(Invited) Perovskite Oxide As High Performance Bifunctional Catalyst in Alkaline Solution

Abstract

The global energy crisis coupling with the consumption of fossil fuels and the associated environmental issues, has stimulated extensive interest in searching for clean, efficient and sustainable energy storage and conversion systems. Producing oxygen through an OER process can be promising when effective catalysis of water oxidation into oxygen molecules could be achieved. Therefore, developing an efficient OER electrocatalyst is vital to the new generation of electrochemical storage and conversion devices such as electrolyzer, hydrogen production from water and metal-air batteries. However, there are still several challenges that have to be solved for the electrochemical water oxidation process to become economically attractive One of them is associated with the high overpotential and thereby energy losses at the electrode, where OER is taken place with four electron transfer, according to the following overall reaction: 2H 2 O (l) + 4 × 1.23 eV → O 2 + 4H + + 4e - (1) Oxygen reduction reaction (ORR), reversible reaction of OER, also play an important role in electrochemical energy storage devices including fuel cell and metal air battery. Advanced ABO 3 perovskite oxides with improved catalytic properties have been extensively developed and modified as bifunctional catalyst because of their high versatility in composition, crystalline and electronic structure. In this paper, (La 0.8 Sr 0.2 ) 1-x Mn 1-x Ir x O 3 (x=0, 0.05 and 0.1) nanoparticles with particle size of 20-50 nm were succesfully developed as the superior bifuctional catalyst in alkaline solution. The onset potential for ORR is around 0.92V, which is only 50 mv negative shift for state of art Pt/C catalyst while the onset potential for OER is around 1.55 V, which is comparabel with a state of art IrO 2 catalyst.