In-situ 3D CT-XAFS Imaging of Pt/C Cathode Catalysts in Polymer Electrolyte Fuel Cell During Degradation Processes by Anode Gas Exchange Cycles

Polymer electrolyte fuel cell (PEFC) is one of the most efficient clean energy generation systems with high power density at low temperatures, which has a great advantage for its automotive applications. However, a major problem is practically insufficient durability of the membrane electrode assembly (MEA) in PEFC under the operating conditions, especially during startup/shutdown cycles of PEFC, where the feed gases are exchanged. When the anode feed gas exchange cycles are repeated, while keeping the cathode under air, the cathode catalyst degradation proceeds [1, 2]. To visualize 3D degradation of the cathode catalyst layer, we measured the structural and electronic changes of Pt nanoparticles in the PEFC MEA during the anode-gas exchange (AGEX) cycles by in-situ CT-XAFS imaging technique [3, 4] at our beamline BL36XU in SPring-8.