Custom-Design of Strong Electron/Proton Extractor on COFs for Efficient Photocatalytic H₂O₂ Production

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Artificial photosynthesis for H₂O₂ production requires efficient electron extraction and proton transfer.
• Covalent organic frameworks (COFs) show promise as photocatalysts but often face kinetic limitations.

Purpose of the Study:

• To design and synthesize a topology-guided, high-crystalline triazine COF for enhanced photocatalytic H₂O₂ production.
• To investigate the role of polar functional groups in facilitating electron and proton transfer for artificial photosynthesis.

Main Methods:

• Topology-guided synthesis of triazine-based COFs.
• Decoration of COFs with polar oxygen functional groups (sulfonic acid and carboxyl).
• Photocatalytic evaluation of H₂O₂ production under visible light irradiation.

Main Results:

• The sulfonic acid-functionalized COF (SO₃H-COF) exhibited superior H₂O₂ production activity (4971 μmol g⁻¹ h⁻¹) compared to carboxyl- and hydrogen-functionalized COFs.
• The SO₃H-COF demonstrated a built-in electric field and hydrophilic surface, facilitating continuous electron and proton transport.
• A quantum yield of 15% at 400 nm was achieved, outperforming most reported COF-based photocatalysts.

Conclusions:

• Polar functional groups, particularly sulfonic acid, significantly enhance photocatalytic H₂O₂ production by accelerating proton-coupled electron transfer (PCET).
• The developed SO₃H-COF represents a highly efficient photocatalyst for visible-light-driven H₂O₂ synthesis, advancing artificial photosynthesis.