Improvement of the Activity and Stability towards Oxygen Evolution Reaction by Iridium Oxide prepared using modified Adams Fusion Method

Abstract

Recently, interests in hydrogen production through proton exchange membrane water electrolysis (PEMWE) has increased rapidly. PEMWE has benefits at high current operation and gas purity compared to the alkaline water electrolysis, despite high anodic overpotential and high costs due to expensive anode catalysts (Ru, Ir). Since iridium oxide catalysts are stable and active in oxygen evolution reaction (OER), researches have been focusing on increasing the activity and durability of iridium-based catalysts. In this study, to increase OER activity, micro and mesoporous iridium oxide (IrO2) with the high surface area was synthesized through Adams fusion method after coordinating iridium precursor with a chelating agent. X-ray diffraction pattern reveals that iridium oxide is well synthesized with crystallite size of 3.5 nm. N2 adsorption/desorption isotherms showed that synthesized IrO2 has a high surface area of 380m2/g with micro and mesopores, which implies that the OER activity could be improved by increased surface area. From the half-cell test, synthesized IrO2 displayed the high OER activity of 1.58V at 10mA/cm2 which is 20mV higher than iridium oxide synthesized by conventional Adams fusion method. Also, excellent durability was confirmed by 2 hours of chronopotentiometry at 10mA/cm2.