A comparison of several models for porous gas-diffusion electrodes

Abstract

Four different models for the analysis of porous gas-diffusion electrodes are described, and the resulting current density-polarization characteristics compared. A generalized system consisting of both gas and liquid phase reactants in the presence of inert components is considered. The models differ in the assumed nature and degree of coupling between the diffusion and reaction mechanisms, as well as the basis for determining the distribution of the gas-liquid interface within the pore structure of the electrode. For a given generalized reaction mechanism, the resulting slopes and intercepts of the linear region of the various polarization curves, as well as limiting currents, are shown to depend upon the assumed degree of coupling between diffusion and reaction mechanisms. In addition, one model shows a dependence of these polarization characteristics upon operating pressure differentials in conjunction with pore characteristics.