One dimensional spinel CoFe2O4 nanofibers were synthesized via the electrospinning technique. The nanofibers were calcined at different temperatures. All CoFe2O4 nanofibers show excellent oxygen evolution reaction (OER) performance. The nanofibers calcined at 750 °C have a multi-particle nanochain structure. The nanochain exhibits excellent catalytic performance for OER in 1 M KOH (pH = 14) producing a current density of 10 mA cm−2 at an overpotential of 0.34 V, and the small onset potential of 1.32 V versus RHE, better than that of the commercial Ir/C (20%) catalyst. Furthermore, the stability of CoFe2O4 multi-particle nanochains toward the OER decreases by only 0.78% even after a long period of 80 000 s. Our finding suggests that CoFe2O4 nanofibers with a multi-particle nanochain structure could serve as a new group of OER electrocatalysts with excellent performance.
