Catalysts for oxidn. of ethylene to ethylene oxide comprise 0.1-25 wt.% Ag on a porous refractory support. They are prepd. by impregnating the support with an Ag-contg. soln. in stage(s) and depositing metallic Ag on the support particles so that the concn. of Ag on and near the surface of the particles is greater than that in the interior of the particles.
