Ultrasound-treated metal-organic framework with efficient electrocatalytic oxygen evolution activity

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Metal-organic frameworks (MOFs) show promise as electrocatalysts but suffer from poor conductivity and activity for oxygen evolution reactions (OER).
• Pyrolysis of MOFs into composite catalysts is common, but often leads to structural collapse and loss of active sites.
• Two-dimensional (2D) metal-organic framework nanosheets (MONs) combine MOF advantages with rapid electron transfer, offering significant catalytic potential.

Purpose of the Study:

• To develop a direct electrocatalyst for OER using MOFs.
• To synthesize Co-MONs via a simple top-down approach suitable for direct application.
• To enhance catalytic performance by controlling the exposed lattice planes for increased active sites and ion transport.

Main Methods:

• A simple top-down synthesis approach was employed to create Co-MONs.
• Ultrasonic bath treatment (40 KHz, 100 W) was used to control the exposed lattice planes.
• Electrochemical performance for OER was evaluated, including current density and overpotential.

Main Results:

• A simple top-down method successfully synthesized Co-MONs.
• The optimized Co-MONs demonstrated efficient direct electrocatalytic activity for OER.
• Achieved 10 mA cm⁻² at an overpotential of 309 mV with a Tafel slope of 75.71 mV dec⁻¹.

Conclusions:

• Co-MONs can be directly used as efficient electrocatalysts for OER, bypassing the need for pyrolysis.
• The ultrasonic treatment method effectively exposes active sites and improves ion transport, leading to enhanced catalytic performance.
• This work presents a promising strategy for utilizing 2D MOFs in catalysis.