Semiconducting Polyaromatic Covalent Organic Frameworks Constructed through Self-Aldol Condensation.

Area of Science:

• Reticular Chemistry
• Materials Science
• Electrochemistry

Background:

• Single-component self-polymerization is a key strategy for synthesizing semiconducting covalent organic frameworks (COFs).
• Developing efficient, stable, and metal-free electrocatalysts for the oxygen reduction reaction (ORR) is crucial for energy applications.

Purpose of the Study:

• To synthesize novel semiconducting polyaromatic COFs with all-fused-ring conjugation structures.
• To evaluate their performance as metal-free electrocatalysts for the oxygen reduction reaction (ORR).

Main Methods:

• Synthesis of two semiconducting polyaromatic COFs via self-aldol condensation of indanone-based building blocks.
• Characterization of their structural, electronic, and electrochemical properties.
• Evaluation of their electrocatalytic activity and stability for the ORR.

Main Results:

• The synthesized COFs exhibit n-type semiconducting properties with high crystallinity and exceptional stability in harsh acidic and alkaline conditions.
• Achieved record electrical conductivity (5.5 × 10⁻³ S cm⁻¹) and charge carrier mobility (0.62 cm² V⁻¹ s⁻¹) among n-type semiconducting COFs.
• Demonstrated excellent metal-free electrocatalytic activity for ORR, with one COF achieving a half-wave potential of 0.77 V and long-term durability.

Conclusions:

• The study expands the diversity of semiconducting COFs and introduces a new paradigm for developing high-performance metal-free ORR electrocatalysts.
• The developed polyaromatic COFs offer a promising alternative to metal-based catalysts due to their superior conductivity, stability, and catalytic efficiency.