A bifunctional hybrid electrocatalyst for oxygen reduction and oxygen evolution reactions: Nano-co3o4-deposited la0.5sr0.5mno3 via infiltration

Abstract

For rechargeable metal–air batteries, which are a promising energy storage device for renewable and sustainable energy technologies, the development of cost-effective electrocatalysts with effective bifunctional activity for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a challenging task. To realize highly effective ORR and OER electrocatalysts, we present a hybrid catalyst, Co3O4-infiltrated La0.5Sr0.5MnO3-δ (LSM@Co3O4 ), synthesized using an electrospray and infiltration technique. This study expands the scope of the infiltration technique by depositing ~18 nm nanoparticles on unprecedented ~70 nm nano-scaffolds. The hybrid LSM@Co3O4 catalyst exhibits high catalytic activities for both ORR and OER (~7 times, ~1.5 times, and ~1.6 times higher than LSM, Co3O4, and IrO2, respectively) in terms of onset potential and limiting current density. Moreover, with the LSM@Co3O4, the number of electrons transferred reaches four, indicating that the catalyst is effective in the reduction reaction of O2 via a direct four-electron pathway. The study demonstrates that hybrid catalysts are a promising approach for oxygen electrocatalysts for renewable and sustainable energy devices.