Ultrathin cobalt oxide nanostructures with morphology-dependent electrocatalytic oxygen evolution activity

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Tailoring nanomaterial properties through controlled engineering of composition, structure, and defects is crucial for optimizing catalytic performance.
• Cobalt oxide (CoOx) nanostructures are promising electrocatalysts, but achieving high activity and stability often requires complex synthesis methods.

Purpose of the Study:

• To develop a facile one-step synthesis for ultrathin cobalt oxide nanosheets (UTNS) with abundant oxygen defects and mixed cobalt valences.
• To investigate the electrocatalytic activity of these CoOx UTNS for the oxygen evolution reaction (OER).

Main Methods:

• A one-step hydrothermal protocol was employed to synthesize CoOx UTNS with a thickness of approximately 1.6 nm.
• Characterization of the synthesized CoOx UTNS focused on their composition, defect density, and structural integrity.

Main Results:

• The synthesized ultrathin CoOx nanosheets exhibited a high concentration of oxygen defects and mixed cobalt valences.
• These CoOx UTNS demonstrated superior OER catalytic performance, achieving low overpotentials of 315 mV at 50 mA cm⁻² and 365 mV at 200 mA cm⁻².
• The stable, framework-like architecture of the UTNS contributed to their enhanced OER activity and long-term durability.

Conclusions:

• The facile one-step synthesis provides a scalable route to CoOx nanostructures with tunable properties and defects.
• The engineered CoOx UTNS represent highly active and robust electrocatalysts for the oxygen evolution reaction.
• This strategy holds potential for designing efficient and accessible catalysts for various electrocatalytic applications.