Electrochemical oxidation of carbon monoxide: from platinum single crystals to low temperature fuel cells catalysts. Part I: Carbon monoxide oxidation onto low index platinum single crystals

The electrochemical oxidation of carbon monoxide and the interfacial structure of the CO adlayer (COads) on platinum low index single crystals, Pt(111), Pt(100) and two reconstruction of Pt(110), were examined using the rotation disk electrode method in combination with the in situ surface X-ray diffraction scattering technique. The mechanism of CO oxidation is discussed on the basis of the findings that, depending on the potential, two energetic states of COads exist on the platinum surfaces. Thus, at lower potentials, weakly bonded states (COads,w) and at higher potentials strongly bonded states (COads,s) are formed. The mechanism of the oxidation of hydrogen-carbon monoxide mixtures is also proposed.