Cathode contamination experimental

The cathode contaminants sources and general mechanisms are described in chapter 2, and a more detailed discussion on mechanisms, experimental results, and mitigation is provided in chapter 3. 

Contamination modeling is an important aspect of fuel cell development. It is required to interpolate and extrapolate experimental results to expected conditions in real-world operation, as it is impractical to test all combinations of reactant concentrations and fuel cell operating conditions. Modeling also assists in the development and validation of hypothesized contamination mechanisms. Model development for the anode is more extensive than that for the cathode contamination. The majority of the modeling deals with the kinetic effects associated with adsorption of contaminant species on the cathode and anode catalysts. 

Figure 8. Diagram of an experimental setup for laboratory studies of electro-osmotic flushing technique to remove heavy metals from clays. It is basically an electro-osmotic dewatering setup with the addition of a continuous flow of purge solution at the anode and removal of contaminated water at the cathode.

When contaminant presents in the fuel cell, its concentration at the catalyst layer varies with both the inlet contaminant concentration and the current density, as discussed in Shi et al. [18]. Furthermore, the contaminant adsorption (desorption) rate constant is also related to the electrode potential. This variation of the contaminant concentration can be obtained by introducing the CGDL and cathode flow field into the model, which definitely increases its complexity. For simplicity here, we considered the product of the contaminant adsorption (desorption) rate constant and the contaminant concentration at the CCL, as a fimction of current density and contaminant inlet concentration (kCp-- f Cpr J))/ where Cp is the contaminant inlet concentration in the cathode charmel. Based on the experimental data at current densities of 0.2, 0.5, 0.75, and 1 A/cnP, and contaminant inlet concentrations of... 

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