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Nanoélectrocatalyseurs d'or à morphologie contrôlée pour l'oxydation de molécules sondes : monoxyde de carbone et glucose

Abstract : Interfacial properties of metallic nanoparticles depend on their size, morphology, composition and the reaction medium. These unexpected properties offer numerous applications as in electrocatalysis. Unsupported nanoparticles are required for studying and understanding the intrinsic surface reactivity of nanocatalysts in interaction with various molecules such as carbon monoxide, glucose, glycerol and oxygen. Unsupported gold based shape controlled nanoparticles (nanorods, octahedral, etc.) were prepared by the seed mediated method. Physico-chemistry characterizations (UV‒visible, transmission electron microscopy, etc.) permitted to observe nanoparticles with expected shape and size. Electrochemical characterizations as underpotential deposition of lead by cyclic voltammetry revealed the crystallographic surface orientation and the presence of high Miller index (by a reductive desorption of 4‒mercaptobenzoic acid). Surface oxidation of such nanoparticles in supporting electrolyte depends on the surface crystallographic orientations. The oxidation of carbon monoxide on gold nanospheres with a mean diameter size of 24 nm was observed at a low potential as 0.2 V vs. RHE. Gold nanomaterials prepared in presence of silver and palladium showed a low onset potential of glucose oxidation (0.2 V vs. RHE, 100 mV lower than a pure gold nanomaterials). In alkaline medium, oxygen reduction and glucose oxidation reactions on core-shell (Au@Pd and Au@PdAg) showed 0.65×10−3 mA cm−2 and 0.55 V vs. RHE as an exchange current density and onset oxidation potential respectively. The gold core as well as the silver shell have thereby a benefit effect on these two reactions by decreasing the respective overpotential.
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Submitted on : Thursday, June 11, 2020 - 10:33:18 AM
Last modification on : Wednesday, October 14, 2020 - 4:11:04 AM


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  • HAL Id : tel-02864532, version 1



Nolwen Mayet. Nanoélectrocatalyseurs d'or à morphologie contrôlée pour l'oxydation de molécules sondes : monoxyde de carbone et glucose. Chimie analytique. Université de Poitiers, 2019. Français. ⟨NNT : 2019POIT2313⟩. ⟨tel-02864532⟩



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