Enabling High-Throughput Catalyst Layer Studies for PEM Water Electrolysis─From Fabrication to Electrochemical Testing

Proton exchange membrane water electrolyzers (PEMWEs) play a key role in the decarbonization of the energy sector. However, due to limited availability and the need to lower the overall costs of PEMWE stacks, reducing iridium loading at the anodic oxygen evolution reaction (OER) side is crucial for this technology to be a game changer in hydrogen production. When the anode is optimized for minimum catalyst loading, several parameters influencing its activity and stability must be considered, including pore size, support material, and the ionomer-to-catalyst (I/C) ratio. Currently, parameter optimization is performed by using several time- and resource-intensive single coating experiments and full cell testing. In this work, we present a high-throughput coating and testing platform for the PEMWE anode catalyst layers. It consists of a tabletop slot die coating setup for graded catalyst coating and a half-side catalyst-coated membrane (CCM) scanning flow cell (SFC) setup coupled with an inductively coupled plasma mass spectrometer (ICP-MS). We present an accelerated catalyst loading study where all samples are produced within a single coating by varying the volume flow into the slot die head. The wet film thickness is controlled inline by a laser profile sensor (LPS), and the loading is determined via X-ray fluorescence (XRF). Subsequently, catalyst OER activity and stability were analyzed using the half-CCM ICP-MS setup. The results show consistency in wet film thickness, loading, catalyst layer activity, and stability. This confirms that with the reported platform, optimization of the catalyst layer parameters can be accelerated to ultimately improve the efficiency and stability of catalyst layers in PEMWE or other energy conversion technologies.