Electrochemical reaction engineering of polymer electrolyte fuel cell

Abstract

Although fuel cells can be considered as a type of reactor, methods of kinetic analysis and reactor modeling from the viewpoint of chemical reaction engineering have not yet been established. The rate of an electrochemical reaction is a function of concentration, temperature, and interfacial potential difference (or electromotive force). This study examined the cathode reaction in a polymer electrolyte fuel cell, in which oxygen and protons react over platinum in the catalyst layer (CL). The effects of the oxygen partial pressure and the cathode electromotive force on the reaction rate were assessed. Resistance to proton transport increases the electromotive force and reducing the reaction rate. It was established that the effectiveness factor of the cathode CL is determined by competition between the reaction and mass transport of oxygen and protons. Two dimensionless moduli that govern the cathode behavior are proposed as a means of depicting the processes in the cell.