Complex kinetic behaviour of “reduced” CO2 electro-oxidation at Pt electrodes

The electro-oxidation of “reduced” CO2 intermediate adsorbed at different adsorption times and potentials was studied by means of potentiodynamic oxidation profiles and current transients at constant potential. At potentials >0.75 V a Langmuir isotherm is obeyed, while a ·er isotherm is found at potentials <0.75 V. The kinetic behaviour of (CO2)r electro-oxidation can be explained through the existence of two intermediate species of similar chemical composition but different energy content. These species are related through an exchange equilibrium, assisted by the catalyst surface.

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