Precise Design of D-A Type Metal Covalent Organic Framework for Regulating Intramolecular-Charge-Transfer toward H₂O₂...

Area of Science:

• Materials Science
• Photocatalysis
• Organic Chemistry

Background:

• Donor-acceptor (D-A) effects regulate photogenerated carrier separation for enhanced photocatalysis.
• The molecular-level correlation between structure and charge transport in organic photocatalysts is underexplored.

Purpose of the Study:

• To synthesize and investigate two D-A type metal-covalent organic frameworks (MCOFs): Tap-MCOF and Bpy-MCOF.
• To elucidate the relationship between molecular structure, charge transport, and photocatalytic performance.

Main Methods:

• Synthesis of two MCOFs, Tap-MCOF and Bpy-MCOF, using specific organic linkers and copper.
• Characterization of MCOFs' structures and electronic properties.
• Evaluation of photocatalytic performance for H2O2 production under visible light.

Main Results:

• Tap-MCOF demonstrated a significantly higher H2O2 production rate (288.58 μmol g⁻¹ h⁻¹) compared to Bpy-MCOF.
• Tap-MCOF exhibited narrower band gaps and enhanced photoinduced carrier separation, attributed to an intensified D-A effect.
• Higher transient photocurrent response in Tap-MCOF indicated superior charge separation and transport efficiency.

Conclusions:

• The intensified D-A effect in Tap-MCOF is crucial for its enhanced photocatalytic activity.
• Molecular-level design of MCOFs offers a viable strategy to optimize carrier separation and photocatalytic efficiency.
• The findings provide insights into organic semiconducting catalysts for oxygen reduction reaction (ORR) and water oxidation reaction (WOR).