O2 reduction on the Pt/polymerelectrolyte interface
The oxygen reduction/evolution reaction
Published Online: 15 DEC 2010
Copyright © John Wiley & Sons, Ltd. All rights reserved.
Handbook of Fuel Cells
How to Cite
Ota, K. and Mitsushima, S. 2010. O2 reduction on the Pt/polymerelectrolyte interface. Handbook of Fuel Cells. .
- Published Online: 15 DEC 2010
In order to attain the high performance of polymer electrolyte fuel cells (PEFCs), the cathode overpotential as well as the resistance of the membrane electrolyte should be reduced. In this paper, the oxygen reduction reaction on Pt has introduced in relation to the quality of the polymer electrolyte. The oxygen overpotential was measured by three electrodes using the mini-cell method. The mini-cell has a Pt microelectrode for the working electrode and a dynamic hydrogen electrode for the reference electrode. The contact force at the Pt electrode/membrane interface was measured and controlled by a strain gauge. The solubility and the diffusion coefficient of oxygen in the polymer electrolyte depended on the ion-exchange capacity of the membrane electrolyte. The diffusion coefficient increased with the decrease of the ion-exchange capacity. The solubility increased with the increase of the capacity. The dependence of the diffusion coefficient was larger than that of the solubility. The Tafel plot of oxygen reduction current on the Pt showed the two distinct mechanisms for the low and the high overpotential regions. At the low overpotential region, the oxygen reduction reaction proceeded by a 4–electron reaction, the exchange current density had a range from 10−9 to 10−8 A cm−2. The dependence of the exchange current density on the ion-exchange capacity was small.
- polymer electrolyte fuel cell (PEFC);
- oxygen electrode;
- polymer electrolytes;
- reaction mechanisms in electrochemistry;
- oxygen electrode;
- current-potential characteristics;
- solid-polymer electrolytes;
- cyclic voltammetry;
- electrode-micro- and ultra-micro;
- exchange current density;
- numerical values;
- solid polymer electrolyte;
- ion exchange capacity