Oxygen reduction and transport characteristics at a platinum /sulfonated poly ether sulfone membrane interface

Abstract

Kinetic and mass transport properties were investigated for the oxygen reduction reaction in Nation® 117 and a sulfonated poly (arylene ether sulfone) membrane (SPES-40) at 100% relative humidity (RH) as a function of pressure and temperature using a solid-state electrochemical cell. Kinetic parameters were obtained using slow-sweep voltammetry while mass transport parameters, the diffusion coefficient (D) and solubility (C), were obtained using chronoamperometry at a Pt/proton exchange membrane (PEM) interface. Oxygen reduction kinetics was found to be similar for both Nafion® 117 and SPES-40 membrane at the Pt microelectrode (100 μm) interface. The temperature dependence of O 2 permeation parameters showed similar trends for both the membranes while the pressure dependence of O 2 permeation parameters showed major differences. Despite lower equivalent weight and hence higher water content SPES-40 exhibited relatively lower values of D with Nafion® 117. The results are discussed in the context of their different microstructures.