Selectivity

Nanotechnology

Electrode

Organic chemistry

Covalent bond

Combinatorial chemistry

Nucleophilic aromatic substitution

Electron transfer

Engineering

Faraday efficiency

Catalysis

Nucleophilic substitution

Physical chemistry

Aqueous solution

Chemistry

Materials science

Covalent organic framework

Bimetallic strip

Stacking

Chemical engineering

Electrochemistry

Journal of the American Chemical Society

The development of highly stable covalent organic frameworks (COFs) is extremely compelling for their implementation in practical application. In this work, we rationally designed and synthesized new kinds of ultrastable bimetallic polyphthalocyanine COFs, which are constructed with the dioxin linkage through the nucleophilic aromatic substitution between octahydroxylphthalocyanine and hexadecafluorophthalocyanine. The resulting bimetallic CuPcF8-CoPc-COF and CuPcF8-CoNPc-COF exhibited strong robustness under harsh conditions. The eclipsed stacking mode of metallophthalocyanine units supplies a high-speed pathway for electron transfer. With these structural advantages, both COFs displayed considerable activity, selectivity, and stability toward electrocatalytic CO2 reduction in an aqueous system. Notably, CuPcF8-CoNPc-COF showed a faradaic efficiency of 97% and an exceptionally high turnover frequency of 2.87 s-1, which is superior to most COF-based electrocatalysts. Furthermore, the catalytic mechanism was well demonstrated by using a theoretical calculation. This work not only expanded the variety of dioxin-linked COFs, but also constituted a new step toward their practical use in carbon cycle.

Stable Bimetallic Polyphthalocyanine Covalent Organic Frameworks as Superior Electrocatalysts