Proton exchange membrane water electrolysis with short-side-chain Aquivion® membrane and IrO2 anode catalyst

Abstract

A series of three membrane types has been screened for medium temperature solid polymer electrolyte water electrolysis in membrane electrode assemblies coated with 2 mg cm-2 of iridium oxide as a catalyst for the oxygen evolution reaction, synthesised via a hydrolysis method from the hexachloroiridic acid precursor, and deposited on the membrane either directly by spray deposition or by decal transfer. The short-side-chain perfluorosulfonic acid Aquivion® ionomer of equivalent weight 870 meq g -1, in membranes of thickness 120 μm, gives higher water electrolysis performance at 120 °C than a composite membrane of Aquivion® with zirconium phosphate, while a sulfonated ether-linked polybenzimidazole, sulfonated poly-[(1-(4,4′-diphenylether)- 5-oxybenzimidazole)-benzimidazole], shows promising performance and no transport limitations up to 2 A cm-2. The lowest cell voltage was observed at 120 °C for an MEA prepared using spray-coating directly on the Aquivion ® membrane, 1.57 V at 1 A cm-2. Copyright © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.