Magnetic Field-Enhanced 4-Electron Pathway for Well-Aligned Co₃O₄/Electrospun Carbon Nanofibers in the Oxygen Reduction Reaction

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 Co₃O₄ 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 Co₃O₄/ECNFs catalyst. The magnetic susceptibility of the unpaired electrons in Co₃O₄ 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.