Investigation on the effects of carbon monoxide contamination towards PEMFC transport phenomena using a kinetics-transport bridging model

Abstract

This paper reports a numerical study on the effects of CO contamination towards the distribution of chemical species, surface coverage, current density and temperature inside a PEMFC using a kinetics-transport bridging model. Bridging is done by linking macro-scale, macro-homogeneous transport phenomena models with micro-scale contamination kinetics model via conversion of the surface concentration of the reactants on the rough electrocatalyst into surface site coverage of the participating adsorbates using Langmuir-Freundlich isotherm. The effects of CO contamination is investigated by solving the bridged model iteratively under steady state, single phase and non-isothermal conditions in three-dimensions. The effect of CO-ad presence on the electrocatalyst surface towards distribution of chemical species, current density and temperature is discussed at cell temperature of 70°C and two nominal current densities of 0.5 and 1.0 A/cm 2 . The results show that the region under the ribs at anode catalyst layer registered higher magnitude of current density due to blockage from CO-ad under channel. The anode catalyst layer also shows an increase in local temperature comparable to the cathode catalyst layer that can aggravate dehydration of the membrane, which in turn affect its durability in long-term operation.