Thin-film model charged species

In the active parts of a gas diffusion electrode, the pore electrolyte is contained in the small pores between the catalyst particles and the carbon support particles. The larger pores are then filled with gas. Gas has to diffuse through a thin film of electrolyte and in the small pores that contain the pore electrolyte. This introduces an additional mass transfer resistance that can be described with an agglomerate model. Such a model is described with a diffusion-reaction equation for the gaseous species dissolved in the pore electrolyte with the charge transfer reactions as source or sink. The solution to this reaction diffusion model is used to calculate new reaction terms that replace the reaction terms in the balance of charge, material, mass, and energy. These models can often be solved analytically for steady-state if the reactions are of... 

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