Nitrogen-Doped Mixed-Phase Cobalt Nanocatalyst Derived from a Trinuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complex for High-Performance Oxygen Evolution Reaction.

Because of a continuous increase in energy demands and environmental concerns, a focus has been on the design and construction of a highly efficient, low-cost, environmentally friendly, and noble-metal free electrocatalyst for energy technology. Herein we report facile synthesis of the mixed-valence trinuclear cobalt complex 1 by the reaction of 2-amino-1-phenylethanol and CoCl2·6H2O in methanol as the solvent at room temperature. Further, 1 was reduced by using aqueous N2H4 as a simple reducing agent, followed by calcination at 300 °C for 3 h, yielding a nitrogen-doped mixed phase cobalt [β-Co(OH)2 and CoO] nanocatalyst (N@MPCoNC). Both 1 and N@MPCoNC were characterized by various physicochemical techniques. Moreover, 1 was authenticated by single-crystal X-ray diffraction studies. The hybrid N@MPCoNC reveals a unique electronic and morphological structure, offering a low overpotential of 390 mV for a stable current density of 10 mA cm-2 with high durability. This N@MPCoNC showed excellent electrocatalytic as well as photocatalytic activity for oxygen evolution reaction compared to 1.