The effect of the support in constraining the formation and defining t
he structure of bimetallic particles has been considered. Alumina and
NaY zeolite supported platinum and cobalt bimetallic catalysts are ill
ustrated to rationalize this effect. The surface composition and dispe
rsion of the bimetallic particles are further correlated with the cata
lytic activity of bimetallic catalysts in CO hydrogenation.