Doped-ZrO2 Aerogels: Catalysts of Controlled Structure and Properties

Doped ZrO2 aerogels (characterised by TEM, DTA and N2 adsorption) have been prepared and catalytically tested in CO/CO2 hydrogenation [1] and CH4 oxidation [2]. The primary aerogels showed cross-linked clusters of (X-ray) amorphous particles smaller than 5 nm which led to well-developed mesoporous solids with an average pore size of about 10 nm and high surface area (up to 250 m2g-1) [1]. Cu/ZrO2 aerogels (known to be very active and selective towards methanol synthesis in CO hydrogenation without predominant formation of alkanes even at higher temperatures [1]) are now seen to show these effects even more clearly in CO2 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.