A PEM water electrolyser based on metallic iridium electrocatalyst, Pt/C and an Aquivion membrane

An Iridium black nanosized anode electrocatalyst was coupled to an Aquivion short-side chain perfluoro-sulfonic acid membrane (90 µm; EW: 980 g/eq) for operation in a PEM electrolyser. Iridium black powder has been synthesized by chemical reduction of H2IrCl6x6H2O using NaBH4 as chemical reducer according to Ref. [1]. The electrocatalyst has been evaluated in a single cell polymer electrolyte membrane water electrolyser (PEMWEs) of 5 cm2, based on Aquivion® membrane and 30% Pt/C as cathode catalyst [2, 3]. The single cell was investigated by using linear sweep voltammetry, electrochemical impedance spectroscopy and chrono-potentiometric measurements. The electrochemical activity of this MEA was analyzed in a temperature range from 25° to 90°C. The properties of this electrocatalyst have been investigated with the help of both ex-situ characterization and in-situ electrochemical diagnostics.