Sub‐Stoichiometric Covalent Organic Frameworks

Qian, Cheng; Li, Xing; Teo, Wei Liang; Gao, Qiang; Wei, Wei

doi:10.1002/adfm.202313905

Cited by 8 publications

(1 citation statement)

References 65 publications

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“…Note that these values are higher than those in most of the reported materials (Table S1) [3,5,7,13,[16][17][18]21,24,28,42,. The 4-connected and 3-connected building units are both planar π-conjugated molecular structures; however, the combination of 4-connected and 3-connected building units produces 3D extended networks [88,89]. Despite the amorphous structure of the CMPs obtained in this work (Figure S7), it can be predicted that their networks will grow preferentially along the predesigned topological structure to the present 3D skeletons.…”

Section: Resultsmentioning

confidence: 80%

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Li,

Yan,

et al. 2024

Molecules

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The effective capture and recovery of radioiodine species associated with nuclear fuel reprocessing is of significant importance in nuclear power plants. Porous materials have been proven to be one of the most effective adsorbents for the capture of radioiodine. In this work, we design and synthesize a series of conjugated microporous polymers (CMPs), namely, TPDA–TFPB CMP, TPDA–TATBA CMP, and TPDA–TECHO CMP, which are constructed based on a planar rectangular 4-connected organic monomer and three triangular 3-connected organic monomers, respectively. The resultant CMPs are characterized using various characterization techniques and used as effective adsorbents for iodine capture. Our experiments indicated that the CMPs exhibit excellent iodine adsorption capacities as high as 6.48, 6.25, and 6.37 g g−1 at 348 K and ambient pressure. The adsorption mechanism was further investigated and the strong chemical adsorption between the iodine and the imine/tertiary ammonia of the CMPs, 3D network structure with accessible hierarchical pores, uniform micromorphology, wide π-conjugated structure, and high-density Lewis-base sites synergistically contribute to their excellent iodine adsorption performance. Moreover, the CMPs demonstrated good recyclability. This work provides guidance for the construction of novel iodine adsorbent materials with high efficiency in the nuclear power field.

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Section: Resultsmentioning

confidence: 80%

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Li,

Yan,

et al. 2024

Molecules

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Constructing benzothiadiazole‐based donor‒acceptor covalent organic frameworks for efficient photocatalytic H₂ evolution

Huang,

Gao,

Huang

et al. 2024

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Donor‒acceptor covalent organic frameworks (D‒A COFs) have been regarded as promising materials for photocatalytic water splitting because of their tunable band gaps. However, their efficiency is hindered by fast charge recombination and low photostability. Herein, we proposed a donor structural engineering strategy for improving the photocatalytic activity of D‒A COFs to tackle these problems. Two benzothiadiazole‐based D‒A COFs (DHU‐COF‐BB and DHU‐COF‐BP) with distinct donors were prepared for photocatalytic H2 evolution reaction (HER). As a comparison, DHU‐COF‐TB without benzothiadiazole moieties was also designed and synthesized. Impressively, the photocatalytic H2 production rate of DHU‐COF‐BB reaches 12.80 mmol g−1 h−1 under visible light irradiation (≥420 nm), which was nearly 2.0 and 3.1 times higher than that of DHU‐COF‐BP (6.47 mmol g−1 h−1) and DHU‐COF‐TB (4.06 mmol g−1 h−1), respectively. In addition, the apparent quantum efficiency (AQE) of DHU‐COF‐BB was up to 5.04% at 420 nm. Photocatalytic and electrochemical measurements indicate that the enhanced hydrogen evolution activity of DHU‐COF‐BB can be ascribed to the introduction of appropriate benzene moiety into the donors, which increases the charge separation efficiency and thereby suppresses the electron‒hole recombination. Density functional theory (DFT) calculations revealed that both triphenylamine and benzothiadiazole units are the main active sites for HER over the DHU‐COF‐BB. This work provides new insight into the photocatalytic hydrogen production activity of D‒A COFs by a donor structural engineering strategy.

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Taming Two‐Dimensional Polymerization by a Machine‐Learning Discovered Crystallization Model

Tian,

Treaster,

Xiong

et al. 2024

Angewandte Chemie

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Rapidly synthesizing high‐quality two‐dimensional covalent organic frameworks (2D COFs) is crucial to their practical applications. Here, we use a machine‐learning approach that overcomes the challenges associated with bottom‐up model derivation for the non‐classical 2D COF crystallization processes. The resulting model, referred to as NEgen1, establishes correlations among the induction time, nucleation rate, growth rate, bond‐forming rate constants, and common solution synthesis conditions for 2D COFs that grow by a nucleation‐elongation mechanism. The results elucidate the detailed competition between the nucleation and growth dynamics in solution, which has been inappropriately described previously by classical, empirical models with assumptions invalid for 2D COF polymerization. By understanding the dynamic processes at play, the NEgen1 model reveals a simple strategy of gradually increasing monomer addition speed for growing large 2D COF crystals. This insight enables us to rapidly synthesize large COF‐5 colloids, which could only be achieved previously by prolonged reaction times or by introducing chemical modulators. These results highlight the potential for systematically improving the crystal quality of 2D COFs, which has wide‐reaching relevance for many of the applications for which 2D COFs are speculated to be valuable.

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Sub‐Stoichiometric Covalent Organic Frameworks

Cited by 8 publications

References 65 publications

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Constructing benzothiadiazole‐based donor‒acceptor covalent organic frameworks for efficient photocatalytic H₂ evolution

Taming Two‐Dimensional Polymerization by a Machine‐Learning Discovered Crystallization Model

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Sub‐Stoichiometric Covalent Organic Frameworks

Cited by 8 publications

References 65 publications

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Highly Efficient Capture of Volatile Iodine by Conjugated Microporous Polymers Constructed Using Planar 3- and 4-Connected Organic Monomers

Constructing benzothiadiazole‐based donor‒acceptor covalent organic frameworks for efficient photocatalytic H2 evolution

Taming Two‐Dimensional Polymerization by a Machine‐Learning Discovered Crystallization Model

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Constructing benzothiadiazole‐based donor‒acceptor covalent organic frameworks for efficient photocatalytic H₂ evolution