Nitrogen-Doped Graphene Supported Cobalt Oxide Nanocomposite as High Performance Electrocatalyst for Oxygen Reduction Reaction

Nitrogen doped reduced graphene oxide-supported cobalt oxide catalyst has been synthesized by a simple one step chemical reduction method (denoted as NrGO–Co₃O₄) for electrocatalytic oxygen reduction reaction (ORR). This material has been characterized by various instrumental methods. The morphological analysis shows the Co₃O₄ nanocomposites are well set on to the reduced graphene oxide with better dispersion. The X-ray photoelectron spectroscopy (XPS) shows electrochemical reduction has been done successfully with the increasing C/O ratio. Also, the Raman data reveals that the Co is presents with the oxidized form. The electrocatalytic activities have been verified using cyclic voltammetry (CV) and hydrodynamic voltammetry techniques in 0.1 M KOH electrolyte. The as prepared catalyst has shown more positively shifted onset and half wave potential (−0.091 V and −0.276 vs. Ag/AgCl) and high cathodic current density 2.57 mA cm⁻² and high methanol, ethanol crossover tolerance than Pt/C. It is the introduction of strongly bonded cobalt nanocomposite into the network of NrGO that modulate the electronic properties of the NrGO– Co₃O₄, resulting in the superb electrocatalytic performance. The reaction kinetics have confirmed that the ORR at NrGO–Co₃O₄ catalyst follows a four electron transfer reaction process.