vanadia dispersed on alumina containing a nominal polymolybdate monolayer (4.8 Mo/nm2). Dehydrogenation rates and selectivities on these catalysts were compared with those on vanadia domains dispersed on alumina. At a given vanadia surface density, ODH reaction rates per gram of catalyst were about 1.5–2 times greater on MoOx -c...

With regard to the application in a microstructured reactor, a special VOx/Al2O3 catalyst powder (3 μm) was prepared and characterised by BET, XRD, UV/Vis DRS, and Raman spectroscopy. The higher the vanadium content, the higher the degree of polymerisation of the vanadium species on the support surface and the lower the BET surface area. Pelletised powders were tested in conventional tubular re...

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...

The catalytic properties of Al2O3-supported vanadia with a wide range of VOx surface density (1.4-34.2 V/nm) and structure were examined for the oxidative dehydrogenation of ethane and propane. UV-visible and Raman spectra showed that vanadia is dispersed predominately as isolated monovanadate species below ~2.3 V/nm. As surface densities increase, two-dimensional polyvanadates appear (2.3-7.0 ...

The activity and selectivity of aluminaand magnesia-supported vanadia for propane oxidative dehydrogenation can be enhanced by can be enhanced by interactions of vanadia with molydena for the alumina-supported catalyst and by phosphorous doping for the magnesia-supported catalyst.

The information obtained from the characterization of vanadium oxide single crystal surfaces is related to the study of vanadia nanoparticles supported on silica and alumina thin films, model systems for the so-called ‘‘supported monolayer vanadia catalysts’’. It is found that these particles have properties similar to V2O3 surfaces, where the topmost V ions are involved in vanadyl groups and h...

Supported vanadium oxide catalysts contain a vanadium oxide phase deposited on a high surface area oxide support (e.g., Al2O3, SiO2, TiO2, etc.) and have found extensive applications as oxidation catalysts in the chemical, petroleum and environmental industries. This review of supported vanadium oxide catalysts focuses on the fundamental aspects of this novel class of catalytic materials (molec...

Formation of vanadia species during the calcination of ball milled mixture of V2O5 with TiO2 was studied by Raman spectroscopy in situ and at ambient conditions. It is found that calcination in air leads to fast (1–3 h) spreading of vanadia over TiO2 followed by a slower process leading to the formation of a monolayer vanadia. The calcinated catalyst showed higher activity during toluene oxidat...

The performance of synergetic hybrid aerogel materials of vanadia and graphene as electrode materials in supercapacitors was evaluated. The hybrid materials were synthesized by two methods. In Method I, premade graphene oxide (GO) hydrogel was first chemically reduced by L-ascorbic acid and then soaked in vanadium triisopropoxide solution to obtain V2O5 gel in the pores of the reduced graphene ...