Investigations on the adsorption and electrocatalytic oxidation of carbon monoxide on gold + palladium alloys

A bifunctional mechanism of electrocatalysis was found for the CO-oxidation at Au + Pd alloys. The synergetic effect works best at the 20% Au alloy. The different behaviour of An + Pd and Ag + Pd alloys was assigned to the formation of CO-induced ensembles of Pd-atoms at Au + Pd alloys with high gold content, which is possible due to a high mobility of Pd-atoms at the surface. As CO could be shown to react preferably with the Au-oxide species, the course of the energy of activation for the gas phase reaction might be understood on the-basis of geometric effects.