A Scaling Method for Correlating Ex Situ and In Situ Measurements in PEM Fuel Cells and Electrolyzer

Correlating ex-situ measurements of Pt coverage using the thin film-rotating disk electrode (TF-RDE) and in-situ performance of proton exchange membrane (PEM) type fuel cells and electrolyzer is established. The TF-RDE has a smaller geometric electrode area, and, typically, lower Pt loading is used compared to the in-situ single cell of PEMs. The model equation for Pt contamination by adsorption mechanisms followed by dimensionless analysis enables us to find three important dimensionless groups, which has been shown to control the contamination phenomena. The capacity ratio of Pt loading and inlet concentration of the contaminant, the measure of the rate of reaction, and the coverage ratio of the contaminant is used to translate ex-situ to in-situ by providing the scaling factor that is key to the correlation. These scales lead to the prediction of the coverage on the Pt sites using the ex-situ adsorption isotherm. Also, dimensionless numbers are tested in in-situ performance tests of PEM fuel cells for validation. (C) 2018 The Electrochemical Society.