In-Situ Measurement of Oxygen Partial Pressure in a Cathode Catalyst Layer

A micro-structured electrode scaffold (IVIES) was developed for performing in-situ measurements of through-plane oxygen partial pressure (OPP) distributions in the cathode of a polymer electrolyte membrane fuel cell (PEMFC). Alternating layers of insulating material and platinum are stacked and bonded, and surround a 100 micron diameter hole filled with catalyst layer material. The platinum layers serve as ultra-microelectrodes, allowing the measurement of local OPP at discrete intervals through the catalyst layer thickness. Following an investigation of ultra-microelectrode sensitivity and repeatability, pulsed amperometric detection was selected over potentiostatic operation as the most effective method for performing OPP measurements. Using calibration points at the full air and zero OPPs, the OPP distribution at a fuel cell current density of 450 mA cm(-2) was measured.