Hydrogen assisted recycling of polyolefins on acid/metallic bifunctional catalysts

Plastic recycling is gaining more and more attraction, not only to find a solution to fossil resources depletion, but also to prevent plastics from damaging environment and to limit health issues. As IFPEN intends to be a major actor of low carbon footprint circular economy, R&D work on plastic recycling is ongoing. Polyolefins (PO) -which are the most difficult polymers to convert selectively- present a similar chemical nature than long paraffins present in conventional oil. Thanks to the knowledge and the long experience acquired for petroleum conversion over the last decades, IFPEN is well positioned to identify potentially active and selective catalysts for plastics recycling and also to help understand the mechanisms at stake during their conversion.
Hydrogen assisted conversion process using bifunctional catalysts is an interesting way to orientate the hydrocracking of polymers towards the production of desired products. These bifunctional catalysts contain both an acid (zeolite) and a hydro/dehydrogenating (metal) function. The zeolite properties (structure, acidity, pore size), the metal nature, the metal/acid ratio and the proximity between the metal and acid functions determine the selectivity of the PO conversion. Despite a strong similarity between PO and long alkanes present in petroleum, the specificity of polymers and in particular of PO (chain lengths distribution, crystallinity…), their diversity (LDPE, HDPE, PP…) as well as the additives they contain, will probably lead to different behaviors in presence of similar catalysts. The aim of this work is to propose a selective catalytic system for the conversion of PO into products that can be used in petrochemical processes to favor circular economy. A multidisciplinary work will be carried out, including the study of different zeolitic structures, different metals as well as a mechanistic study comparing the reactivity of various PO. The ultimate challenge will be to use the optimal catalyst to transform plastics from collection/sorting of real wastes.
Through this PhD, you will have the opportunity to acquire solid knowledge in different domains, namely zeolites, acid and metallic catalysis as well as polymer and catalysts characterization. This PhD will give you the possibility to work in a stimulating environment within a company which combines industry oriented and academic research in order to develop sustainable energies. The diversity of jobs represented at IFPEN will also give you the possibility to widen your general scientific background and to interact with multiple experts.

Keywords: recycling, polyolefins, polymers, zeolites, H2, circular economy, plastic wastes, selectivity, catalysis

• Academic supervisor    Research Director CNRS, Dr MONTEIL Vincent, CP2M, ORCID 0000-0003-3530-1789
• Doctoral School    206 - Ecole doctorale Chimie, Procédé, Environnement, lien sur le site
• IFPEN supervisor    Dr MAURY Sylvie, Researcher, sylvie.maury@ifpen.fr, ORCID 0000-0002-7742-8385
• PhD location    IFPEN, Solaize (69) and CP2M, Villeurbanne (69), near Lyon, France  
• Duration and start date    3 years, starting  fourth quarter 2023
• Employer    IFPEN, Solaize, France
• Academic requirements    University Master degree in relevant disciplines: chemical sciences, materials, chemical engineering
• Language requirements    Fluency in French or English