PERFORMANCE OF AN IrRu-OXIDE ANODE ELECTROCATALYST AND A SHORT-SIDE CHAIN AQUIVION MEMBRANE IN A PEM WATER ELECTROLYSER

An Ir0.7Ru0.3Ox nanosized anode electrocatalyst was coupled to an Aquivion short-side chain perfluoro-sulfonic acid membrane (120 µm; EW: 870 g/eq) for operation in a PEM electrolyser. A conventional carbon supported Pt catalyst was used as cathode. An excellent performance, of 4 A?cm-2 at 1.9 V at 90°C, was achieved for this electrolyser configuration in the presence of a moderate noble metal loading (1.5 mg?cm-2 Ir + Ru; 0.5 mg?cm-2 Pt). The interface of IrRuOx with Aquivion provided a 10% enhancement in performance compared to an equivalent interface with a Nafion membrane of similar thickness but characterized by a larger equivalent weight (EW: 1100 g/eq). The enhanced performance essentially derived from a decrease of polarization resistance. This appeared to be due to better interface characteristics between the electrodes and Aquivion® ionomer giving rise to an increased catalyst utilization. Whereas, no significant change in Tafel slope and activation energy was recorded indicating a similar reaction mechanism.