One-Dimensional Covalent Organic Frameworks for the 2e^- Oxygen Reduction Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Two-dimensional covalent organic frameworks (2D COFs) are utilized in electrocatalysis due to their structural variety.
• Challenges exist in atom utilization efficiency as catalytic sites in basal layers are inaccessible to electrolytes.

Purpose of the Study:

• To investigate the application of one-dimensional covalent organic frameworks (1D COFs) for the 2-electron oxygen reduction reaction (ORR).
• To enhance catalytic site accessibility and atom utilization in COF-based electrocatalysts.

Main Methods:

• Synthesis of 1D COFs using different four-connectivity blocks.
• Characterization of 1D COFs for crystallinity, surface area, and chemical stability.
• Electrochemical evaluation of 1D COFs for ORR activity and selectivity.

Main Results:

• 1D COFs exhibited good crystallinity, high surface areas, and excellent chemical stability.
• 1D COFs demonstrated a 4.8-fold larger electrochemically active surface area compared to 2D COFs.
• 1D COFs achieved higher H2O2 selectivity (85.8%) and activity (TOF 0.051 s⁻¹) for ORR than 2D COFs (72.9%, 0.032 s⁻¹).

Conclusions:

• 1D COFs offer superior performance for the 2e⁻ ORR due to increased accessibility of catalytic sites.
• Low-dimensional COFs present a promising avenue for developing advanced electrocatalytic systems.