A facile preparation of CoFe2O4 nanoparticles on polyaniline-functionalised carbon nanotubes as enhanced catalysts for the oxygen evolution reaction

Abstract

Designing and preparing highly efficient non-precious metal electrocatalysts for the oxygen evolution reaction (OER) is extremely urgent but still remains a challenge. In this study, a polyaniline–multiwalled carbon nanotube (PANI-MWCNT) supported, high performance CoFe₂O₄ nanoparticle (NP) loaded electrocatalyst (CoFe₂O₄/PANI-MWCNTs) is synthesized through a novel and simple in situ process under mild conditions. It is found that the introduction of PANI improves the synergistic effect between the CoFe₂O₄ NPs and MWCNTs, so as to promote the electrical conductivity and stability of the catalyst. Meanwhile, PANI provides more active sites to attach CoFe₂O₄ NPs uniformly and tightly. Electrochemical measurement shows that the electrocatalyst displays excellent OER activities at a low overpotential of 314 mV for 10 mA cm⁻² current density and a small Tafel slope of 30.69 mV dec⁻¹ in 1 M KOH at a scan rate of 5 mV s⁻¹. Furthermore, this electrocatalyst exhibits remarkably good durability evaluated by continuously cycling for 1000 cycles and stably working at 0.54 V (vs. Ag/AgCl) for at least 40 h. The achieved results confirm that the CoFe₂O₄/PANI-MWCNT hybrid is an earth-abundant and cheaply fabricated anode material for OER.