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Matériaux bi-fonctionnels pour applications catalytiques et piézoélectriques, à base d'oxydes de cérium, de lanthane et de langasite

Abstract : The present study deals with catalytic and piezoelectric materials in form of nanopowders or nanostructured thin films to be involved in gas sensor applications. The catalytic phases were first based on cerium dioxide and barium cerate phases. These phases were elaborated from sol gel routes and characterized by X-ray diffraction, Scanning electron microscopy and FTIR spectroscopy. Using home made device, catalytic conversion of methane into CO2 was performed: the conversion rate was determined from FTIR analyses of emitted gases. Lanthanum oxide and hydrated and carbonated oxide phases including hydroxycarbonate and oxycarbonate of lanthanum were elaborated and characterized: thermal decomposition was studied from thermal analyses, impedance spectrometry and FTIR spectroscopy in the temperature range 50° to 700°C. Langasite La3Ga5SiO14 (LGS) was chosen as being a performing piezoelectric phase, having high electromechanical coupling and high temperature piezoelectric properties, allowing its coupling with a catalytic phase working at high temperature (up to 600°C). Polycrystalline langasite was elaborated via a specific solid state reaction process, and thin films were obtained via sol gel route associated with spin coating deposition process. Finally lanthanum films were deposited on these LGS films to deliver bilayers La2O3 – LGS. These bilayers might be involved in acoustic wave devices.
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Submitted on : Monday, February 18, 2008 - 6:07:58 PM
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  • HAL Id : tel-00257241, version 1

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Khalid Ouzaouit. Matériaux bi-fonctionnels pour applications catalytiques et piézoélectriques, à base d'oxydes de cérium, de lanthane et de langasite. Mécanique [physics.med-ph]. Université du Sud Toulon Var, 2007. Français. ⟨tel-00257241⟩

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