Three-Dimensional Phenazine-Integrated Covalent Organic Framework for Efficient Electrosynthesis of H₂O₂ Under...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Covalent organic frameworks (COFs) show potential for electrocatalytic hydrogen peroxide (H2O2) synthesis.
• Existing COF catalysts are often limited to 2D structures and alkaline environments, hindering practical use.

Purpose of the Study:

• To design and synthesize three-dimensional (3D) COFs for efficient H2O2 electrosynthesis under neutral conditions.
• To investigate the impact of phenazine incorporation on COF structure and catalytic performance.

Main Methods:

• Synthesis of a 3D COF (BCTA-PZDC-COF) using phenazine units.
• Electrochemical evaluation of the 3D COF for the 2-electron oxygen reduction reaction (ORR) in neutral electrolyte.
• Comparison with a 2D benzene-linked COF (BCTA-TPTC-COF).
• Theoretical studies to understand the mechanism of action.

Main Results:

• The 3D BCTA-PZDC-COF achieved 91% H2O2 selectivity and a mass activity of 4.46 A g-1, significantly outperforming the 2D counterpart.
• The catalyst demonstrated a production rate of 6.7 mol g-1 h-1 with 90.6% Faradaic efficiency in a flow cell.
• Phenazine incorporation enhanced electronic properties and charge transfer dynamics.

Conclusions:

• The developed 3D COF offers an efficient and stable platform for H2O2 electrosynthesis in neutral media.
• The phenazine structure facilitates optimal intermediate adsorption, boosting catalytic performance.
• This strategy enables the design of COF electrocatalysts for environmentally friendly applications.