Transients of the open-circuit potential during carbon monoxide interaction with oxygen preliminarily adsorbed on smooth and platinized platinum electrodes

Variations of potential E in time tau, observed during the carbon monoxide interaction with preliminarily-adsorbed oxygen O-ads on smooth and platinized platinum electrodes under open-circuit conditions (supporting electrolyte 0.5 M H2SO4), are measured. The potential decay rate on smooth Pt is more than ten times that on Pt/Pt; there are some differences in the transients as well. The obtained data suggest that CO interacts with O-ads on smooth Pt and Pt/Pt via different mechanisms. Two models for the process on smooth platinum are considered. In one model, the interaction of O-ads with CO from solution is accepted as the rate-determining step; in the other, the interaction of O-ads with COads. A comparison of theoretical E vs. tau dependences with experimental data using the MathCad program suggests that CO interacts with O-ads via both mechanisms.