Infrared thermography for mapping catalyst distribution and detecting defects in PEM fuel cell and electrolyzer electrodes

Abstract

Polymer electrolyte membrane fuel cells and electrolyzers require reliable quality control methods to assess catalyst distribution on electrode surfaces. Non-uniform catalyst deposition may reduce performance, increase platinum waste, and promote local degradation. In this work, infrared thermography is proposed as a rapid and automatable method for generating catalyst distribution maps and detecting localized defects in catalyst-coated electrodes. The method exploits the thermal response generated by the localized exothermic reaction between a H 2 /N 2 gas mixture and the Pt-based catalyst layer. A production-line-compatible setup was developed by directing the reactive gas mixture through a metallic nozzle moved by a Cartesian robot. The effects of nozzle diameter, nozzle-to-electrode distance, scanning speed and direction, hydrogen concentration, and total flow rate were investigated to define suitable operating conditions. The selected configuration used a 0.33 mm nozzle, a 3 mm nozzle-to-electrode distance, and a scanning speed of 3000 mm min −1 . A simplified CFD model supported interpretation of the experimental results by correlating temperature increase with gas-jet impact pressure. The optimized procedure enabled thermal mapping of the electrode surface. Catalyst-rich and catalyst-poor regions were identified through local temperature variations, while localized defects appeared as thermal singularities.