Advanced Multimodal X-ray Visualization Techniques for Unraveling Catalytic Performance and Degradation Mechanisms of Metal Nanoparticles in Fuel Cells

Abstract

This Account highlights the transformative advances enabled by the world-first BL36XU beamline dedicated to in situ and operando characterization of metal nanoparticles and adsorbed species in polymer electrolyte fuel cells (PEFCs). While PEFCs hold great promise for sustainable energy conversion, they have not yet reached a level that makes them irreplaceable by alternative energy systems. To address this challenge, we developed complementary multimodal X-ray techniques including time-resolved QXAFS–XRD, HERFD-XANES–RIXS–XRD–QXAFS, same-view nano-XAFS–STEM/EDS, and 3D CT–XAFS, which provided unprecedented insights into critical issues such as spatially non-uniform performance, multi-element degradation mechanisms, and complex distribution–structure–activity–durability relationships of Pt-based electrocatalysts in PEFCs under operating conditions. Future perspectives emphasize simultaneous detection of light and heavy elements by combining hard X-rays with muonic X-rays. The advanced methodologies will drive the rational design of durable, cost-effective PEFCs for heavy-duty vehicles and establish a transferable paradigm for studying other electrochemical and heterogeneous catalytic systems.