Mobility on the reconstructed Pt(100)-hex surface in ethylene and in its mixture with hydrogen and carbon monoxide.

By using high-pressure scanning tunneling microscopy and ambient-pressure X-ray photoelectron spectroscopy, we studied the mobility along with composition, structure and reactivity on the Pt(100)-hex surface. Adsorbates are mobile under 1 Torr of C2H4 and C2H4-H2 mixtures, but adding 3 mTorr of CO quenches the mobility. Ethylene-related adsorbates can also weaken Pt-Pt bonds and thus facilitate displacements in the hexagonal layer.