Spatially Resolved Characterization of Catalyst-Coated Membranes by Distance-Controlled Scanning Mass Spectrometry Utilizing Catalytic Methanol Oxidation as Gas--Solid Probe Reaction

摘要

The spatially resolved catalytic activity of a catalyst-coatedmembrane (CCM), which is the essential part of PEM fuel cells, was visualized rapidly without any damage by a distance-controlled scanning mass spectrometer with an improved resolution of 250 (mu)m. Methanol oxidation was identified as a suitable gas-solid probe reaction for the characterization of local catalytic activity. In addition, defects were manually generated in the CCM to simulate inhomogeneous coating and pinholes. The measurements successfully demonstrated that catalytically active and less active regions can be clearly distinguished. Simultaneously, the local topography was recorded, providing additional information on the location of the scratches and pinholes. The catalytic results were highly reproducible due to the constant-distance feedback loop rendering scanning mass spectrometry a promising tool for the quantitative quality control of CCMs.