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Molybdenum Dioxide and Vanadium-Doped Molybdenum Dioxide Microcrystals in a Polymer Container.

Published online by Cambridge University Press:  01 February 2011

Alexandru C. Pavel ,
Dwight K. Romanovicz  and
John T. McDevitt
Alexandru C. Pavel
Affiliation:
Department of Chemistry & Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712–0165.
Dwight K. Romanovicz
Affiliation:
Department of Chemistry & Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712–0165.
John T. McDevitt
Affiliation:
Department of Chemistry & Biochemistry, University of Texas at Austin, 1 University Station A5300, Austin, TX 78712–0165.
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Abstract

Molybdenum dioxide and vanadium-doped molybdenum dioxide microcrystals were synthesized by a totally new method involving a redox-active monomer route. The two related dioxides had virtually identical crystal structures and the three precursors used in the process could be subsequently divided in two subgroups of two members each, based on their strong similarities in composition and crystal structure, respectively. Molybdenum trioxide (orthorhombic and hexagonal forms) and the vanadium-doped (10%, molar) molybdenum trioxide (hexagonal form) were used in the redox process with excess pyrrole, and at relatively high temperature (325°C) and long reaction time (12 days), formed a heterogeneous new type of organic-inorganic microcomposite. The new material could be described as a molybdenum dioxide crystal in a polymer box, with the size of the crystallite grain depending on the dimensions of the initial molybdenum trioxide grain and the ratio between the unit cell volumes of the initial and final oxide. The procedure took advantage of the relatively high reduction potentials of the Mo6+ and V5+ oxide surface centers towards the oxidative polymerization of pyrrole at intermediate temperatures, and the high catalytic activity of the metal cations in the molybdenum trioxide-based materials towards the total oxidation of the carbon atoms in the organic moiety, at elevated temperatures. This new synthetic route offers good perspectives as precursor composites for nanocrystal engineering in practical applications like heterogeneous catalysis, chemical sensing, nanostructured metallic catalysts, etc.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 847: Symposium EE – Organic/Inorganic Hybrid Materials , 2004 , EE13.46
Copyright
Copyright © Materials Research Society 2005

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References

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