A broad scientific consensus exists that anthropogenic emissions are major factors fueling global warming and its potential impacts on the earth’s ecosystem. On the way to a sustainable and decarbonized energy supply, "green" hydrogen is an emission-free alternative to conventional energy carriers. In this context, proton exchange membrane fuel cells (PEMFCs) offer promising properties for the electromobility by a simple scalability of the performance through the modular design of fuel cell stacks, a refueling time and range comparable with conventional combustion engines and zero emissions if "green" hydrogen is used. Despite all scientific work on this field – performance, cost and durability issues still hamper the wide commercialization of PEMFCs.Concerning the durability, global fuel starvation causes destructive and irreversible degradation at the anode catalyst. A lack of fuel supply leads to the anode potential being raised to levels where the oxygen evolution reaction (OER) and carbon oxidation reaction (COR) take place instead of the hydrogen oxidation reaction (HOR). Thus, the overall cell voltage reverses compared to normal operation. In consequence, the widely employed carbon-supported anode catalyst corrodes and the overall cell performance is reduced if appropriate mitigation strategies are absent [1]. Among other remedies, incorporating a second catalyst component with an enhanced OER activity, such as IrO2 [2], is a promising material-specific strategy. Within this study we present a technical approach on single cell level (50 cm2 geo) to investigate and evaluate the impact of short-pulsed versus long-lasting fuel starvation events on the degradation of a reversal-tolerant anode catalyst layer comprising Pt/C and IrO2 [3]. By utilizing an on-line mass spectrometer, the anode exhaust gas stream is examined in terms of O2- and CO2-amounts to reveal the origin of the degrading effect.