Thinly-walled NiFe2O4 nanotubes derived from Ni, Fe, N-codoped carbon nanofibers toward oxygen evolution reaction

Abstract

NiFe₂O₄ has emerged as an efficient oxygen evolution reaction (OER) electrocatalyst, with outstanding stability in alkaline media and excellent redox properties. In order to further improve the catalytic performance, thinly-walled NiFe₂O₄ nanotubes (NiFe₂O₄-NTs), efficiently derivable from Ni, Fe, N-codoped carbon nanofibers, were innovatively synthesized through a sequential route combing hydrothermal, electrospinning, and high-temperature sintering in this work. The NiFe₂O₄-NTs possess large diameter of around 120 nm and their thickness of the tube wall is only about 10 nm. The surface properties of NiFe₂O₄ can be adjusted by forming the Ni-N/Fe-N bonds. Excitingly, largely exposed active surface area and boosted catalytic reaction kinetics toward oxygen evolution reaction are realized. The required overpotential to deliver 10 mA cm⁻² is only 331 mV, accompanied with favorable Tafel slope of only 51.8 mV dec⁻¹, small charge transfer resistance, and superior reaction stability.