نتایج جستجو برای: nanostructured vanadium catalysts

تعداد نتایج: 56195  

2015
Mohammadreza Shokouhimehr Masahiko Arai

This review is focused on the strategies and designs of magnetic nanostructured catalysts showing the enhanced and sustainable catalytic performances for the heterogeneous reduction of nitoaromatics. Magnetic catalysts have the benefits of easy recovery and reuse after the completion of the reactions and green chemical processes. Magnetic separation, among the various procedures for removing ca...

2009
Christian Lorber

The synthesis and solution and solid-state structural characterization of a family of amine bis(phenolate) [ONNO]-vanadium complexes is reviewed. These compounds have oxi dation states ranging from vanadium(II) to vanadium(V), and were evaluated as olefin polymerization catalysts. In association with EtAlCl2 cocatalyst, we studied the homo polymerization of ethylene, propene, and 1-hexene, as w...

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...

2011
Yanyi Liu Dawei Liu Qifeng Zhang Guozhong Cao

Boosted by the rapid advances of science and technology in the field of energy materials, Li-ion batteries have achieved significant progress in energy storage performance since their commercial debut in 1991. The development of nanostructured electrode material is regarded as one of the key potentials for the further advancement in Li-ion batteries. This feature article summarizes our recent e...

2008
Ying Wang Guozhong Cao

Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. This Review describes some recent developments in the synthesis and characterization of nanostructured cathode materials, including lithium transition metal oxides, vanadium oxides, manganese oxides, lithium ph...

Journal: :Journal of the American Chemical Society 2010
Julie E Molinari Israel E Wachs

Recent debates over the active site structure of supported vanadia/silica catalysts have suggested the existence of a surface vanadium peroxo-oxo "umbrella" structure. This study definitively demonstrates with Raman and UV-vis spectroscopy that the surface vanadia peroxo-oxo umbrella-like structure is not present for both hydrated and dehydrated supported vanadia catalysts such as supported van...

Journal: :Chemical communications 2010
Victor Chechik Marco Conte Trevor Dransfield Michael North Marta Omedes-Pujol

During asymmetric cyanohydrin synthesis catalysed by vanadium(V)oxo(salen) complexes, the catalysts are reduced to vanadium(IV)oxo(salen) as determined by EPR spectroscopy; the reducing agent is cyanide which is oxidised to cyanogen via a non-radical mechanism.

2007
Guoan Du Sangyun Lim Mathieu Pinault Chuan Wang Fang Fang Lisa Pfefferle Gary L. Haller

Vanadium oxide grafted on mesoporous silica SBA-15 has been synthesized using a controlled grafting process. Its structure has been thoroughly investigated using different characterization techniques, including N2-physisorption, X-ray diffraction, transmission electron microscopy (TEM), Raman spectroscopy, H2 temperature-programmed reduction, X-ray absorption near-edge structure (XANES), and ex...

2017
Alette G.J. Ligtenbarg Ronald Hage Ben L. Feringa

Vanadium haloperoxidases catalyse the oxidation of halides leading to halogenation of substrates or, in the absence of suitable substrates, to oxidation of hydrogen peroxide into singlet oxygen and water. Furthermore, V-haloperoxidases are capable to give enantioselective sulfoxidation under the appropriate conditions. The most interesting model compounds that have been synthesised and studied ...

2007
Xiao-Wei Chen Zhenping Zhu Michael Hävecker Dang Sheng Su Robert Schlögl

A vanadium oxide-carbon nanotube composite was prepared by solution-based hydrolysis of NH4VO3 in the presence of carbon nanotubes. The carbon nanotubes induce the nucleation of the 1D vanadium oxide nanostructures, with the nuclei growing into long freestanding nanorods. The vanadium oxide nanorods with the lengths up to 20 μm and the widths of 5–15 nm exhibit a well-ordered crystalline struct...

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