Contaminants may be present in amounts that could affect the performance and life-time of fuel cells. The effect of sulphur dioxide and of ammonia in the cathode feed have been studied. Using non-humidified air contaminated with ppm levels of the substances the performance of small scale SPFC cells were recorded. The effect of sulphur dioxide is much more severe than the effect of NH3. The addition of 5 ppm SO 2 leads to a complete loss in cell performance.
Additional exposures are partly reversible.
All effects are ascribed to adsorption of the contaminants on the platinum surface, leading to a decrease in platinum sites which are available for oxygen reduction.