Cryo-imaging lifts the lid on fuel cell catalyst layers

Thanks to a novel combination of cryogenic transmission electron tomography and deep learning, researchers have provided a first look at the nanostructure of platinum catalyst layers, revealing how they could be optimized for fuel cell efficiency. Proton-exchange membrane fuel cells (PEMFC), which are being developed for use in electric vehicles, rely on nanoparticles called catalysts to trigger electricity-producing reactions between hydrogen and oxygen. Most PEMFC catalysts contain platinum - a scarce and precious metal. There is therefore a pressing global need to develop catalysts that can generate the most power while minimizing platinum content. Manufacturers integrate these catalysts in complex assemblies called catalyst layers. Until now, they had to do so without a detailed picture of the resulting structure, as traditional imaging processes almost always cause some degree of damage. Vasiliki Tileli, head of the Laboratory for in-situ nanomaterials characterization with electrons in the School of Engineering, has found a way around this challenge.