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PhD subjects

4 sujets IRAMIS

Dernière mise à jour :


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• Physical chemistry and electrochemistry

 

Ab initio simulation of catalysts for green chemistry

SL-DRF-24-0302

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie (NIMBE)

Laboratoire Structure et Dynamique par Résonance Magnétique (LCF)

Saclay

Contact :

Rodolphe POLLET

Patrick BERTHAULT

Starting date : 01-10-2024

Contact :

Rodolphe POLLET
CEA - DRF/IRAMIS/NIMBE/LSDRM

01 69 08 37 13

Thesis supervisor :

Patrick BERTHAULT
CEA - DRF/IRAMIS/NIMBE/LSDRM

+33 1 69 08 42 45

Personal web page : https://iramis.cea.fr/Pisp/rodolphe.pollet/

Laboratory link : https://iramis.cea.fr/nimbe/lsdrm/

Catalysis is today at the core of chemical industrial applications. For example, the conversion of nitrile to amide, which is relevant in pharmaceuticals, agrochemicals, synthetic chemistry and polymer chemistry, by hydration requires an efficient catalyst due to its slow kinetics. For environmental reasons, it is crucial to discover catalysts without transition metals, neither toxic nor corrosive, and cheap. One example of such catalyst is hydroxide choline.

During this thesis, the student will learn how to perform ab initio molecular dynamics simulations coupled with a method which can reconstruct the free-energy landscape of the hydration reaction for different aromatic nitriles in different in silico experimental conditions. He or she will also have to perform quantum chemistry calculations at a level that can describe all the required intra and intermolecular interactions. This theoretical approach has already been successfully used within our team to describe other chemical reactions in aqueous solution and will be applied to the innovative field of green chemistry.
Advanced 3D-printed metallic bipolar plates for PEMFC application

SL-DRF-24-0244

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie (NIMBE)

Laboratoire Innovation, Chimie des Surfaces Et Nanosciences (LICSEN)

Saclay

Contact :

Mélanie FRANCOIS

Bruno JOUSSELME

Starting date : 01-10-2024

Contact :

Mélanie FRANCOIS
CEA - DRF/IRAMIS/NIMBE/LICSEN

0169089191

Thesis supervisor :

Bruno JOUSSELME
CEA - DRF/IRAMIS/NIMBE/LICSEN

0169 08 91 91

Personal web page : https://iramis.cea.fr/nimbe/Phocea/Membres/Annuaire/index.php?uid=MF276647

Laboratory link : https://iramis.cea.fr/nimbe/LICSEN/

To meet the increasing energy demand and diversify energy resources, fuel cells emerge as a promising solution. This Ph.D work aims to contribute to the development of Proton Exchange Membrane Fuel Cells (PEMFCs), with a specific focus on bipolar plates (BPs) which ensure gas distribution and current collection. The first objectives are to design and manufacture stainless steel BPs using 3D printing (SLM - Selective Laser Melting) and to develop organic and inorganic anticorrosion coatings. Multiple channel architectures will be designed and characterized, including in-situ assessments with membrane-electrode assemblies (MEAs). Coatings will also be characterized, particularly in terms of their corrosion resistance through polarization methods. In the second phase, the aim is to integrate the optimized BPs with MEAs and thoroughly study the performance of PEMFCs using electrochemical techniques to gain fundamental insights into the mechanisms that limit PEMFCs performance.
Hybrid solid electrolytes for "all-solid" batteries: Formulation and multi-scale characterization of ionic transport

SL-DRF-24-0634

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie (NIMBE)

Laboratoire d’étude des éléments légers (LEEL)

Saclay

Contact :

Saïd Yagoubi

Thibault CHARPENTIER

Starting date : 01-10-2024

Contact :

Saïd Yagoubi
CEA - DRF/IRAMIS/NIMBE/LEEL

+ 33 1 69 08 42 24

Thesis supervisor :

Thibault CHARPENTIER
CEA - DRF/IRAMIS/NIMBE/LSDRM

33 1 69 08 23 56

Personal web page : http://iramis.cea.fr/Pisp/said.yagoubi/

Laboratory link : http://iramis.cea.fr/nimbe/leel/

More : http://iramis.cea.fr/nimbe/lsdrm/

Lithium-ion batteries, widely present in our daily lives, have revolutionized portable applications and are now used in electric vehicles. The development of new generations of batteries for future applications in transport and storing electricity from renewable sources is therefore vital to mitigating climate change. Lithium-ion technology is generally considered as the preferred solution for applications requiring high energy density, while sodium-ion technology is particularly attractive for applications requiring power.

