Effect of catalyst layer deposition method on the durability and hydrogen isotope separation of PEM electrolyzers

This study systematically investigated the influence of catalyst layer deposition methods on the performance, durability, and hydrogen isotope separation behavior of proton exchange membrane (PEM) water electrolyzers operated at low temperatures (≤40 °C). Four membrane electrode assemblies (MEAs) were fabricated using the catalyst-coated substrate (CCS) and catalyst-coated membrane (CCM) methods for both the anode and cathode. Although the initial performances of the MEAs were comparable, significant differences emerged during 100 h of continuous operation. Catalyst layers prepared using the CCS method exhibited superior water electrolysis performance and more stable hydrogen isotope separation behavior than those prepared using the CCM method. In particular, the anode catalyst layer deposition method had a substantially greater influence on electrochemical durability and isotope separation stability than the cathode deposition method. This systematic comparison of MEA configurations demonstrates the critical role of catalyst layer architecture in maintaining stable low-temperature hydrogen isotope separation in PEM water electrolyzers.