Magnetic Field-Enhanced 4-Electron Pathway for Well-Aligned Co3 O4 /Electrospun Carbon Nanofibers in the Oxygen Reduction Reaction

Abstract

The sluggish reaction kinetics of the oxygen reduction reaction (ORR) has been the limiting factor for fuel energy utilization, hence it is desirable to develop high-performance electrocatalysts for a 4-electron pathway ORR. A constant low-current (50 μA) electrodeposition technique is used to realize the formation of a uniform Co₃ O₄ film on well-aligned electrospun carbon nanofibers (ECNFs) with a time-dependent growth mechanism. This material also exhibits a new finding of mT magnetic field-induced enhancement of the electron exchange number of the ORR at a glassy carbon electrode modified with the Co₃ O₄ /ECNFs catalyst. The magnetic susceptibility of the unpaired electrons in Co₃ O₄ improves the kinetics and efficiency of electron transfer reactions in the ORR, which shows a 3.92-electron pathway in the presence of a 1.32 mT magnetic field. This research presents a potential revolution of traditional electrocatalysis by simply applying an external magnetic field on metal oxides as a replacement for noble metals to reduce the risk of fuel-cell degradation and maximize the energy output.

Keywords: carbon nanofibers; cobalt; electrocatalysis; electron transfer; magnetic field.