Degradation testing carbon support corrosion

During dynamic tests with thermal, load, and shutdown-start-up cycling, the amount and the vapor pressure of the water product varies and formation of liquid water might be involved. In addition, the shutdown-start-up or/and temperature cycling cause thermal and mechanical stresses to the membranes and cell components as well as volume expansions and contractions of the acid in the MEAs. Another important mechanism of the cell degradation involved in these dynamic tests is the corrosion of carbon supports and growth of noble metal catalysts [10]. Some dynamic test results are summarized in Table 22.10. 

To test the degradation of fuel cell catalyst and assess the carbon support degradation effect on fuel cell performance, many diagnostic tools are available. These tools may test the morphology of the catalyst support directly or may evaluate the carbon corrosion indirectly through the fuel cell overall performance. Common parameters analyzed to evaluate the electrocatalyst degradation include measurement of the catalyst layer areas (cross-sectional and smface area), the ECSA, fuel cell current density, surface morphology, and elemental composition of material or effluent gas. 

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