Catalyst Ink Optimization for Proton Exchange Membrane Water Electrolysis

Hydrogen is a promising clean energy carrier. Proton Exchange Membrane (PEM) water electrolysis offers a pathway for producing clean hydrogen. Water Electrolysis is the process of splitting water molecules into hydrogen and oxygen gas, using renewable electricity. In a PEM electrolyzer, water is pumped into the cell at the anode side. This is where the water molecules are split. The PEM allows only the protons of the hydrogen to pass through to the cathode side, forcing the electrons to travel along an external circuit. The electrons meet the protons at the cathode side, where they recombine and form hydrogen gas. The drivers that make these reactions occur are Platinum Group Metal (PGM) catalyst layers that coat the membrane on both sides. Iridium is used on the anode side for the Oxygen Evolution Reaction (OER) and platinum-on-carbon on the cathode side for the Hydrogen Evolution Reaction (HER). Both metals are expensive, and Iridium is rare and scarce, making large-scale deployment difficult at the current supply and demand levels. This research takes commercially proven catalyst powders and optimizes the mixing and coating process. Catalyst inks were prepared using controlled solvent composition, dispersion conditions, and ionomer content while varying catalyst weight to produce catalyst-coated membranes (CCMs) with different catalyst loadings for electrochemical evaluation in PEM electrolyzers. These CCMs will be used to investigate the relationship between catalyst weight, catalyst loading, and PEM electrolyzer performance, providing insight into catalyst utilization and potential future manufacturing optimization.