Durable oxygen evolution reaction of one dimensional spinel CoFe 2 O 4 nanofibers fabricated by electrospinning.

One dimensional spinel CoFe 2 O 4 nanofibers were synthesized via the electrospinning technique. The nanofibers were calcined at different temperatures. All CoFe 2 O 4 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 CoFe 2 O 4 multi-particle nanochains toward the OER decreases by only 0.78% even after a long period of 80 000 s. Our finding suggests that CoFe 2 O 4 nanofibers with a multi-particle nanochain structure could serve as a new group of OER electrocatalysts with excellent performance.