TAilored Nanoparticles for the selective catalytic Oxidation of POLy-alcohols – TANOPOL

Novel catalysts and eco-efficient processes are required to use alternative feedstock such as biomass-derived poly-alcohols. Several challenges have to be faced during the development of those catalysts. Firstly, cheap and abundant metals should replace noble metals or toxic ones. Secondly, for obvious economic and environmental reasons, the selectivity towards a given highly valuable product should be the highest possible, despite the variety of hydroxyl functional groups on a given oxygenated compound derived from the biomass feedstock. In the case of the selective dehydrogenation of polyols, it is hard to dehydrogenate selectively secondary alcohols in presence of primary ones. It is also challenging to avoid the complete oxidation of primary alcohols to carboxylic acids. Original strategies have to be developed to improve both the activity and selectivity of catalysts. The first strategy proposed in this project is based on the use of nanoparticles with well-defined morphologies to take advantage of the shape-sensitivity of some reactions. The second one consists in blocking some active sites by the adsorption of organic molecules (such as thiols or amines) on metallic particles to enhance the selectivity, but little is known on the exact role of those ligands.
For liquid-based syntheses, the control of the shape of nanoparticles is usually performed by the privileged adsorption of capping ligands on some crystal facets and the judicious choice of the growth conditions. In some cases, particles exhibiting open facets stabilized by capping ligand can be obtained. Then, those nanoparticles combine the advantages of the shape-controlled nanoparticles with the potential enhancement of the selectivity through the adsorption of organic molecules. They could be directly used as selective and efficient catalysts. However, shape control is often realized through an empirical approach and several experimental parameters must be varied in a systematic way to determine the optimal conditions. This empirical approach is costly, time-consuming and restricts a sensible screening of structure/properties relationships. The fast screening and development of those original catalysts require a comprehensive understanding of the factors governing the final shape of the nanoparticles but also of their activity towards alcohols dehydrogenation. Modeling coupled with detailed experimental characterizations is essential to provide the required insights in the nanoparticles syntheses and their catalytic activity.
This proposal joins the efforts of 4 academic partners (i.e. ITODYS, LPCNO, LC-ENSL and IRCELYON) with highly recognized complementary expertise. Two PhD students and one post-doc will also contribute to this project. To ensure a strong synergy between experimental and theoretical approaches, the two PhD students will use both approaches. The project is organized in three tasks with balanced scientific/technical skills between the partners: (WP 0) coordination; (WP 1 ) synthesis of a rich diversity of decorated nanoparticles with tailored shapes and capping agent; (WP 2) catalytic dehydrogenation of poly-alcohols using those novel catalysts. The realization of this project is expected to impact not only the domain of heterogeneous catalysis but also that of controlled nanoparticles synthesis, with potential applications in numerous fields, from magnetism to optics.