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Habilitation à diriger des recherches

NAno‐Composites par la recherche des équilibres.

Abstract : The synthesis of new nanometric structures, such as metal / oxide or metallic nanofoam material, presents a large interest for their potential applications in the separation of molecules, sensors, catalysis and drug delivery. However, the various methods of synthesis present numerous inconveniences, and a great deal of effort has recently been specifically devoted to the synthesis of catalysts to find new processes, which are less expensive and more environment-friendly. Recently, we have patented a new process for the elaboration of noble metal-based catalysts by low temperature oxidation of metallic precursors. The resulting material is a nanocomposite made of noble metal and transition metal oxide nanoparticles. The control over the nanocomposite properties, namely the morphology of the composite and the noble metal composition, which in turn affect the catalytic properties, requires the knowledge of the phases which are present in the metallic precursors, and the choice of an appropriate microstructure. It was therefore necessary to rely on well-established phase diagrams. These studies required the development of a specific methodology to produce reliable data. The discovery of new intermetallic compounds allowed for determining the phase equilibria of the metallic precursor systems, and the leading second patent application for the preparation of rare earths-based catalysts. The establishment of the binary systems Zr-Au, Ce-Au and Ce-Pt now offers new perspectives of processing of ternary and higher order alloys. By their multidisciplinary aspect, these studies led to a strong association of skills and they follow two ways of development: thermodynamic and structural investigations of metallic systems and integration of the active materials in gas sensors. The first way is academic; it offers numerous studies of precursor systems and contributes to the preparation of model catalysts for the understanding of reaction mechanisms. The second one concerns industrial applications, the objective aims at enhancing catalyst properties and manufacturing processes, and at developing gas sensors. In this presentation, some examples of studies illustrate what our approach was and how this work contributes to demonstrate that the development and the optimization of the processes need the knowledge of phase diagrams of metallic precursor systems. Particular attention is given to the binary system Zr-Au which is at the origin of these studies; the processing of Zr-Au alloys has therefore allowed the elaboration of active and original gold-based nanocomposites. The presentation will end by showing a project which aims at preparing platinum-based catalysts supported on a mixed oxide, and an example of an industrial application which concerns the realization of a carbon monoxide sensor for domestic use.
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Habilitation à diriger des recherches
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https://tel.archives-ouvertes.fr/tel-00655804
Contributor : Polytech Annecy-Chambéry Symme <>
Submitted on : Monday, January 2, 2012 - 3:13:46 PM
Last modification on : Friday, November 6, 2020 - 3:33:47 AM
Long-term archiving on: : Thursday, March 30, 2017 - 9:38:20 PM

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  • HAL Id : tel-00655804, version 1

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Marc Lomello-Tafin. NAno‐Composites par la recherche des équilibres.. Matériaux. Université de Savoie, 2010. ⟨tel-00655804⟩

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