DOPED-ZRO2 AEROGELS - CATALYSTS OF CONTROLLED STRUCTURE AND PROPERTIES

Doped ZrO2 aerogels (characterised by TEM, DTA and Nz adsorption) have been prepared and catalytically tested in CO/CO2 hydrogenation [1] an d CH4 oxidation [2]. The primary aerogels showed cross-linked clusters of(X-ray) amorphous particles smaller than 5 nm which led to well-dev eloped mesoporous solids with an average pore size of about 10 nm and high surface area (up to 250 m(2)g(-1)) [1]. Cu/ZrO2 aerogels (known t o be very active and selective towards methanol synthesis in CO hydrog enation without predominant formation of alkanes even at higher temper atures [1]) are now seen to show these effects even more clearly in CO 2 hydrogenation. In methane oxidation, both Rh/ZrO2 and Y2O3/ZrO2 were very active. Consideration is given to the nature of the active sites , the role of CO2 and metal/oxide interfaces and how an understanding of this reactivity can lead to better dispersed ZrO2.