Copper-silver bimetallic catalysts offer improved selectivities compared with silver alone in the direct epoxidation of ethylene. This bimetallic combination was previously identified by density functional theory calculations, and its performance advantage was verified in preliminary catalytic reactor experiments. We report here a more detailed investigation of the performance of monolith-supported silver and Cu-Ag bimetallic catalysts at different feed compositions and reaction temperatures. From these studies, information about activation energies and reaction orders for ethylene epoxidation was obtained. The superior performance of the Cu-Ag bimetallic catalysts prepared by sequential impregnation was demonstrated over a wide range of feed compositions. (c) 2005 Elsevier Inc. All rights reserved.