Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide

Novel gold catalysts were prepared by coprecipitation from an aqueous solution of HAuCl4 and the nitrates of various transition metals. Calcination of the coprecipitates in air at 400 °C produced ultrafine gold particles smaller than 10 nm which were uniformly dispersed on the transition metal oxides. Among them, Auα-Fe2O3, AuCo3O4, and AuNiO were highly active for H2 and CO oxidation, showing markedly enhanced catalytic activities due to the combined effect of gold and the transition metal oxides. For the oxidation of CO they were active even at a temperature as low as −70 °C.