Elemental Distribution in Catalyst-Coated Membranes of Proton Exchange Membrane Water Electrolysers Tracked by Synchrotron X-Ray Fluorescence

Abstract

The stability of catalyst layers and membranes in proton exchange membrane water electrolysis (PEMWE) cells represents an ongoing challenge, compounded by the dissolution of components and migration of elements within the catalyst-coated membrane (CCM). Conventional microscopy methods often struggle to efficiently evaluate large cross-sections of PEMWE membranes, which is essential for representative analysis of technical scale CCMs. Herein, synchrotron radiation-based X-Ray fluorescence microscopy is exploited to analyze the stability of CCMs with around 1 μm resolution and a field of view of ≈200 × 75 μm². Three application scenarios are investigated: 1) migration of catalyst elements, 2) dissolution of components, and 3) contaminated water supply containing ${\text{Fe}}^{2+}$ ions. XRF is performed at three different X-Ray energies (11.7, 11.4, and 11.0 keV), revealing the local elemental composition, including Pt, Ir, Ti, and Fe, under different stressing conditions. Notable observations include the distribution of Ir across the membrane and in the cathode catalyst layer, localization of Pt within the membrane, accumulation of Ti in the cathode catalyst layer, and minimal presence of Fe. XRF has been demonstrated to be a powerful analytical tool for accurate and high throughput imaging of catalyst degradation in PEMWE scenarios, particularly of technical scale devices.