Solution combustion synthesis of highly dispersible and dispersed iridium oxide as anode catalyst in PEM water electrolysis

Abstract

<p class="RSCB01COMAbstract"> <span class="06CHeading"><span lang="EN-GB">Iridium based materials are the 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&reg;. However, their uses on a large-scale operation are cost-restrictive. To improve their wider utilization, identifying a synthesis method of nano-structured iridium oxide with 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 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 MEA made of IrRuO_x (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 membrane electrode assembly (MEA) was significantly superior compared to 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.</span></span><span class="06CHeading"><span lang="EN-GB"><o:p></o:p></span></span></p>