A Novel Π-D Conjugated Cobalt Tetraaza[14]Annulene Organic Framework for Efficient Electrocatalytic Co2 Reduction

Tetraaza[14]annulenes (TAA) are a synthetic macrocycles analogue to porphyrins. However, there are almost no reports about the synthesis of metal organic frameworks based on TAA and neither on their use as electrocatalysts. The study of new catalysts to promote an efficient electrochemical conversion of carbon dioxide to valuable chemicals is a promising approach to relieve the pressure of carbon emissions and realize the carbon cycle. Herein, we first report the synthesis of a novel tetraaza[14]annulene (TAA) based organic framework by a non-template method. The framework is used as ligand to construct a π-d conjugated cobalt-based organic framework (Poly-TAA-Co) with CoN 4 structure which is supported on multi-wall carbon nanotubes (CNTs) to work as an atomically dispersed efficient molecular based electrocatalyst for the CO 2 reduction reaction (CO 2 RR). The resulting catalyst (Poly-TAA-Co-CNT) exhibits excellent performance, with a 90% CO faradaic efficiency, a low overpotential (390 mV) and good stability in 0.5 M KHCO 3 aqueous solution. Density functional theory calculations confirmed the Co-TAA to be excellent active sites for electrocatalytic CO 2 RR. This work not only inspires the design of novel organic frameworks based on TAA macromolecules, but also paves the way to the development and application of new molecular-based catalysts for electrocatalytic CO 2 RR