SLIMCAT is a collaborative project n°ANR-14-CE08-0019 funded by the French National Research Agency (ANR) for 4 years (2014-2018).
Challenge: “Stimulating the renewal of the industrial sector”.
The overall budget is 2.45 M€ for an ANR funding of 540 k€.
It is also labelled by AXELERA, the competitive cluster on Chemistry and Environment.
The rational understanding and prediction of chemical phenomena occurring at the solid-liquid interface (SLI) of alumina supported catalysts represent a double industrial challenge raised by the catalysts' preparation and the optimization of catalytic processes working in liquid water such as biomass conversion, Fischer-Tropsch (FT) synthesis. Moreover, γ-alumina is used as the industrial support in numerous catalytic processes particularly in the petrochemical and refining industry (including those previously cited). Regarding the active phase itself, cobalt is playing a central role in FT and hydrotreating (HDT) catalysts. In both cases, the improvement of the preparation (impregnation and drying) in presence of oxygenated organic molecules (additives) is crucial for maximizing the number of accessible metallic active sites and thus minimizing the number of cobalt atoms lost either in a refractory (oxide) phase or in the support.
Thanks to a multidisciplinary and bottom up approach, the SLIMCAT project aims thus at determining key molecular-scale descriptors tuning the SLI properties: pKa of hydroxyl sites of aluminas, spectroscopic/energetic/structural descriptors, interfacial energies, energy scale of interactions between cobalt precursors, oxygenated organic molecules and the alumina surface, molecular mechanisms at SLI… The oxygenated molecules chosen (polyols, ethers, carboxylic acids) are representative of additives present at the catalyst preparation stages and are also representative of chemical functions of biomass oxygenated derivatives present during the reaction.
In order to improve the design of future catalysts, we expect to furnish rational and innovative guides based on the revisited quantification of aluminas in water, the cobalt precursors speciation at alumina surfaces, the role and/or choice of oxygenated molecules orienting the cobalt speciation and stability of alumina in water, the optimized preparation parameters (impregnation/drying sequences in presence of additives).