Fe-doped (Ni,Mn)Co2O4 nanorod arrays on Ni foam as highly efficient electrocatalyst for oxygen evolution reaction in alkaline and neutral conditions with superb long-term stability

Abstract

It is drawing increased interest to exploit highly active and durable electrocatalysts based on earth-abundant elements for oxygen evolution reaction (OER). In this work, we successfully synthesized Fe-doped (Ni,Mn)Co2O4 nanorod arrays on nickel foam (labeled as FNMCO/NF) via a anion-exchange route with subsequent annealing process. Experiments showed that the initial concentration of [Fe(CN)6]3- anions could affect the electrocatalytic activity of the as-synthesized FNMCO/NF integral electrode. The FNMCO-6/NF prepared from 6 mM of K3[Fe(CN)6] solution presented the strongest OER electrocatalytic activity. Only overpotential of 242 mV or 449 mV was required to reach the current density of 10 mA cm−2 in 1 M KOH solution or 0.1 M phosphate buffer solution (PBS). Also, after continuously catalyzing for 155 h at 100 mA cm−2 in 1 M KOH solution or 150 h at 20 mA cm−2 in 0.1 M PBS, the overpotential of the as-obtained FNMCO-6/NF electrode rarely varied, implying its superb durability.