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Reference : UMR8502-PASLAU-002
Workplace : ORSAY
Date of publication : Monday, April 12, 2021
Scientific Responsible name : Pascale LAUNOIS
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 September 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
Hydrogen is the carbon-free fuel par excellence because its combustion, or its use in fuel cells, emits only water. The recent discovery of high hydrogen contents in clay-rich rocks  underlines the potential of clays for hydrogen storage. Considering low-cost and green materials, such as clays, for hydrogen storage at room temperature and at moderate pressure could be an interesting perspective.
One could take advantage of the original properties of hydrogen when confined within small pores. Recently, a transition from a low-temperature, low-density phase to a high temperature, higher density phase was evidenced in graphitic Saran carbon, under moderate pressure . The high-density phase is characterized by a large proportion of ortho-H2 (with total molecular spin S = 1) which is forced to adopt a collective orientation to pack inside sub-nanometric pores. The density of the solid H2 phase stabilized by the adsorbent interaction reaches a larger value than that of the liquid state, a limit that was thought not possible to cross . It is now important to search for new materials aiming at stabilizing these solid phases. One aspect in this direction is to change the H2-adsorbent bonding interactions, by choosing clays with tuneable pore size.
The anisotropy and porosity of clay materials is primarily determined by the anisotropy of the clay particles themselves . An unprecedented range of aspect ratios (ratio R between the height H and diameter D of the clay particle), from 0.1 to 100, will be studied.
A comprehensive set of experimental methods (X-ray scattering, small angle neutron scattering, quasielastic and inelastic neutron scattering and adsorption measurements will be used, coupled with molecular dynamics simulations. Expected results are the determination of the particle and pore networks and of quantities of adsorbed hydrogen, the understanding of the retention mechanism, of thermodynamic properties in play and the analysis of the diffusion processes for H2 at the molecular level.
The thesis is a fundamental research thesis in connection with the energy issue. The PhD student should have a solid background in physics and be highly interested by experimental and numerical approaches.
 L. Truche et al., Earth Planet. Sci. Lett. 66, 315 (2018)
 R.J. Olsen et al., ACS Nano 11, 11617 (2017)
 V. Ting et al. ACS Nano 9(8) 8249 (2015)
 T. Dabat et al., Nature Comm. 10, 5456 (2019)
 E. Paineau and P. Launois, Nanomaterials From Imogolite: Structure, Properties, and Functional Materials. In Nanomaterials from Clay Minerals; Elsevier, 2019; pp 257–284
The PhD thesis will be directed by Pascale Launois (Laboratoire de Physique des Solides (LPS), Orsay, France) and co-directed by Laurent Truche (ISTerre, Grenoble, France) and Stéphane Rols (Institut Laue-Langevin, Grenoble). The PhD student will be based at LPS, Orsay and he/she will have to carry out missions at ISTerre and ILL at Grenoble.
Constraints and risks
Radioprotection (X-ray and neutron scattering)
The thesis is funded by the French Agence Nationale de la Recherche.
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