Cobalt Nanoparticles/Black Phosphorus Nanosheets: An Efficient Catalyst for Electrochemical Oxygen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Black phosphorus (BP) nanosheets (NS) show promise as oxygen evolution reaction (OER) electrocatalysts due to high conductivity and active sites.
• The inherent instability of ultrathin BP NSs, caused by exposed lone pair electrons, limits their durability in long-term OER catalysis.

Purpose of the Study:

• To engineer the electronic structure of BP NSs to enhance their stability and catalytic activity for OER.
• To develop a novel hybrid electrocatalyst combining BP NSs with cobalt nanoparticles.

Main Methods:

• A facile solvothermal reduction route was employed to synthesize cobalt nanoparticles in situ on BP NSs, creating a Co/BP NSs hybrid electrocatalyst.
• Characterization of the electronic structure revealed electron migration from BP to Co due to differing Fermi levels.

Main Results:

• The Co/BP NSs electrocatalyst exhibited excellent OER performance with a low overpotential of 310 mV at 10 mA cm⁻².
• The hybrid catalyst demonstrated outstanding stability in alkaline media, attributed to the preferential migration of active lone pairs from BP defects.
• The electronic structure engineering effectively retained BP NSs' stability and high hole mobility.

Conclusions:

• The Co/BP NSs hybrid electrocatalyst presents a viable, stable, and high-performance alternative to commercial iridium dioxide (IrO₂) for OER.
• This research offers valuable insights into utilizing defects for electronic structure engineering in BP NSs and designing novel hybrid electrocatalysts.