CO2 hydrogenation over metal/zirconia catalysts CO

Metal/zirconia catalysts have attracted considerable interest for the hydro genation of carbon dioxide. Various preparation methods such as impregnatio n, co-precipitation, sol-gel synthesis, and controlled oxidation of amorpho us metal alloys have been used, leading to catalysts with very different pr operties. The catalytic behaviour of these materials is greatly influenced by the active metal and by the interfacial contact area between the metal a nd zirconia. Cu and Ag catalyse mainly methanol formation, while methane is formed over, e.g., Ni, Ru and Rh. Examples for less reactive metal constit uents are Pd, Rh, Pt and Au, catalysing simultaneously the formation of met hanol, carbon monoxide (by reverse water-gas shift reaction) and methane. T he structural and catalytic properties of the various catalysts are compare d and possible reaction pathways are discussed.