The use of pi interactions in the development of ultra-stable hydrophobic heterogeneous catalysts – PICATA

Heterogeneous catalytic processes not only control the transformation of oil into petrol and petrochemicals, but also the mass production of commodity and fine chemicals, as well as most of the new biomass-derived chemicals and energy vectors. Despite the variety of reactions and active phases involved, the synthesis of solid catalysts almost exclusively involves covalent and strongly polarized ionic bonds. In the case of supported metal nanoparticles (M NPs), those are generally grown at the support surface by the controlled reduction of a chemically grafted species. Hydroxyl groups are commonly used as anchoring points for reaction with the metal precursor, so that the metal atom becomes covalently bound to the oxide surface via an oxygen atom. Hence even carbon supports are first oxidized in order to generate terminal oxygenated functions and take advantage of this covalent bonding.
However, the rise of new molecular structures such as graphene opens up new opportunities for the homogeneous distribution of metal catalysts over pristine support surfaces via a direct non-covalent interaction with the aromatic rings. PICATA aims at switching from a covalent to a non-covalent approach for the synthesis of metal catalysts and electrocatalysts supported on graphene and related graphitic materials.
In a first part, PICATA will target one-step, bottom-up synthetic methods that can efficiently decorate pristine polyaromatic-based surfaces with metal nanoparticles, upon direct reduction of metal complexes in pi interaction with the surface. The project will thus focus on determining the synthesis conditions, as well as the type of metal complexes, that allow to get high dispersions of some (electro)catalytically active phases of noble and non-noble metals over hydrophobic carbon-based surfaces.
In a second part, PICATA will evaluate the potential of those hydrophobic M-graphene nanocomposites in some of the most challenging reactions of this Century related to chemicals and energy, such as hydrogen-mediated low temperature oxidations, alkyne partial hydrogenation and electrocatalytic reactions involved in proton-exchange membrane fuel cells and solid alkaline fuel cells, and the Fischer-Tropsch reaction. PICATA will further optimize M-graphene nanostructures, considering in particular the synthesis of alloy NPs, aiming at developing new, more durable processes for those applications.