Nanoporous IrO2 catalyst with enhanced activity and durability for water oxidation owing to its micro/mesoporous structure

Abstract

Herein, we report a nanoporous IrO₂ catalyst with a surface area of 363.3 m² g⁻¹, the highest ever reported. The IrO₂ catalysts were prepared by a facile ammonia-induced pore-forming method, and efficiently scaled up to several kilograms. Bimodal micro/mesopores were created at once without using a template. For the IrO₂ (1 : 100)-450 °C (H₂IrCl₆ : NH₃·H₂O of 1 : 100) catalyst, the overpotential to attain a current density of 10 mA cm⁻² for water oxidation was only 282 mV, and furthermore, its excellent durability was confirmed by accelerated durability tests. Moreover, the overall voltage to achieve a current density of 1000 mA cm⁻² in a water electrolysis cell was only 1.649 V, making IrO₂ (1 : 100)-450 °C a highly attractive catalyst for water electrolysis applications.