(234f) Highly Active and Selective Au/MOx (M = Fe, Co) Catalysts for the Dehydrogenation of Naphthenes

Gold supported on metal oxides are versatile catalysts with growing interest for many reactions. Besides CO oxidation and water-gas shift reactions, their application for methanol steam reforming, the liquid phase hydrogenation of α,β-unsaturated aldehydes and ketones, the selective oxidation of alcohols and the direct synthesis of hydrogen peroxide from H₂ and O₂ have been reported recently.^1,2 In contrast to palladium or platinum, gold catalysts have the advantage to be less expensive and more stable under reaction conditions. Their high activity and stability are related to the formation of small gold clusters with a strong gold-metal oxide interaction.^3,4 Here we report of the catalytic dehydrogenation of cyclohexane and decalin over Au/MO_x (M = Co, Fe) catalysts. Monodisperse cobalt and iron oxide supports with spherical, cubic and octahedral shapes were prepared by hydrothermal and thermal decomposition methods. Highly dispersed gold clusters were deposited on the metal oxide supports by deposition-precipitation in the presence of urea. Cobalt and iron oxide supported gold catalysts show high activity and selectivity for benzene and naphthalene formation. The formation and stabilization of small gold clusters, and consequently the catalytic activity, were found to depend strongly on the size and shape of the metal oxide supports.

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