Heterogeneous Catalysis

Synthesis of cobalt, nickel and alloy nanoparticles: application in catalysis.

The last decades have shown that nanocrystals (NCs) can play an important role in many fields such as biology, catalysis and magnetism. From a sustainable point of view, it is necessary to limit the use of rare metals (platinum, palladium, etc.) as catalysts. To achieve interesting electronic and chemical properties, the nano-object must be carefully designed, i.e. its shape, size, phase and composition. Since 2015, MP and MB in collaboration with the MONARIS Laboratory, (Prof. Christophe Petit and Dr. Caroline Salzemann), have been studying the synthesis of cobalt and nickel nanoparticles starting from easily accessible simple low valence precursors. The aim of these studies is to obtain nano-objects in a controlled and reproducible manner under mild conditions. During this collaboration, ANR NUMEN (2018-2022), the mechanism of NPs formation has been rationalized, as well as the development of an ultra fast and milder synthesis still with the same complex in THF in the presence of fatty alcohol as surfactant. This type of surfactant has the advantage of being inexpensive and, above all, easily exchangeable with amines, acids or even phosphines. Thanks to this synthesis, we are considering, within the framework of the ORCHESTRAL project (ISIM 2021 funding), the synthesis of chiral cobalt NPs either by ligand exchange after the synthesis, or by using chiral alcohols of the helicene type during the synthesis at room temperature. The same strategy is also envisaged in the framework of the ANR CHIRNATION for the development of chiral gold NPs and their application in catalysis. The use of chiral alcohols derived from biomass is also envisaged.

Synthesis of iron nanoparticles. 

In collaboration with Pr E. Guenin and Dr D. Luart (UTC, Compiègne), JO and AP aim to develop C-H amination reactions of simple arenes and alkenes in water using stable iron nanoparticles (Fe-NPs). Several types of Fe-NPs, with various structures and coatings, will be prepared by environmentally friendly syntheses, without toxic solvents and in the presence of biocompatible reagents as stabilisers. They will be evaluated as reusable catalysts for the synthesis of primary amines. This direct amination will involve the action of ammonia-type radical cations, generated in-situ by single electron transfer (SET) from hydroxylamines and Fe-NP. In addition, this project aims to transpose these heterogeneous C-H amination reactions to flow chemistry, as well as in the cascade process to quinoline derivatives from in-situ formed anilines.

Heterogeneous flow chemistry processes for the functionalization of furfural derivatives. 

In order to consider a scale-up of C-H functionalization processes of furfural, currently in collaboration with Dr. J. Blanchard, JO is transposing some of the known palladium processes into flow chemistry. In order to have a sustainable strategy, the use of a tubular reactor containing the catalyst in heterogeneous phase. Thus, combining the advantages of flow chemistry with those of heterogeneous catalysis, by grafting the PdX2 complex onto an oxide support (such as silica or alumina), will allow the development of cleaner and safer furfural functionalization processes.