نتایج جستجو برای: Vanadium oxide catalysts

تعداد نتایج: 211797  

Abdollah Fallah Shojaei, Alimorad Rashidi, Mina Ghias Robabeh Mousavi

In this study at first, in laboratory, three types of vanadium oxide were produced by using porous graphene and amine framework in hydrothermal method nanostructures such as: vanadium oxide - octadecyl amine - graphene, vanadium oxide - dodecyl amine - graphene and vanadium oxide – aniline - graphene (V-ODA-G، V-DDA-G، V-A-G). Then their structures and functions in propane dehydrogenation react...

2017
Kip B. J. Smeets

The effect of vanadium oxide as support and promoter on supported rhodium catalysts on the CO hydrogenation has been investigated at 0.15 and 4.0 MPa. Rh/V,O, reduced at 723 K has a good selectivity toward oxygenated products, especially C,-oxygenates, but has a low activity added as a promoter to catalysts consisting and stability. Vanadium oxide of rhodium supported on silica and alumina show...

Journal: :Dalton transactions 2013
Israel E Wachs

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...

2008
Daphne E. Keller Diek C. Koningsberger Bert. M. Weckhuysen

The effect of the point of zero charge (PZC) of the support oxide (Al2O3,Nb2O5, SiO2 and ZrO2) on the molecular structure of hydrated vanadium oxide specieshas been investigated with EXAFS spectroscopy for low-loaded vanadium oxidecatalysts. It was found that the degree of clustering (i.e., the V---V coordinationnumber) and the V---V distance increase with decreasing PZC of ...

2004
Jih-Mirn Jehng Israel E. Wachs

A series of V205/TiO 2/SiO 2 catalysts were structurally investigated by in situ Raman spectroscopy and chemically probed by methanol oxidation in order to determine the molecular structure-reactivity relationships of the V205/TiO 2/SiO 2 catalysts. Only surface TiO,. species are present on the 3% TiO 2 /S iO 2 catalysts, and the surface TiO x species as well as bulk TiO 2 (anatase) particles c...

Journal: :Dalton transactions 2013
Carlos A Carrero Christopher J Keturakis Andres Orrego Reinhard Schomäcker Israel E Wachs

The oxidative dehydrogenation (ODH) of propane to propylene by supported vanadia catalysts has received much attention in recent years, but different reactivity trends have been reported for this catalytic reaction system. In the present investigation, the origin of these differing trends are investigated with synthesis of supported V/SiO2, V/TiO2, and V/Al2O3 catalysts prepared with three diff...

Journal: :Chemical communications 2005
Qingmin Ji Toshimi Shimizu

An iced lipid nanotube has been employed as a template to perform sol-gel transcription of transition metal alkoxides in the absence of solution catalysts, giving titania, tantalum oxide and vanadium oxide nanotubes in aqueous dispersions.

2008
M. Olga Guerrero-Pérez Taejin Kim Miguel A. Bañares Israel E. Wachs

A series of bulk oxides (Sb2O3, Sb2O4, VSbO4, and V2O5) and alumina-supported oxides (Sb-O, V-O, and Sb-V-O) were synthesized by conventional methods. The resulting catalysts were characterized with XRD, BET, Raman, and CH3OH-temperature programmed surface reaction (TPSR) spectroscopy. XRD and Raman spectroscopy confirmed that the bulk oxides are present as crystalline phases and the alumina-su...

2008
Taejin Kim Israel E. Wachs

A series of supported V2O5/Al2O3 catalysts were synthesized by incipient wetness impregnation with vanadium isopropoxide in isopropanol solutions and subsequent calcination. The vanadium surface density was varied from 0.3 to 11.4 V atoms/nm2 spanning the sub-monolayer and above-monolayer regions. The resulting supported vanadium oxide catalysts were physically characterized with in situ Raman ...

Journal: :Zeitschrift für Physikalische Chemie 1978

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