Cathode catalysts for primary phosphoric-acid fuel cells. Final report

Technical Report · Tue Dec 01 04:00:00 EST 1981

OSTI ID:5270196

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 unstable in the fuel cell environment with degradation occurring in 2000 hours or less. PTFE was stressed at 200/sup 0/C in concentrated phosphoric acid as well as electrochemically stressed in 150/sup 0/C concentrated phosphoric acid; the surface chemistry of PTFE was observed to change significantly as measured by goniometry and by an ESCA technique. Radiolabeled PTFE was prepared and used to verify that such chemical changes also occur in the primary fuel cell environment.

• Research Organization: ECO, Inc., Cambridge, MA (USA)
• DOE Contract Number: AI01-80ET17088
• OSTI ID: 5270196
• Report Number(s): DOE/NASA-150-81/7; NASA-CR-165578; ON: DE82009718
• Country of Publication: United States
• Language: English

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CARBON 14 COMPOUNDS
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CATALYSTS
CATALYTIC EFFECTS
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