STXM Study of the Ionomer Distribution in the PEM Fuel Cell Catalyst Layers

A method of imaging ionomer in the catalyst layer (CL) of the catalyst coated membrane (CCM) in the proton exchange membrane (PEM) fuel cell was developed using scanning transmission X-ray microscopy (STXM). Component maps for ionomer in CL relative to the catalyst/carbon-support were obtained from STXM images at a few specifically pre-defined energies in the C 1s (on/off a peak characteristic for carbon support in the catalyst layer) and F 1s …