Imaging of the Catalyst Layer Structure of Fuel Cells by Atomic Force Microscopy

Abstract

Materials-sensitive atomic force microscopy (AFM) was used to analyze the ionomer distribution in fuel cell catalyst layers close to operation conditions. This method was used here to study and compare catalyst layers made of PFSA- and hydrocarbon-based ionomers. The material contrast between the ionomer and Pt/C catalyst in adhesion force images is selected to visualize the ionomer distribution. The average ionomer layer thickness was analyzed depending on the ionomer loading of the catalyst layer and measurement conditions like elevated temperature and defined relative humidity. The demonstrated approach can play an important role in the design of advanced catalyst layers for PEMFC application.