New integrated concept for lignin conversion to chemicals using confined Palladium Nanoparticles – NANOTRAP

NANOTRAP aims at developing a new concept for deconstructing complex biopolymers like lignin into valuable chemicals.
Indeed the valorization and refining of biomass still represent a great challenge from both scientific and economical points of view. The main requirements for the full development of biorefineries include the exhaustive biomass components recovery, their efficient transformation into added-value products, at a competitive cost. The transformation of biomass often involves the presence of a catalyst, preferentially a heterogeneous catalyst. Metal-based heterogeneous catalysts are very important for biomass transformation: they can enhance the reactivity of the biopolymer while driving the transformation to specific selectivity. For an efficient use of such catalysts, some of the prerequisites are a deep understanding on the action of the catalyst on the biopolymer reactant, and an easy separation and recovery of the catalyst from the reaction mixture. This is the general context of NANOTRAP concept.
This project proposes to study the reactivity/transformation of various lignins using Pd-based nanocatalysts, specifically prepared and added just after to the flow-reactor where biopolymer transformation occurs, and coupled to magnetic separation at outlet of reaction zone.
More precisely, Pd-nanoparticles (PdNPs) of controlled sizes and shape will be prepared and supported on metal oxides, to increase the surface area, to be used in reactive flow conditions, and to be magnetically recovered. For that PdNPs/Fe3O4/MOx based catalysts will be developed. An innovative supercritical flow technology will be used, that offers the possibility to make in-situ and/or ex-situ a functionalization through a one-pot preparation of desired structures/compositions of the catalysts. The way the catalysts act during biopolymer transformation can be studied in the same reactor just after catalysts synthesis and injection to the reaction chamber, with the help of in-situ home-made spectroscopy techniques. This technology will offer a unique opportunity to deeply understand the real role of the Pd-nanocatalysts independently of side recombination reactions of intermediates or products. Influence of various reaction conditions of temperature and pressure, in oxidative, reductive or inert atmosphere will be studied in independent closed reactors before transferring to trickle-bed reactors for finer evaluation. Recovery of the Pd-nanocatalysts will be performed by magnetically trapping. Sedimentation studies will be realized in batch conditions then in flow conditions to reinject the recovered catalysts in the transformation loop possibly by reverse flux. A comprehensive modeling will be done to help designing properly the magnetic trap in order to use the Pd-nanocatalysts under flow conditions, which would be the definitive objective of NANOTRAP.
To reach this objective, 3 academic laboratories, namely IRCELYON, ICMCB and LGPC, will join their efforts. They share their complementary expertise in catalyst preparation, catalysis for biomass upgrading, in-situ techniques, kinetics, chemical engineering, reactor design and conceptualization.
In fine NANOTRAP should allow to prove the concept that can be used in the future in biorefineries for an efficient catalytic biomass valorisation into platform chemicals.