THE REACTOR STM - A SCANNING TUNNELING MICROSCOPE FOR INVESTIGATION OF CATALYTIC SURFACES AT SEMIINDUSTRIAL REACTION CONDITIONS

An instrument is introduced that combines a scanning tunneling microsc ope (STM) and a small volume (300 mu l) flow reactor, for the in situ study of catalytic surfaces at semi-industrial conditions. The tip is led through a gold membrane separating the reactor from the rest of th e STM. We show (1) that the scanning through the membrane is possible with no noticeable effect of the membrane; (2) that it is possible to image surfaces in a gas flow of 10 ml/min, and that the imaging is una ffected by moderate changes in the flow conditions during the scanning ; and (3) that imaging of atomic steps is possible on a Co(0001) surfa ce in a reactive environment at room temperature and at elevated tempe ratures. Furthermore, it is observed, that the step mobility on Co(000 1) is strongly enhanced in the presence of H-2. (C) 1998 American Inst itute of Physics. [S0034-6748(98)02311-9].