Hydrogen storage using mixed clathrates in porous media

With the growing attractiveness of hydrogen (H2) as a fuel source for tomorrow's mobility, the issue of H2 storage will become central, especially for the medium size storage as for example in gas station for vehicles. The unique density and diffusivity properties of H2 at ambient conditions make storage very difficult. Indeed, storage by liquefaction requires being at a temperature of -240°C. Another possibility is storage in a porous material by absorption and adsorption. Chemical absorption makes it possible to achieve good storage capacities but makes destocking more energy-intensive, while adsorption storage requires high pressures and low temperatures, which also represents a significant energy cost. Another solution consists in forming gas hydrates which are composed of cages formed of water molecules in which are trapped one or more gas molecules, here hydrogen. Hydrogen hydrates in water also named Clathrates are formed at very high pressure (≈2000 bar)[1]. Acid-type additives combined with co-promoters enhanced trapping with the formation of hydrates compatible with storage far mild conditions (70 bar, 0°C) [2]. Another way to overcome these limitations is the possibility of introducing confinement inside a porous material to reduce the pressure of formation of these hydrates such as in carbon porous [3]. This thesis will study experimentally the storage of hydrogen in the form of mixed hydrogen hydrates in porous media. The first objective is to define the conditions of formation of mixed hydrogen hydrates in these porous material by calorimetry measurements. The second objective is to compare the storage/destocking capacity for different porous medias, ranging from microporous to mesoporous. The characterization of porous material before/after formation of hydrates will make it possible to understand the effect of surface chemistry and/or porosity in order to propose a reaction mechanism. The Raman spectroscopy, performed at ISM, on the best systems will provide information on mixed hydrogen hydrates at micrometric scale and their compositions. Finally, this PhD work will allow to propose 1 or more additives/porous material system(s) capable of storing a concentration of hydrogen under defined pressure/temperature/cycling conditions. 
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[1] W.L. Mao, H. Mao, A.F. Goncharov, V.V Struzhkin, Q. Guo, J. Hu, J. Shu, R.J. Hem- ley, M. Somayazulu, Y. Zhao, Science (80-.) 297 (2002) 2247 LP –2249.
[2] T. Thuong Nguyen, C. Pétuya, D. Talaga, A. Desmedt, Frontiers in Chemistry, 8, (2020), 550862. 
[3] Mao, W. L. et al. Science 2002, 297, 2247–2249. 7. Anderson, R

Key words: hydrogen, storage, clathrates, thermodynamics, porous material 

• PhD director    Dr, DESMEDT Arnaud, Senior Research Scientist, Institut des Sciences Moléculaires ISM UMR5255 CNRS
• Ecole doctorale    Ecole Doctorale des Sciences Chimiques (EDSC), 
• IFPEN supervisors    Dr, BORDES Emilie, research engineer, emilie.bordes@ifpen.fr Dr SINQUIN Anne, research engineer, anne.sinquin@ifpen.fr 
• Student localization     IFPEN, 1 et 4 avenue de Bois-Préau, 92852 Rueil-Malmaison, France ISM Bordeaux, 351 Cr de la Libération, 33405 Talence, France (at least 9 months)
• Duration and start date    3 years, start on November 2023
• Employer    IFP Energies nouvelles (IFPEN), Rueil-Malmaison, France
• Qualifications    Master’s degree in physics/physical chemistry /geochemistry/process engineering
• Languages    French: required, English advanced