A Study of the Degradation of Platinum Black Fuel Cell Cathodes.
Interim technical rept. no. 1,
TYCO LABS INC WALTHAM MASS
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The report deals with a study of the mode of cathode electrocatalyst degradation in the H2-air phosphoric acid matrix fuel cell. BET, X-ray line broadening, and pore-size distribution techniques have been used to determine the degree of catalyst recrystallization. Sintering of dry platinum black in air at 100 - 150C leads to an initial rapid loss of surface area within twenty-four hours, followed by a more gradual decrease to 43 plus or minus 2 of the original surface area after 500 hours independent of temperature. X-ray line broadening. however, shows no observable increase in average particle size corresponding to this surface area decrease. This indicates that the loss of surface area may be the result of a coalescence of crystallites with no effective change in average grain size. Sintering of dry Teflon-bonded platinum black electrode material in air was also conducted. Preliminary results of electrochemical testing in an 85 phosphoric acid electrolyte at these elevated temperatures have indicated that there may be an effect of electrolyte on the observed surface area decreases. Author
- Physical Chemistry
- Electric Power Production and Distribution