an isolate from polluted soil identified as aspergillus sp. ms-100 was able to consume vanadium oxide octaethyl porphyrin as a model for protoporphyrins in crude oil. the isolate degrades about 55% of vanadium oxide octaethyl porphyrin (vooep) under optimum conditions during 7 days. the release of more than 0.96 mgl-1 of free vanadium into the aqueous phase was confirmed using atomic absorption...

The present research investigated the sol–gel preparation, dielectric and ferroelectric properties of PZT films doped with 5 mol% vanadium oxide. Stable PZTV sols can be readily formed, and homogeneous, micrometer thick and pinhole-free PZTV films were obtained by using spin coating followed with rapid annealing. The X-ray diffraction patterns revealed that no parasitic or secondary phases were...

the effects of confinement in carbon nanotubes on fischer-tropsch (ft) activity, selectivity and lifetime of carbon nanotubes (cnts) supported iron catalysts are reported. a method was developed to control the position of the catalytic sites on either inner or outer surface of carbon nanotubes. tem analyses revealed that more than 80% of iron oxide particles can be controlled to be positioned a...

Raman, UV-Vis and X-ray photoelectron spectroscopy were combined in one experimental setup to directly study the interplay between structure and dispersion of SBA-15 supported vanadium oxide during dehydration. The fully hydrated catalyst is slightly reduced but consists mainly of V species with pseudo-octahedral V coordination strongly resembling the xerogel V2O5·1.2H2O. After dehydration a hi...

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...

Vanadium phosphorous oxide (VPO) is traditionally manufactured from solid vanadium oxides by synthesizing VOHPO4·0.5H2O (the precursor) followed by in situ activation to produce (VO)2P2O7 (the active phase). This paper discusses an alternative synthesis method based on sol-gel techniques. Vanadium (V) triisopropoxide oxide was reacted with ortho-phosphoric acid in an aprotic solvent. The produc...

Vanadium dioxide (VO(2)) undergoes a sharp metal-insulator transition (MIT) in the vicinity of room temperature and there is great interest in exploiting this effect in novel electronic and photonic devices. We have measured the work function of vanadium dioxide thin films across the phase transition using variable temperature Kelvin force microscopy (KFM). The work function is estimated to be ...

A quadrupole-based mass spectrometer equipped with an electrospray ionization source was used to examine the gas-phase reactivity of various vanadium-oxide cations which mediate the oxidative dehydrogenation (ODH) of small alkenes and alkanes. For ion generation, a solution of V6O7(OMe)12 dissolved in deuterated methanol was subjected electrospray under very harsh conditions to obtain smaller v...

new forms of vanadium oxide nanoporous were fabricated using a simple chemical synthesis method. vanadium pentoxide (v2o5) nanoporous were synthesized by sodium metavanadate as precursor and ethylene glycol as surfactant. the samples were characterized by high resolution transmission electron microscopy (hrtem), field effect scanning electron microscopy (fesem) and x-ray diffraction (xrd), four...

Vanadium-niobium oxide catalysts containing variable amounts of vanadium and prepared by coprecipitation were investigated using 51V solid-state NMR. It was found that, in samples containing less than about 8 mol % V2O5, vanadium occurs in three different oxygen environments: in isolated tetrahedra, in comer-sharing tetrahedra (pyrovanadate), and in distorted octahedra. The number of octahedral...