Polystyrene microsphere-template method for textural design of alumina - an effective catalyst support for macromolecule conversion

Polystyrene microsphere-template method was used to prepare a range of hierarchically porous alumina samples. Different ways for creating hierarchical porosity were implemented, including mixing of alumina precursor with dry powder of PS microspheres and with PS water suspension, followed by extruding the resulting composite and its calcination. The samples were studied by BET technique, Hg porosimetry and scanning microscopy, mechanical strength of alumina pellets was also measured. In comparison with the dry method, the wet one gives pellets with a narrower distribution of macropores in size and the greater material mechanical strength. In whole the approach allows tuning textural parameters of hierarchically porous alumina samples in the following range: BET specific surface area 90-300m(2)/g, mesopore volume 0.30-0.65 cm(3)/g, total pore volume 0.50-1.20 cm(3)/g, mechanical crushing strength of 10-35 MPa. Ordered macroporosity of alumina was obtained by the impregnation of dry PS colloidal crystal by ethanol-water solution of aluminum oxalate; this method can be used only to produce small quantities or films of the material.