The "Reactor-STM": A scanning tunneling microscope for investigation of catalytic surfaces at semi-industrial reaction conditions

An instrument is introduced that combines a scanning tunneling microscope (STM) and a small volume (300µl) 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 the 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 unaffected by moderate changes in the flow conditions during the scanning; and (3) that imaging of atomic steps is possible on a Co(0001) surface in a reactive environment at room temperature and at elevated temperatures. Furthermore, it is observed, that the step mobility on Co(0001) is strongly enhanced in the presence of H₂.