However, the intrinsic instability of liquid electrolytes results in safety issues. Faced with the requirements concerning the environment and safety, solid-state batteries based on solid electrolytes can provide an effective solution while meeting battery energy storage needs. The barriers to overcome allowing the development of all-solid-state battery technology consist mainly in the research of new chemically stable solid electrolytes with good electrical, electrochemical and mechanical performance. For this goal, this thesis project aims to develop “polymer/polymer” and “ceramic/polymer” composite solid electrolytes with high performance and enhanced safety. Characterizations by electrochemical impedance spectroscopy (EIS) will be carried out in order to understand the cation dynamics (by Li+ or Na+) at the macroscopic scale in composite electrolytes, while the local dynamics will be probed using advanced techniques of Solid-state NMR (23Na / 7Li relaxation, 2D NMR, in-situ NMR & operando). Other characterization techniques such as X-ray and neutron diffraction, XPS, chronoamperometry, GITT ... will be implemented for a perfect understanding of the structure of electrolytes as well as aging mechanisms at the electrolyte / electrolyte and electrolyte/electrode interfaces of the all-solid battery.

Key words: composite solid electrolyte, all-solid-state battery, interfaces, multiscale characterization, dynamics of Li + and Na + ions, electrochemical performance, solid-state NMR, X-ray / neutron diffraction.
Nanodiamond-based porous electrodes: towards photoelectrocatalytic production of solar fuels

SL-DRF-24-0426

Research field : Physical chemistry and electrochemistry
Location :

Service Nanosciences et Innovation pour les Materiaux, la Biomédecine et l’Energie (NIMBE)

Laboratoire Edifices Nanométriques (LEDNA)

Saclay

Contact :

Jean-Charles ARNAULT

Hugues GIRARD

Starting date : 01-10-2024

Contact :

Jean-Charles ARNAULT
CEA - DRF/IRAMIS/NIMBE/LEDNA

01 68 08 71 02

Thesis supervisor :

Hugues GIRARD
CEA - DRF/IRAMIS/NIMBE/LEDNA

0169084760

Personal web page : https://iramis.cea.fr/nimbe/Phocea/Membres/Annuaire/index.php?uid=jarnault

Laboratory link : https://iramis.cea.fr/nimbe/ledna/

Among nanoscale semiconductors, nanodiamonds (ND) have not been really considered yet for photoelectrocatalytic reactions in the energy-related field. This originates from the confusion with ideal monocrystalline diamond featuring a wide bandgap (5.5 eV) that requires a deep UV illumination to initiate photoreactivity. At the nanoscale, ND enclose native defects (sp2 carbon, chemical impurities such as nitrogen) that can create energetic states in the diamond’s bandgap decreasing the light energy needed to initiate the charge separation. In addition, the diamond electronic structure can be strongly modified (over several eV) playing on its surface terminations (oxidized, hydrogenated, aminated) which can open the door to optimized band alignments with the species to be reduced or oxidized. Combining these assets, ND becomes competitive with other semiconductors toward photoreactions. The aim of this PhD is to investigate the ability of nanodiamonds in reducing CO2 through photoelectrocatalysis. To achieve this goal, electrodes will be made from nanodiamonds with different surface chemistries (oxidized, hydrogenated and aminated), either using a conventional ink-type approach or a more innovative one that results in a porous material including nanodiamonds and a PVD-deposited matrix. Then, the (photo)electrocatalytic performances under visible illumination of these nanodiamond-based electrodes toward CO2 reduction will be investigated in terms of production rate and selectivity, in presence or not of a transition metal macrocyclic molecular co-catalyst.

 

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