Preparation of membrane-electrode assemblies
Acid membrane water electrolyzers

Before depositing catalysts on the surface of perfluorosulfonated membranes, they must be cleaned and swollen by immersion in boiling water.

Since the roughness factor of an electrode is a key factor in reducing overvoltage, it can be increased by modifying the surface structure of the membrane. For example, surface abrasion by radio-frequency ion bombardment leads to the formation of polymer "strips", thus increasing the ratio of real area to geometric area through a slight depth effect.

This generally leads to an increase in the roughness factor of around 30%, but the benefit is reduced by the additional cost of the treatment and the increase in gas permeation associated with the reduction...