Solution combustion synthesis of highly dispersible and dispersed iridium oxide as an anode catalyst in PEM water electrolysis†
Iridium based materials are state-of-the-art anode catalysts for polymer electrolyte membrane (PEM) water electrolysis thanks to their unmatched stability and performance in the acidic environment of common PEMs like Nafion®. However, their cost restricts their use in large-scale operations. To improve their utilization, identifying a synthesis method of nano-structured iridium oxide with a high active surface area, possibly in a supported form, is of great importance. For this aim, we developed a one-step and cost-effective solution combustion synthesis (SCS) method to prepare nano-structured IrO2 and IrO2-based materials suitable for PEM electrolysis. Among various materials prepared, the iridium oxide incorporated and dispersed in amorphous alumina showed a high surface area (131 m2 g−1) and the current density of 1.78 A cm−2 at 1.8 V which is comparable to the performance of the state-of-the-art commercial membrane electrode assembly (MEA) made of IrRuOx (1.8 A cm−2 at 1.8 V) under PEM water electrolysis. Importantly, the dispersion of the material in the catalyst ink used for the preparation of the MEA was significantly superior compared to that of commercial IrO2 nanoparticles and the amount of the precious metal in the catalyst made by SCS could be reduced by 45 wt% compared to that in the commercial MEA.