Durable oxygen evolution reaction of one dimensional spinel CoFe₂O₄ nanofibers fabricated by electrospinning

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.