Stable Bimetallic Polyphthalocyanine Covalent Organic Frameworks as Superior Electrocatalysts

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Highly stable covalent organic frameworks (COFs) are crucial for practical applications.
• Developing robust catalysts for CO2 reduction is essential for carbon cycle management.

Purpose of the Study:

• To design and synthesize ultrastable bimetallic polyphthalocyanine COFs.
• To evaluate the electrocatalytic performance of these COFs for CO2 reduction in an aqueous system.

Main Methods:

• Synthesis of bimetallic polyphthalocyanine COFs via nucleophilic aromatic substitution.
• Characterization of COF stability under harsh conditions.
• Electrocatalytic testing for CO2 reduction, including Faradaic efficiency and turnover frequency measurements.
• Theoretical calculations to elucidate the catalytic mechanism.

Main Results:

• Successfully synthesized robust bimetallic CuPcF8-CoPc-COF and CuPcF8-CoNPc-COF using dioxin linkages.
• Both COFs exhibited strong robustness and high performance in electrocatalytic CO2 reduction.
• CuPcF8-CoNPc-COF achieved 97% Faradaic efficiency and a turnover frequency of 2.87 s-1.
• Eclipsed stacking of metallophthalocyanine units facilitated high-speed electron transfer.

Conclusions:

• The synthesized dioxin-linked COFs offer a new platform for stable and efficient electrocatalysis.
• These findings represent a significant step towards the practical application of COFs in carbon cycle technologies.
• The study expands the library of dioxin-linked COFs and demonstrates their potential for CO2 conversion.