Preparation of CoFeO-Doped TiO Nanofibers by Electrospinning and Annealing for Oxygen Electrocatalysis.

In this paper, catalyst precursor fibers were prepared by a sol gel method combined with an electrospinning method using tetrabutyl titanate as a titanium source, cobalt acetylacetonate as a cobalt source, and iron acetylacetonate as an iron source. CoFe@TiO nanofibers (NFs) with a bimetallic spinel structure were formed after thermal annealing, which have dual-functional catalytic activity. With the molar ratio of Co and Fe coming to 1:1, a typical spinel CoFeO structure was generated in CoFe@TiO NFs. At a load of only 28.7 μg·cm, CoFe@TiO NFs not only have a low overpotential (284 mV) and Tafel slope (54 mV·dec) in the oxygen evolution reaction but also show a high initial potential (0.88 V) and limiting current density (6.40 mA·cm) in the oxygen reduction reaction. Meanwhile, CoFe@TiO NFs exhibit good durability, cycle stability, and dual-function catalysis.