Bio-Inspired Leaf-Mimicking Nanosheet/Nanotube Heterostructure as a Highly Efficient Oxygen Evolution Catalyst

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Plant leaves exhibit unique 2D/1D heterostructures optimizing surface reactions and mass transport.
• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for energy conversion technologies.

Purpose of the Study:

• To design and synthesize a bio-inspired 2D/1D cobalt oxide (CoO) heterostructure.
• To investigate the OER performance of the novel CoO nanosheet/nanotube architecture.
• To demonstrate its application in a full water splitting cell.

Main Methods:

• Fabrication of ultrathin CoO nanosheets assembled into nanotube structures.
• Characterization of the CoO heterostructure's morphology, surface area, and electronic properties.
• Electrochemical evaluation of OER activity, including onset potential, current density, and Tafel slope.

Main Results:

• The CoO nanosheet/nanotube heterostructure exhibits an ultrahigh surface area (371 m² g⁻¹).
• Achieved record-high OER performance for cobalt compounds: onset potential ≈1.46 V vs RHE, current density 51.2 mA cm⁻² at 1.65 V vs RHE, and Tafel slope 75 mV dec⁻¹.
• Successfully demonstrated a full water splitting cell powered by a 1.5-V battery.

Conclusions:

• The bio-inspired CoO 2D/1D heterostructure provides an effective platform for efficient OER catalysis.
• This architecture enables enhanced surface reactions, charge transport, and electrolyte diffusion.
• The developed catalyst shows significant potential for electrochemical energy applications, including water splitting.