Oxygen reductive potentials

Figure 16.8 Pt/TiO c-catalyzed oxygen reduction potential, where 0.01 mA cm is reached during the negative scan in a cyclic voltammetry experiment (scan rate 20 mV s ) in oxygen-saturated 0.5 M HCIO4 at 25 °C. (See color insert.)...

The discharge curve for Air electrode, which was measured using additional third Ag AgCl reference electrode, is ideally horizontal since it is determined by the oxygen reduction potential in according medium... 

Specific energy, which could be attained as primary battery is of about 140 W-h/kg for Air/PANI-Zn and 200 W-h/kg for Air/PANI-Mg batteries. The discharge curves of such batteries is practically horizontal since there are determined by the oxygen reduction potential. 

Extrapolation of the linear portion of the curves to the standard oxygen reduction potential gives the corresponding exchange current density, a measure of the equilibrium rate of the reaction [35]. The results are given in Table I. Within... 

In acetonitrile, the valence band of Ti02 lies at about +2.4 V versus the standard calomel electrode and the conduction band lies at -0.8 V. The hole migrates to the surface where it oxidizes adsorbed olefin (oxidation potential = +1.4 V), producing a surface-bound cation radical. The electron also migrates to the surface where it is captured by adsorbed oxygen (reduction potential = -0.75 V), forming adsorbed superoxide. 

Little et al [1] have pointed out that ennoblement in fresh and brackish water is related to the microbial deposition of manganese whereas in seawater, this phenomenon may be ascribed to depolarisation of the oxygen reduction reaction that may occur, in effect, due to some of the proposed mechanisms mentioned above such as mechanisms 1,2, and 4. For example, it is well known that the oxygen reduction potential shifts positive (about 60 mV) for each decrease in pH unit and such a decrease produces a noble shift of 35 to 40 mV on stainless steel electrodes in seawater [41, 43], see also [6, 7]. Figure 4.5 shows how the increase in potential due to biofilm formation can endanger the material to pitting. 

In 2005, Cui and co-workers studied the electrocatalytic oxygen reduction reaction by electrodepositing Pt nanoparticles on MWNTs. A significant positive shift in oxygen reduction potential and a concurrent increase in oxygen reduction current have been observed. Pt nanopartides deposited on MWNTs also exhibited enhanced transfer rates of dectrons as wdl as stability for methanol oxidation. ... 

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