Impact of iron and hydrogen peroxide on membrane degradation for polymer electrolyte membrane water electrolysis: Computational and experimental investigation on fluoride emission

Polymer electrolyte membrane (PEM) degradation in electrolysis mode is simulated through a Fenton model that includes all major involved electrochemical reactions. Supportive experimental investigations on the effect of hydrogen peroxide and iron impurities are carried out in an ex-situ set-up, where the results are utilized to fit model parameters. The experiments reveal a high dependence of fluoride emission on iron concentration, which catalyzes the reaction, and identifies hydrogen peroxide as a necessary precursor for destructive hydroxyl radical formation. Simulations of in-situ operation reveal that elevated current is favorable in terms of lower fluoride emission, as the radicals are depleted by side reactions. Temperatures above 80∘C significantly accelerate membrane thinning, where the step from 80∘C to 90∘C more than doubles thinning after 500 h.