General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DRF-24-0239
Direction
DRF
Thesis topic details
Category
Condensed Matter Physics, chemistry, nanosciences
Thesis topics
Exploring the reactivity of oxide based catalysts by radiolysis
Contract
Thèse
Job description
In the context of the search for processes that are less polluting and more energy-efficient than current processes, it is interesting to produce high-stake molecules such as C2H4 by developing alternative synthesis routes to steam cracking, which is used in the majority of cases, but is energy-intensive and based on fossil resources. Processes such as photocatalysis, which relies on the use of light energy, seem an attractive way of generating these molecules of interest. In this context, we have already shown that the use of TiO2-based photocatalysts decorated with copper particles enables the production of ethylene from an aqueous solution of propionic acid, with a selectivity (C2H4/other carbonaceous products) of up to 85%.
However, photocatalysis kinetics can be slow, and it can take a long time to identify the best catalysts or catalyst/reagent pairs for a given reaction. So, in order to determine whether radiolysis, which relies on the use of radiation to ionize matter, can be an effective method of screening catalysts, initial experiments have already been carried out on catalyst (TiO2 or Cu TiO2)/reagent (propionic acid more or less concentrated) pairs, previously studied in photocatalysis. Initial results obtained by radiolysis are encouraging. In these experiments, only dihydrogen production was measured. A significant difference was observed in this production depending on the system: it was high during radiolysis of propionic acid with TiO2 nanoparticles, and significantly lower in the presence of Cu TiO2 nanoparticles, suggesting a different reaction path in the latter case, in line with observations made during photocatalysis experiments.
The aim of this thesis work will be to extend these initial results by synthesizing nanoparticles (catalysts), preparing reagent/catalyst mixtures, then irradiating them and measuring the various gases produced by gas-phase micro-chromatography, with special attention on ethylene. Particular attention will be paid to determining the species formed, especially transient ones, in order to ultimately propose reaction mechanisms accounting for the differences observed for the different reagent/catalyst pairs. Comparisons will also be made with results obtained by photocatalysis.
University / doctoral school
Sciences Chimiques: Molécules, Matériaux, Instrumentation et Biosystèmes (2MIB)
Paris-Saclay
Thesis topic location
Site
Saclay
Requester
Position start date
01/10/2024
Person to be contacted by the applicant
HERLIN Nathalie nathalie.herlin@cea.fr
CEA
DRF/IRAMIS/NIMBE/LEDNA
IRAMIS/NIMBE/LEDNA
Bât 522
CEA Saclay
911191 Gif-sur-Yvette Cedex
0169083684
Tutor / Responsible thesis director
LE CAER Sophie sophie.le-caer@cea.fr
CNRS
DRF/IRAMIS/NIMBE/LIONS
DRF/IRAMIS/NIMBE/LIONS
Bât.546
CEA Saclay
91191 GIf/Yvette
01 69 08 15 58
En savoir plus
https://iramis.cea.fr/Pisp/sophie.le-caer/
https://iramis.cea.fr/nimbe/LIONS
https://iramis.cea.fr/nimbe/LEDNA