Development of an ultra-thin electrode for the oxygen evolution reaction in proton exchange membrane water electrolyzers

Noble metal electrocatalysts are highly preferred for the oxygen evolution reaction (OER) in a proton exchange membrane water electrolysis cell (PEMWE) due to their exceptional catalytic activity and stability. This study proposes a novel thin electrode (NTE) design to enhance the performance of noble metal electrocatalysts for the OER in PEMWE. The NTE utilizes a thin porous transport layer for the direct deposition of Iridium (Ir). Unlike conventional gas diffusion electrodes with deep porous structures that underutilize the catalyst due to limited triple-phase boundary conditions, the flat NTEs with straight-through pores overcome this restriction. The paper compares two deposition methods, electroplating and sputter coating. The in-situ electrochemical properties of NTEs with varying Ir loadings (0.06–1.01 mg cm−2) are investigated. The electroplated NTE demonstrates excellent mass activity, achieving 5.05 A mg−1 at 1.6 V and 80 °C. The NTE exhibits a simple fabrication process and low cost while significantly improving catalyst mass activity. Additionally, the NTE reduces electrode thickness from hundreds of micrometers to only 25 μm. This concept holds great promise for the future advancement of compact and high-efficiency PEMWE electrodes, resulting in reduced cost, volume, and mass of both the electrode itself and the overall system.