Ethylene adsorption and oxidation on Pt(h k l) in acidic media

Ethylene adsorption and oxidation on platinum electrodes have been investigated in acidic solution by means of cyclic voltammetry and in situ infrared spectroscopy. Ethylene oxidation is a surface structure-sensitive reaction being Pt(1 1 1) the only active electrode surface at potentials below surface oxidation. In situ infrared reflection absorption spectroscopy (IRRAS) allows to identify the products formed during the adsorption and oxidation of ethylene. Vinylidene species were detected as oxidized adsorbates coming from ethylene and the only oxygen-containing species observed were on-top adsorbed CO and dissolved CO2 that is the final oxidation product. A potential dependent equilibrium for transformation between two different adsorption configurations of adsorbed vinylidene, μ3-η2-CCH2 and μ-CCH2, has been observed.