Adsorption Deposition of Palladium Hexafluoroacetylacetonate on Porous Matrices in Supercritical CO2

The adsorption deposition of palladium hexafluoroacetylacetonate Pd(hfa)2 on porous supports (γ-Al2O3 and hypercrosslinked polystyrene, HCP) in supercritical CO2 is considered. The conditions for a transition of the Pd(hfa)2/CO2 system to a monophase region have been studied. Due to its reasonably high solubility in CO2, the palladium compound can be deposited at relatively low pressures (~8.5 MPa) in the system. The adsorption of Pd(hfa)2 on the given supports is well described by the Langmuir equation. An increase in the pressure in the system under isothermal conditions negatively affects the amount of adsorbed precursor because of the adsorption of CO2 and distribution offset in the system. The limiting adsorption increases at elevated temperatures in the system under isochoric conditions.