Sputtered Low-Loading Ru-Based Porous Transport Electrodes for the Anode Catalyst in Proton Exchange Membrane Water Electrolysis

This study explores magnetron sputtering as a fabrication method for low-loading ruthenium-based anode catalysts for the oxygen evolution reaction in PEM water electrolysis. In addition to demonstrating the advantages of this fabrication method, it is shown how different sputtering parameters influence the obtained catalyst layers. The most promising catalyst layers were deposited on porous transport layers and integrated into membrane electrodes assemblies to perform single cell tests. The Ru-based anodes were combined with equally sputtered Pt-based cathodes for the hydrogen evolution reaction, giving rise to an all-sputtered MEA architecture with no ionomer present in the electrodes. This configuration yielded noteworthy performance and stability under specific testing conditions. Degradation phenomena during durability tests were analyzed via galvanostatic impedance spectroscopy as well as post-mortem characterizations.