The mixed metal oxides CoAl2O4 and NiAl2O4 were prepared in a high surface
area form by using a sol-gel method which involves hydrolysis of cobalt-alu
minium and nicker-aluminium isopropoxides. The resulting gels were calcined
at 673 K to yield the corresponding spinel-type metal oxides. Powder X-ray
diffraction was used to confirm spinel formation. Nitrogen adsorption-deso
rption measurements have shown the materials obtained to be highly porous.
The BET surface area was found to be 240 m(2)g(-1) for CoAl2O4 and 255 m(2)
g(-1) for NiAl2O4. Both materials showed a unimodal distribution of pore ra
dii, where the most frequent pore radius is 5 nm for cobalt aluminate and 3
nm for nickel aluminate.