Scalable Catalyst Coated Membranes in the Low μg Ir /cm 2 Range for Proton Exchange Membrane Water Electrolysis Facilitated by Antimony-Doped Tin Oxide Nanofibers

High Resolution Image Download MS PowerPoint Slide Lowering the iridium content in the anodic catalyst layer remains one of the main challenges for proton exchange membrane water electrolysis (PEM-WE), as it can cause discontinuous catalyst layers and increased overpotentials. In this work, we managed to reproducibly cast anodic catalyst layers with a loading as low as 22 μg Ir /cm 2 by introducing electrospun antimony-doped tin oxide (ATO) nanofibers along the IrOx nanoparticles. In addition to a facilitated fabrication route for low-loaded catalyst layers via casting, electrolyzer cells with these ATO-supported catalyst layers reached a loading-normalized current of 454 A/mg Ir at their maximum operating point, which is almost four times higher than the reference cells (120 A/mg Ir ) with a loading of 100 μg Ir /cm 2 .