Effect of CO impurity in H₂ on the performance of Ni/PTFE diffusion electrodes in alkaline fuel cells

The deactivation behavior of Ni/PTFE electrodes operating with hydrogen gas containing CO impurity was studied in half-cell experiments under potentiostatic conditions. The decay of electrode current densities with respect to time was measured. It was observed that, under the experimental conditions studied, the electrode was deactivated and the electrode current densities reached lower steady-state values upon being subjected to CO impurity in the hydrogen stream. The recovery, which was only partial under all conditions except at 72°C, upon removal of the contaminant CO impurity is also recorded. A total of 12 runs were carried out at three different temperatures. The effect of the concentration of CO impurity was investigated at each temperature. The effect of electrode overpotential was investigated only at 25°C. Also, the effect of electrolyte concentration was studied at 52°C.