Carbon corrosion occurring on the cathode of a polymer electrolyte membrane fuel cell (PEMFC) leads to a reduction in the electrochemical surface area (ECSA). The ECSA is crucial for the efficiency and maximum power output of the fuel cell. Degradation of this component is detrimental to the overall performance of the system. Research into the mechanisms of ECSA degradation is essential for understanding and preventing fuel cell deterioration. The carbon in the electrode functions as a support material for the catalyst and provides the necessary electrical conductivity. Carbon corrosion can increase resistance between the electrode and the catalyst, and research suggests it may even cause the catalyst to detach from the electrode. This thesis investigates carbon dioxide emissions from a PEMFC during an accelerated stress test (AST), measured using a gas analyzer. The exhaust gases contain
approximately 600 parts per million (ppm) of carbon dioxide, fluctuating by about 100 ppm throughout the day. A fluctuation of 80 ppm, attributed to changes in oxygen content during the operational and shutdown phases of the PEMFC stress cycle, was also identified. A formula was applied to remove these fluctuations to better understand the emissions. Carbon dioxide emissions were detected during the startup phase, when a hydrogen-air front is active at the anode, making carbon corrosion at the cathode likely. The area under the emission peak was determined and multiplied by the flow rate, providing an estimate of the carbon dioxide emissions and the corresponding carbon mass loss from the cathode. A secondary objective of this thesis was to validate a mathematical model of carbon corrosion with the obtained data. However, this was not possible with the current data set. The model does
not account for the dynamic conditions of the stress test, which are typically significant contributors to carbon corrosion in a PEMFC.