CoN₅ Sites Constructed by Anchoring Co Porphyrins on Vinylene‐Linked Covalent Organic Frameworks for Electroreduction of Carbon Dioxide

Abstract

Developing effective electrocatalysts for CO2 reduction (CO2RR) is of critical importance for producing carbon‐neutral fuels. Covalent organic frameworks (COFs) are an ideal platform for constructing catalysts toward CO2RR, because of their controllable skeletons and ordered pores. However, most of these COFs are synthesized from Co‐porphyrins or phthalocyanines‐based monomers, and the available building units and resulting catalytic centers in COFs are still limited. Herein, Co‐N5 sites are first developed through anchoring Co porphyrins on an olefin‐linked COF, where the Co active sites are uniformly distributed in the hexagonal networks. The strong electronic coupling between Co porphyrins and COF is disclosed by various characterizations such as X‐ray absorption spectroscopy (XAS) and density functional theory calculation (DFT). Thanks to the CoN5 sites, the catalytic COF shows remarkable catalytic activity with Faraday efficiencies (FECO) of 84.2–94.3% at applied potentials between −0.50 and −0.80 V (vs RHE), and achieves a turnover frequency of 4578 h–1 at −1.0 V. Moreover, the theoretical calculation further reveals that the CoN5 sites enable a decrease in the overpotential for the formation COOH*. This work provides a design strategy to employ COFs as scaffold for fabricating efficient CO2 electrocatalysts.

Dimensional engineering of covalent organic frameworks derived carbons for electrocatalytic carbon dioxide reduction

“…No intensity wavelet corresponding to Co-Co was observed, and the Co atoms were coordinated by five N atoms (Co-N 5 ). 49 Therefore, the newly catalytic sites (CoN 5 ) were successfully constructed by immobilizing CoPor on the COF-derived carbons.…”

Facile synthesis of three-dimensional Co/N co-doped carbon nanocuboids for an enhanced oxygen reduction reaction

“…Currently, conventional synthetic approaches for Co–N–C catalysts rely on high temperature calcination. This favors the production of active and diverse Co–N x sites (Co–N 5 , 39 Co–N 4 , 40 Co–N 3 41 and Co–N 2 42 ), whereas it generates non-active Co–carbide and Co NPs. 43 Additionally, not all Co–N x sites are regarded as “active sites” contributing to the ORR performance.…”

Diatomic molecule catalysts toward synergistic electrocatalytic carbon dioxide reduction

“…The electrochemical conversion of carbon dioxide (CO 2 ) into value-added products, such as carbon monoxide (CO), formic acid, ethylene, and ethanol, by utilizing renewable energy sources is an appealing approach to achieving carbon neutrality and energy storage. 1,2 Various inexpensive and abundant transition metal-based electrocatalysts, such as those based on Fe, [3][4][5][6] Co, [7][8][9][10] Ni, [11][12][13][14][15][16] Cu, [17][18][19] and Bi (ref. [20][21][22], have been widely used to catalyze the CO 2 reduction reaction (CO 2 RR).…”