Micro-protective layer for lifetime extension of solid polymer electrolyte water electrolysis

This study uses the reverse electrochemical reaction of Proton Exchange Membrane (PEM) fuel cells, called PEM water electrolysis to produce high concentration hydrogen and oxygen (both 99.99%). The proposed technique can decrease carbon dioxide (CO2) emissions. However, the oxidation and corrosion of the catalysts and gas diffusion layer (GDL) of the anode side remain challenging problems. The carbon fiber is used as the gas diffusion layer for PEM water electrolysis owing to its low density and porosity as well as its good conductivity even under low compression. Noble metal catalysts are coated with a micro-protective layer (MPL) on one side of the gas diffusion layer to extend the lifetime of PEM water electrolysis. The lifetime can reach over 2000 h at high current density (1400 mA cm−2) that is ten times longer than that of a sample coated only with carbon black (XC-72) as the microporous layer. The proposed micro-protective layer can transform active oxygen species to harmless oxygen gas and increase the catalyst's resistance to corrosion and oxidation during water electrolysis.

► Noble metal catalysts with a micro-protective layer on the gas diffusion layer extend the lifetime of catalyst.
► The lifetime of water electrolysis with MPL is more than 2000 h at high current density, 1400 mA cm−2.
► MPL on the gas diffusion layer enhances the resistance to corrosion and oxidation.