Electrospun porous nanorod perovskite oxide/nitrogen-doped graphene composite as a bi-functional catalyst for metal air batteries

The current generation is not only facing the shortage of fossil fuels in the near future, but also is responsible for preserving the environment for future generations. As a result, the development of clean energy systems is becoming an urgent focus for the research community. Metal air batteries have attracted much attention due to their extremely high energy density, and the rechargeability which is directly governed by the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, we present a new class of hybrid bi-functional catalyst consisting of porous nanorod perovskite La0.5Sr0.5Co0.8Fe0.2O3 (LSCF-PR) combined with nitrogen-doped reduced graphene oxide (NRGO) active towards both ORR and OER. The novel morphology of LSCF-PR is prepared by an electrospinning method, and incorporated into NRGO sheets. Electron microscopy reveals interesting composite morphology in which LSCF-PR is embedded between the sheets of NRGO, forming an efficient LSCF-PR/NRGO composite morphology for the electrochemical oxygen reactions. Electrochemical testing of the LSCF-PR/NRGO composite in alkaline medium results in excellent ORR and OER catalytic activities, verifying the effective combination for bi-functionality. LSCF-PR/NRGO presents not only a comparable or superior performance to state-of-the-art Pt/C catalyst for ORR or OER, respectively, but also better durability. These results highlight the applicability of LSCF-PR/NRGO composite having unique and efficient morphology as a promising bi-functional catalyst for metal air battery applications. (C) 2014 Elsevier Ltd. All rights reserved.