High-Pressure Scanning Tunneling Microscopy of a Silver Surface during Catalytic Formation of Ethylene Oxide

The active state of a catalyst: A high‐pressure scanning tunneling microscope (STM) was used to bridge the pressure gap for the Ag‐catalyzed ethylene epoxidation. An active oxygen species on an Ag(111) single crystal was characterized under ultrahigh vacuum conditions. The same species was identified with STM in an ethylene/oxygen mixture (see picture). In the STM cell the formation of ethylene oxide was detected.