I am studying an electroactive species that adsorbs on the electrode and seems to block the electrochemical active sites for the ferro/ferri system, as shown by some CV tests. However, when I do the CV to check the controlling process for the oxidation of this species, the graph of log(peak current) vs. log(scan rate) shows a slope that demonstrates diffusion control at peak current. I have several questions:

1. Do you think this species adsorbs significantly on the electrode as adsorbate but its oxidation is diffusion controlled? So there is not necessarily a relationship between this adsorption and the controlling process at the electrochemical interface?

2. What alternative method do you recommend to verify the control in the voltammograms other than the CV method?