Dynamics and molecular transport in boehmites, link "structure - dynamics"

Research division

Alumina remains the unavoidable catalyst support used in heterogeneous catalysis in the refining field. This material has a multi-scale hierarchical porosity that extends from nano to micron pores. It is obtained through calcination (topotactic) of boehmite pastes. Upstream, these pastes result from unit operations such as synthesis, drying, peptization, filtration and shaping (by drying, by extrusion). It has been shown that the porous structure of alumina is largely inherited from the structure of boehmite nano-crystal aggregates in aqueous phase.
One of the important challenges for these precursor materials of meso and macroporous catalytic supports is to better understand the relationships between porous texturing and molecular traffic. It has already been shown that the nature of the solvent (water, alcohol, toluene) and in particular its interaction with solid surfaces is a determining element in the texturing of the colloidal phases. In parallel, the dynamic properties of this solvent in the extrudates and / or the colloidal suspensions are directly related to the confinement imposed by the meso and macroporous porous network and its interfaces. The goal of this thesis is to conduct a true multi-scale analysis of the dynamics of the saturating solvent either on the concentrated boehmite suspensions or on the boehmite extrusions. One of the originalities of this work will be to rely on experimental representations of 3D texture, obtained during another thesis, for the interpretation of the experimental results and to deduce, if possible, rules of optimization of the molecular traffic for adjust the properties of the final alumina. The main tool that will be used is the low field NMR.

The thesis will be done at Sorbonne University as well as in partnership with IFPEN (Paris), ICPMS (Strasbourg) and CRMN (Lyon); the work will be carried out largely at the PHENIX laboratory (Paris).

Keywords: boehmite, NMR, porous medium, dynami, multi-scale

  • Academic supervisor    Dr, ROLLET Anne-Laure, Sorbonne Université, CNRS UMR 8234, PHENIX, ORCID : 0000-0001-6150-768X
  • Doctoral School    ED 388 - Chimie physique et chimie analytique de Paris Centre  http://ed388.sorbonne-universite.fr/fr/index.html
  • IFPEN supervisor    Dr, CHEVALIER Thibaud, Research Engineer, Physics and Analysis Division, thibaud.chevalier@ifpen.fr, ORCID : 0000-0002-8658-3694
  • PhD location    Sorbonne Université, CNRS UMR 8234, PHENIX, Paris, France 
  • Duration and start date    3 years, starting not earlier than November 2020
  • Employer    IFP Energies nouvelles, Rueil-Malmaison, France
  • Academic requirements    University Master degree in Physical sciences
  • Language requirements    Fluency in English
  • Other requirements    Good skills in physics and physico-chemistry, advanced knowledge in NMR will be an asset.
Encadrant IFPEN 
Ingénieur de recherche, Direction Physique et Analyse
Texte libre

IFP Energies nouvelles is a French public-sector research, innovation and training center. Its mission is to develop efficient, economical, clean and sustainable technologies in the fields of energy, transport and the environment. For more information, see https://www.ifpen.com. 
IFPEN offers a stimulating research environment, with access to first in class laboratory infrastructures and computing facilities. IFPEN offers competitive salary and benefits packages. All PhD students have access to dedicated seminars and training sessions.