Efficient Electronic Transport in Partially Disordered Co3O4 Nanosheets for Electrocatalytic Oxygen Evolution Reaction

The design and synthesis of high-performance electrocatalysts for the oxygen evolution reaction (OER) are critical factors for the development of electrochemical energy storage and conversion systems. Here, a remarkable enhancement in OER activity is reported by introducing cerium into Co3O4. An electrode made of Co3-xCexO4 requires a much lower overpotential than that of Co3O4 nanosheets to reach a current density of 100 mA cm(-2), and it is stable for at least 100 h with high intrinsic activity. The structure becomes partially disordered after Ce doping, thus exposing more active sites. In situ Raman spectra reveals a polyhedral distortion of Co3O4 accompanying the oxygen evolution process. Moreover, the active cobalt (oxy)hydroxide phase in Co3-xCexO4 appears at lower bias as compared with Co3O4. It is proposed that the enhanced activity is ascribed to the structural disorder and electronic transport after the introduction of cerium.