A transient PEMFC model with CO poisoning and mitigation by O2 bleeding and Ru-containing catalyst

In this paper we present a transient, fully two-phase, non-isothermal model of carbon monoxide poisoning and oxygen bleeding in the membraneelectrode assembly of a polymer electrolyte fuel cell. The model includes a detailed description of mass, heat and charge transport, chemisorption,electrochemical oxidation and heterogeneous catalysis (when oxygen is introduced). Example simulation results demonstrate the ability of themodel to qualitatively capture the fundamental features of the poisoning process and the extent of poisoning with respect to channel temperatureand concentration. Further examples show how the multi-step kinetics can interact with other physical phenomena such as liquid-water flooding,particularly in the anode. Carbon monoxide pulsing is simulated to demonstrate that the complicated reaction kinetics of oxygen bleeding canbe captured and even predicted. It is shown that variations in the channel temperature have a convoluted effect on bleeding, and that trends inperformance on relatively short time scales can be the precise opposite of the trends observed at steady state. We incorporate a bi-functionalmechanism for carbon monoxide oxidation on platinum–ruthenium catalysts, demonstrating the marked reduction in the extent of poisoning, theeffect of variations in the platinum–ruthenium ratio and the influence of temperature. Finally, we discuss the implications of the results, extensionsto the model and possible avenues for experimental work