Equipment, AAP 2019-2
Project leader: Juliette Blanchard
Adsorption isotherms (that is: quantity of adsorbed species on the oxide vs concentration of the species in solution once equilibrium is reached) play a key role in the characterization of the surface properties of porous oxides in solution. They provide essential information not only on the adsorption capacity or on the number of active sites but also on the heat of adsorption of molecules on pore surface, hence giving access to information on the strength of interaction between the probe molecule and the surface. This information is especially valuable for the characterization of the strength of acid or basic sites that is strongly correlated with their catalytic properties for a given application. It can also be useful to the comprehension of reaction mechanism: indeed, the competitive adsorptions of reactants, products and by-products, which can markedly affect the yield to the desired product, is governed by the adsorption properties of each component
The characterization of adsorption capacity and surface properties of oxides at the liquid/solid interface is currently challenging, requires large amounts of oxide and is time consuming. Hence, one often revert to gas phase characterization, even if properties of oxides in gas and in liquid phase may differ significantly.
Therefore, we propose to design and build a set-up for the automated measurement of adsorption isotherms, at various temperatures and pressures. This set-up, once built, will be of interest to a large scientific community (catalysis, adsorption, depollution…)