In Situ Scanning Tunneling Microscopy of the Dissociation of CO on Co(0001)

Abstract

The dissociation of CO, a crucial step in the cobalt-catalyzed Fischer–Tropsch synthesis, was investigated by in situ scanning tunneling microscopy on Co(0001) at CO pressures up to 0.25 mbar and temperatures up to 493 K. A new type of surface reconstruction was observed that is formed by carbidic carbon, as shown by X-ray photoelectron spectroscopy. Using 13CO and titrating 13C with O2, the surface carbon is shown to originate from CO. The results are in contrast to predictions by theoretical work. However, the dissociation rates are 3 orders of magnitude lower than the previously measured methanation rates under equivalent conditions.