Structural effects induced by CO adsorption on Pt-bimetallic surfaces

Synchrotron surface X-ray scattering (SXS) studies have been performed duri ng the coadsorption of metal adatoms and carbon monoxide on single crystal Pt surfaces in an electrochemical environment. As the applied electrode pot ential is the driving force behind adsorption, the electrochemical system i s in chemical equilibrium, which results in a range of structural phenomena , such as mixing, segregation, compression and displacement. The mechanisms behind these effects are studied by monitoring the diffraction signals fro m ordered adsorbed metal and CO adlayers that occur on the Pt(111) and Pt(1 00) surfaces.