(Electro)chemical and Mechanical Degradation Studies of Commercial Proton Exchange Membranes in HCl/Cl ₂ Systems for Hydrogen/Chlorine Production

electrolysis conditions. Characterization techniques included contact angle measurements, tensile strength testing, thickness analysis, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR-ATR), and long-term electrolysis testing. While Nafion membranes demonstrated good mechanical strength, they showed notable surface degradation and chemical instability under acidic conditions. In contrast, Aquivion E98-09S exhibited superior chemical resilience and structural integrity, even after 300 h of continuous operation in 20 wt% HCl. These findings underscore the importance of tailored membrane selection for chlorine-rich electrochemical systems and offer valuable insights for the development of more robust and durable PEM materials for halogen-based electrolysis technologies.