Highly Active Cobalt‐Based Electrocatalysts with Facile Incorporation of Dopants for Oxygen Evolution Reaction

In‐situ formation of electroactive cobalt species for the oxygen evolution reaction is simply achieved by applying an anodic bias to a commercially available cobalt precursor and Nafion binder mixture coated on a glassy carbon electrode. Without needing energy‐intensive materials preparation steps and noble metals, a low overpotential of 322 mV at 10.2 mA/cm2 and a high current density of more than 300 mA/cm2 at 1.7 V were obtained in 1 M KOH. An operando electrochemical Raman spectroscopy study confirmed the formation of cobalt oxyhydroxide species and the iron stimulated the equilibrium state between Co3+ and Co4+. The iron present in the alkali electrolyte or ink solution effectively activated the cobalt species, and most of the 1st row transition metals could also enhance the catalytic performance. The concept presented here is one of the simplest strategies for preparing highly active electrocatalysts and is very flexible for the replacement of cobalt by other transition metals.

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