Unrevealing the potential of multicomponent metal-ion incorporation and sulfide modification in cobalt oxide for efficient water oxidation†

The design and development of highly efficient electrocatalysts from transition metals have shown a great potential for substituting precious metal-based electrocatalysts in water-splitting processes. Cobalt oxide is one of the promising materials for oxygen evolution reaction (OER). Modifying the metal oxide by the incorporation of metal ions and substituting sulfides are effective but challenging strategies for achieving efficient OER activities. In the present work, we report the synthesis of CdCoO and CdCoS electrocatalysts deposited on the surface of nickel foam. These electrocatalysts and their composites CdCoO@CuCoO and CdCoS@CuCoS could deliver high catalytic activity for oxygen evolution reaction. The as-synthesized electrocatalysts were characterized using pXRD, FTIR spectroscopy, Raman spectroscopy, XPS, and SEM techniques. The CdCoS showed a lower OER overpotential of 199 mV at a current density of 10 mA cm⁻² and 522 mV at 60 mA cm⁻². The incorporation of Cd²⁺ ions in the cobalt oxides optimized the electronic states around the Co active sites, leading to improved catalytic activities and a lower overpotential compared to other reported cobalt oxides (such as oxyhydroxides). This work emphasizes the effect of metal-ion incorporation and sulfide modification on the OER activity of cobalt oxide for water splitting and provides a multicomponent engineering strategy for designing efficient electrocatalysts.