The role of Nafion content in sputtered IrO2 based anodes for low temperature PEM water electrolysis

The optimal amount of Nafion ionomer applied on IrO2 sputter-deposited electrodes on Ti covered carbon paper was investigated during low temperature PEM water splitting. Different Nafion ionomer loadings were applied on IrO2 electrodes and their performance towards the oxygen evolution reaction was evaluated. An optimum Nafion loading of 1.5 mg cm−2 was found which gives a current density of 0.18 A cm−2 at 1.75 V and 60 °C. The anode selectivity to O2 versus CO2 production was 100% and no signs of performance deterioration were observed over periods of several days.

► Stable water electrolysis was achieved in a PEM with 100% selectivity to oxygen. ► IrO2 sputtered anodes on Ti covered C-paper were used for the water splitting. ► The Nafion content on the anode affects the rate of O2 evolution and selectivity. ► Nafion ionomer addition protects the C–IrO2 active sites for carbon oxidation. ► No signs of performance deterioration were observed over periods of several days.