Preparation and electrocatalytic properties of spinel oxide FeCo2O4

Spinel oxides of special crystal structure and composition, have been widely applied in biotechnology, laser, sensor technologies, and conversion reaction. In this work, FeCo₂O₄ powders were prepared by hydrothermal, solid-state, and sol-gel methods to explore the optimal synthesis process of spinel oxides. The effects of annealing temperature on spinel structure were also investigated. In addition, the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) electrocatalytic activities, and practical applications of FeCo₂O₄ in electrochemical energy conversion devices were explored. Specifically, single-phase FeCo₂O₄ with smaller particle sizes can be prepared by a procedure including the hydrothermal method and subsequent annealing at 900°C. Moreover, the composite of FeCo₂O₄ and EC600JD shows splendid OER and ORR activities. And FeCo₂O₄ spinel oxide reaches a maximum power density of 97.63 mWꞏcm^-2 when applied as air cathode of the aluminum-air battery. Our work demonstrates that FeCo₂O₄ with a simple synthesis process and preeminent electrocatalytic performance is a promising catalyst for metal-air batteries.