摘要

Ba0.9Co0.5Fe0.4Nb0.1O3 (BCFN) perovskite has been synthesized by a solid-state reaction method, and characterized by XRD, SEM, BET. This oxide has a porous structure and a specific surface area of 10.24 m(2) g(-1) after ball-milled 24 h. The catalytic activity of the oxide for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) in 0.1 M KOH solution has been studied by using a rotating ring-disk electrode (RRDE) technique. RRDE results show that the ORR mainly favors a direct four electron pathway, and a maximum cathodic current density of -5.70 mA cm(-2) at 2500 rpm was obtained, which is close to that of Pt/C (20 wt.% Pt on carbon) electrocatalyst in the same testing conditions. Compared with behaviors of pure C and Pt/C electrode, a lower onset potential of BCFN for OER is observed, and a bigger anodic current at the same applied potential is obtained. Considering small surface area of the BCFN catalyst, a big overpotential is given in the discharge-charge curves. However, the outputs of 2032 coin Li-air batteries in a dry gas mixture composed of 80 vol.% pure N-2 and 20 vol.% pure O-2 demonstrated that BCFN could be a potential bifunctional catalyst for the Li-air battery.