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AbstractAbstract
[en] In the context of the energy transition, there is an urgent need to control the polluting emissions of means of transportation, housing, but also of the industrial sector. This thesis work deals with the study of the electrochemical reduction of CO2 in aqueous and organic media using nanostructured semiconductor photoelectrodes in the presence of organometallic electrocatalysts free of precious metals, based on iron, cobalt and nickel. The first part of our work deals with the elaboration, the nanostructuring, and the functionalization (doping, deposition of nanoparticles and functional thin films) of photoelectrodes based on TiO2 and NiO nanotubes systems. A set of organometallic complexes with electrocatalytic properties has also been synthesized and systematically characterized in order to identify the best candidate for CO2 electroreduction. One of the challenges lies in the identification of chemically and thermodynamically stable systems that are sufficiently efficient to reduce the CO2 molecule, and particularly selective to yield a limited number of high value-added reduction products that can be used in the chemical industry or as synthetic fuels. The methods used in this work to elaborate the semiconductor photoelectrodes are electrochemical anodization in acidic medium for TiO2 and NiO, atomic layer deposition (ALD) for the elaboration of functional thin films with light absorption properties (Sb2S3) and co-precipitation of the components of a photoactive material on a current collector for nickel oxide. The synthesis and characterization of molecular complexes with electrocatalytic properties using ligands of the cyclam, tren and clathrochelate family have also been performed. Molecular chemistry offers the advantage of being able to design tailor-made compounds by adjusting their electronic, geometrical and structural properties, allowing in particular their functionalization by physisorption or chemisorption (e.g. electro-grafting) on the surface of solid electrodes. (author)
[fr]
Dans le cadre de la transition energetique, un besoin urgent de controler les emissions polluantes des moyens de transport, des logements, mais egalement du secteur industriel s'impose. Ce travail de these porte sur l'etude de la reduction electrochimique du CO2 en milieux aqueux et organiques a l'aide de photoelectrodes semiconductrices nanostructurees en presence d'electrocatalyseurs organometalliques exempts de metaux precieux, a base de fer, de cobalt et de nickel. Une premiere partie de nos travaux porte sur l'elaboration, la nanostructuration, et la fonctionnalisation (dopage, depot de nanoparticules et de couches minces fonctionnelles) de photoelectrodes basees sur des systemes constitues de nanotubes de TiO2 et de NiO. Un ensemble de complexes organometalliques a proprietes electrocatalytiques a egalement ete synthetise et caracterise de maniere systematique afin d'identifier le meilleur candidat pour l'electroreduction du CO2. L'un des challenges reside dans l'identification de systemes stables d'un point de vue chimique et thermodynamique, suffisamment performants pour reduire efficacement la molecule de CO2, et particulierement selectifs pour aboutir a nombre restreint de produits de reduction a haute valeur ajoutee, pouvant etre utilises dans l'industrie chimique ou en tant que carburants de synthese. Les methodes employees dans ce travail pour elaborer les photoelectrodes semiconductrices sont l'anodisation electrochimique en milieu acide pour le TiO2 et le NiO, le depot de couches atomiques par ALD (Atomic Layer Deposition) pour l'elaboration de couches minces fonctionnelles aux proprietes d'absorption de lumiere (Sb2S3) et la co-precipitation des composants d'un materiau photoactif sur un collecteur de courant concernant l'oxyde de nickel. La synthese et la caracterisation de complexes moleculaires aux proprietes electrocatalytiques utilisant des ligands de la famille des cyclam, tren et clathrochelates ont egalement ete realisees. La chimie moleculaire offre l'avantage de pouvoir concevoir des composes sur mesure en ajustant leurs proprietes electroniques, geometriques et structurales, permettant en particulier leur fonctionnalisation par physisorption ou chimisorption (electrogreffage par exemple) a la surface d'electrodes solides. (auteur)Original Title
Electrodes nanostructurees et electrocatalyseurs organometalliques exempts de metaux precieux pour l'electro(photo)reduction du CO2
Primary Subject
Source
6 Dec 2021; 217 p; 186 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; These de doctorat de l'universite Paris-Saclay, Specialite: Chimie
Record Type
Miscellaneous
Literature Type
Thesis/Dissertation
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Country of publication
CARBON COMPOUNDS, CARBON OXIDES, CATALYSIS, CATALYSTS, CHALCOGENIDES, CHEMICAL COATING, CHEMICAL REACTIONS, CORROSION PROTECTION, DEPOSITION, ELECTROCHEMICAL COATING, ELECTROLYSIS, ELEMENTS, FILMS, LYSIS, MATERIALS, METALS, NANOSTRUCTURES, NICKEL COMPOUNDS, ORGANIC COMPOUNDS, OXIDES, OXYGEN COMPOUNDS, PHYSICAL PROPERTIES, SURFACE COATING, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, TRANSITION ELEMENTS
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