| 1. |
- Ai, Chenxiang, et al.
(författare)
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A knitting copolymerization Strategy to Build Porous Polytriazolium Salts for Removal of Anionic Dyes and MnO4−
- 2022
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Ingår i: Macromolecular rapid communications. - : Wiley. - 1022-1336 .- 1521-3927. ; 43:15
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Tidskriftsartikel (refereegranskat)abstract
- Although considerable efforts have been devoted to novel ionic porous networks (IPNs), the development of them in a scalable manner to tackle the issues in pollutant treatment by adsorption remains an imminent challenge. Herein, inspired by natural spider webs, a knitting copolymerization strategy is proposed to construct analogue triazolium salt-based porous networks (IPN-CSUs). It is not only convenient to incorporate the cationic motifs into the network, but easy to control over the contents of ionic pairs. The as-prepared IPN-CSUs displays a high surface area of 924 m2 g−1, a large pore volume of 1.27 cm3 g−1 and abundant ionic sites, thereby exhibiting fast adsorption rate and high adsorption capacity towards organic and inorganic pollutants. The kinetics and thermodynamics study reveal that the adsorption followed a pseudo-second-order kinetic model and Langmuir isotherm model correspondingly. Specifically, the maximum adsorption capacity of the IPN-CSUs is as high as 1.82 mg mg−1 for permanganate ions and up to 0.54 mg mg−1 for methyl orange, which stands out among the previously reported porous adsorbents so far. It is expected that the strategy reported herein can be extended to the development of other potential efficient adsorbents in water purifications.
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| 2. |
- Ai, Chenxiang, et al.
(författare)
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One-pot construction of nitrogen-rich polymeric ionic porous networks for effective CO2 capture and fixation
- 2022
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Ingår i: Polymer Chemistry. - : Royal Society of Chemistry (RSC). - 1759-9954 .- 1759-9962. ; 13:1, s. 121-129
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Tidskriftsartikel (refereegranskat)abstract
- Facile preparation of ionic porous networks (IPNs) with large and permanent porosity is highly desirable for CO2 capture and transformation but remains a challenge. Here we report a one-pot base-mediated construction of nitrogen-rich IPNs through a combination of nucleophilic substitution and quaternisation chemistry from H-imidazole. This strategy, as proven by the model reactions of 1H-imidazole or 1-methyl-1H-imidazole with cyanuric chloride, allows for fine regulation of porosity and physicochemical properties, leading to nitrogen-rich IPNs featuring abundant ionic units and radicals. The as-prepared networks, termed IPN-CSUs, efficiently capture CO2 (80.1 cc g−1 at 273 K/1 bar) with an ideal CO2/N2 selectivity of 139.7. They can also effectively catalyse the cycloaddition reaction between CO2 and epoxides with high yields of up to 99% under mild conditions (0.1 MPa, 298 K), suggesting their possible applications in the fields of both selective molecular separation and conversion. Unlike the previously known strategies generally involving single coupling chemistry, our strategy combining two coupling routes in one pot appears to be unique and potentially applicable to other building blocks.
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| 3. |
- Fan, Zhiwen, et al.
(författare)
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Porous Ionic Network/CNT Composite Separator as a Polysulfide Snaring Shield for High Performance Lithium–Sulfur Battery
- 2023
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Ingår i: Macromolecular rapid communications. - 1022-1336 .- 1521-3927. ; 44:24
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Tidskriftsartikel (refereegranskat)abstract
- Lithium–sulfur (Li–S) battery features a high theoretical energy density, but the shuttle of soluble polysulfides between the two electrodes often results in a rapid capacity decay. Herein, a straightforward electrostatic adsorption strategy based on a cross-linked polyimidazolium separator as a snaring shield of polysulfides is reported, which suppresses the undesirable migration of polysulfides to the anode. The porous ionic network (PIN)-modified carbon nanotubes (CNTs) are successfully prepared and coated onto a commercial porous polypropylene membrane in a vacuum-filtration step. The favorable affinity of the imidazolium ring toward polysulfide via the polar interaction and the electrostatic effect of ions mitigates the undesirable shuttle of polysulfides in the electrolyte, improving the Li─S battery in terms of rate performance and cycling life. Compared to the reference PIN-free CNT-coated separator, the PIN/CNT-coated one has an increased initial capacity of 1.3 folds (up to 1394.8 mAh g−1 for PIN/CNT/PP-3) at 0.1 C.
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| 4. |
- