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.

Rev. Sci. Instrum.

Rasmussen, P. B., Hendriksen, B. L. M., Zeijlemaker, H., Ficke, H. G., & Frenken, J. W. M. (1998). The "Reactor-STM": A scanning tunneling microscope for investigation of catalytic surfaces at semi-industrial reaction conditions. Rev. Sci. Instrum., 69, 3879–3884.