Fine particle pure and supported iron oxide materials have been prepared by the aerogel approach. These particles have diameters in the range 50-300 nm. They were evaluated as catalysts in the fixed bed reactors (gas phase and supercritical CO2) for the partial oxidation of methanol. The products observed were dependent upon support and reactor temperature. For example, the pure iron oxide aerogel achieved greater than 70% selectivity to dimethyl ether over a temperature range 220-275 degrees C. if the reaction is carried out over 20% iron oxide on molybdenum oxide from 250 degrees C to 330 degrees C, the main product observed was formaldehyde. The results are related to the surface chemistry of the iron oxide aerogel, and are influenced by the surrounding support.