Boosting Stability and Activity of Oxygen Evolution Catalyst in Acidic Medium: Bimetallic Ir-Fe Oxides on Reduced Graphene Oxide Prepared through Ultrasonic Spray Pyrolysis

Electrolysis of water in acidic media generally requires noble metals (oxides) to enhance the catalyst activity and durability in the oxygen evolution reaction (OER). Bimetallic Ir-Fe supported on reduced graphene oxide (IFG) is prepared by ultrasonic spray pyrolysis, followed by acid and/or heat treatment. Physical and electrochemical methods are used to elucidate the effect of the physical and chemical properties of the IFG catalysts modified by spray pyrolysis and post treatment on the OER activity and stability under harshly oxidizing conditions in 0.1 M HClO4. The IFG-AHT catalyst synthesized via ultrasonic pyrolysis followed by acid and heat treatment exhibits superior OER activity among the IFG catalysts. The mass activity was two-fold higher and the stability is superior to that of the commercially available Ir catalyst, indicating that the metal (oxide) dissolution rate and the interaction between Ir and the hybrid support affect the cost and lifetime of OER catalysts.