Abstract: Catalyst pellets with a high BET surface area can be formed from the compression of a submicron powder into the selected pellet shape, such as using a press that forms the pellet in a die. Catalysts of particular interest comprise a ceramic material with an elemental metal coating. A low temperature plasma treatment can be used to achieve desired surface modification. Catalysts are described that have high selectivities in ethylene epoxidation reactions run over long time periods. The improved catalysts are based upon catalyst materials, such as ytrria coated with silver, with high selectivities. High BET surface areas can be achieved by using a particulate ceramic support material.