Degradation studies of PEMFC cathodes based on different types of carbon

• In this study different accelerated degradation tests were used evaluating three different carbon supports as well as a thin model electrode. Cyclic ADTs, by 1000 cycles beween 0.6 and 1.2 V in nitrogen, did not degrade the porous electrodes to any larger extent in terms of oxygen reduction activity, whereas a significant loss of electrochemical surface area was seen, often more than 50%. Potentiostatic hold at 1.4 V during 3 h, did not permanently degrade the electrodes but instead an improved activity was obtained after rest during night. A correlation of increase in double layer capacitance and improved performance was seen and believed to be caused by the good proton conductivity of carbon surface oxides. CO-stripping peaks revealed that the humidity and wetting of Nafion™ may have caused the observed temporary changes during the potentiostatic hold. ©The Electrochemical Society.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

Accelerated degradation tests

Carbon support

Carbon surface oxides

Degradation study

Double-layer capacitance

Electrochemical surface area

Oxygen Reduction

PEMFC cathode

Porous electrodes

Potentiostatics

Degradation

Electrolytic reduction

Membranes

Oxygen

Proton exchange membrane fuel cells (PEMFC)

Protons

Stripping (dyes)

Electrochemical electrodes

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