CVs of the FAO on Pt/GC electrode recorded for the successive increases of the forward potential scan limit are shown in Figure 4.
Extension of the forward potential scan limit slightly influences the reaction currents in the forward scan, while the currents recorded in the backward direction become higher and the peak is shifted to amore negative potential.
The polarization curves for FAO obtained for successive increases of the forward potential scan limit from 0.4 V up to 1.2 V on electrodeposited bimetallic Pt(Bi)/GC surface (Figure 5) indicates quite different behavior in comparison to Pt/GC.
So, for the forward potential scan limit 0.4 V, enhanced adsorption of OH species participates in the oxidation of C[O.sub.ad] species, suggesting an absence of surface poisoning.
Successive increase of the forward potential scan limit in base voltammograms of Pt(Bi)/GC and Pt/GC electrodes is expressed through the dependency of the charge associated with anodic film formation from the electrode potential.
Caption: FIGURE 1: CVs on Pt/C (a) and Pt(Bi)/GC (b) electrodes in 0.1 M [H.sub.2]S[O.sub.4] at 50 mV [s.sup.-1] and [omega] = 1500 rpm for successive increases of the forward potential scan limit.
Caption: FIGURE 2: Oxide formation charge as a function of the forward potential scan limit (data obtained from Figure 1).