Defect-Driven Evolution of Oxo-Coordinated Cobalt Active Sites with Rapid Structural Transformation for Efficient...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Metal-organic frameworks (MOFs) are promising precatalysts for electrocatalysis.
• Controlling MOF structural evolution and understanding in situ active sites during electrolysis is challenging.

Purpose of the Study:

• To develop a strategy for fine-tuning MOF surface nature to enhance electrocatalytic performance.
• To investigate the role of in situ-derived active sites in MOF-based electrocatalysts.

Main Methods:

• Facile thermal treatment of Cobalt-based MOFs (Co-MOFs).
• Operando spectroscopic characterization.
• Atomistic simulations.

Main Results:

• Transformed Co-N4 configuration to a defective Co-N3-oxo structure.
• Achieved enhanced oxygen evolution reaction (OER) activity (256 mV overpotential at 10 mA cm⁻²).
• Demonstrated excellent durability (100 h) and balanced binding of OER intermediates.

Conclusions:

• The defective Co-N3-oxo structure facilitates rapid transition to homogeneous oxyhydroxides.
• Optimized surface Co-O bonding and μ₂-O-Co³⁺ sites enhance OER activity.
• MOF surface reconstruction is an effective strategy for designing high-performance electrocatalysts.