Researchers Propose a Novel Approach for Dimensional Engineering of Covalent Organic Frameworks Derived Carbons----Shanghai Advanced Research Institute,Chinese Academy of Sciences

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Researchers Propose a Novel Approach for Dimensional Engineering of Covalent Organic Frameworks Derived Carbons

date： 2023-11-30

Covalent organic frameworks (COFs) are a special class of materials composed of interconnected organic building blocks held together by strong chemical bonds. Featured with evenly distributed atoms and abundant internal empty space, COFs can be utilized as the starting point for developing functional carbon-based materials.

When COFs are subjected to high temperatures, they lose their two-dimensional flat shape and become a three-dimensional structure. In order to obtain the carbon dioxide reduction (CO₂RR) catalysts with large porosity, high conductivity and abundance of edge sites for doped heteroatoms, the structure control of COF derived carbon is of vital importance but is still underexplored.

Recently, a research group led by Prof. ZENG Gaofeng and XU Qing at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, in collaboration with Prof. HE Yue at Shanghai Jiao Tong University, used template-synthesis strategy to first put forward COFs derived carbons in different dimensions to catalyze CO₂RR.

The results were published in SusMat on Nov. 10.

Researchers used different methods to create 1D — 3D carbon materials derived from COFs. For the 1D carbon, a layer of COFs was deposited on carbon nanotubes (CNTs), while for the 2D carbon, COFs were deposited on graphene (Gr). As a comparison, they also directly carbonized the COF precursor to create 3D carbon. The COF precursor used in the experiments was TP-BPY-COF, which was synthesized from specific chemicals using solvothermal methods.

Synthesis of 1D — 3D carbon materials derived from COFs (Image by SARI)

EXAFS spectra showed that the resulting COF-derived carbon materials contained plenty of nitrogen (N) sites, which acted as catalytic centers, particularly in the form of CoN₅. Among the various catalysts tested, the 1D COF-based catalyst exhibited exceptional performance due to its strong affinity for CO₂, a higher number of defective sites, and superior electronic conductivity. These qualities resulted in greater CO₂RR activity and selectivity towards the desired product (CO), compared to the 2D and 3D catalysts.

The results not only present the significance of tailoring the structure of COF-derived carbons to enhance their effectiveness as catalysts in CO₂ reduction reactions, but also provide a new perspective to develop efficient COF-based catalysts. By employing COF-derived carbon materials as catalysts for CO₂ electroreduction, CO₂ can be potentially converted into valuable chemical compounds or even renewable fuels.