Oxygen reduction reaction, polarization behavior

In analyzing the polarization data, it can be seen that the cathodic reaction on the copper (oxygen reduction) quickly becomes diffusion controlled. However, at potentials below -0.4 V, hydrogen evolution begins to become the dominant reaction, as seen by the Tafel behavior at those potentials. At the higher anodic potentials applied to the steel specimen, the effect of uncompensated ohmic resistance (IRohmk) can be seen as a curving up of the anodic portion of the curve. 

Reduction to Alcohols. The organosilane-mediated reduction of ketones to secondary alcohols has been shown to occur under a wide variety of conditions. Only those reactions that are of high yield and of a more practical nature are mentioned here. As with aldehydes, ketones do not normally react spontaneously with organosilicon hydrides to form alcohols. The exceptional behavior of some organocobalt cluster complex carbonyl compounds was noted previously. Introduction of acids or other electrophilic species that are capable of coordination with the carbonyl oxygen enables reduction to occur by transfer of silyl hydride to the polarized carbonyl carbon (Eq. 2). This permits facile, chemoselective reduction of many ketones to alcohols. 

This is the general behavior that may be expected whenever there are two possible reactions in a given potential range. Most of the time in metal electrodeposition, these two reactions are the reduction of metal cations and the discharge of hydrogen ions, but other cathodic processes are also possible, e.g., the discharge of dissolved oxygen. A similar behavior is to be expected in the electrodeposition of binary alloys when the difference between the equilibrium potential of the two metal redox couples is remarkable. The typical shape of the polarization curve as briefly discussed... 

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