IN-SITU SCANNING-TUNNELING-MICROSCOPY STUDY OF PLATINUM (110) IN A REACTOR CELL AT HIGH-PRESSURES AND TEMPERATURES

With a specialized version of a scanning tunneling microscope which allows us to study in situ the atomic structure of surfaces under variable pressures (ultrahigh vacuum-atmospheric) and temperatures (300-425 K), we have investigated the structures of the initially clean (110) surface of single crystal platinum while in environments of hydrogen, oxygen, and carbon monoxide. The surface in 1.6 atm of hydrogen appears to be dominated by various sizes of nested missing-row reconstructions. The surface in 1 atm of carbon monoxide, however, does not have the small scale,missing-row reconstructions, but does appear to have flat terraces separated by multiple height steps. The surface in 1 atm of oxygen appears to have enlarged (111) microfacets.