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U.S. Department of Energy
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Cathode catalyst for primary phosphoric acid fuel cells. Fifth quarterly report, July-September 1980

Technical Report ·
OSTI ID:6729428
Alkylation of Vulcan XC-72 has been shown to provide the most stable bond type for linking CoTAA to the surface of the carbon; this result is based on data obtained by cyclic voltammetry, pulse voltammetry and by release of 14C from bonded CoTAA. Half-cell tests at 100/sup 0/C in 85% phosphoric acid have shown that CoTaa bonded to the surface of carbon (Vulcan XC-72) via an alkylation procedure is a more active catalyst than is platinum based on a factor of two improvement in Tafel slope; dimeric CoTAA has catalytic activity equal to platinum. Half-cell tests also have shown that bonded CoTAA catalysts do not suffer a loss in potential when air is used as a fuel rather than oxygen. Commercially available PTFE has been shown to be stable four months in 200/sup 0/C 85% phosphoric acid based on lack of change in surface wetting properties, IR and physical characteristics. When stressed electrochemically in 150/sup 0/C 85% phosphoric acid, PTFE has also shown no changes after one month.
Research Organization:
ECO, Inc., Cambridge, MA (USA)
DOE Contract Number:
AI01-77ET11272
OSTI ID:
6729428
Report Number(s):
DOE/NASA/0150-80/5; NASA-CR-165198
Country of Publication:
United States
Language:
English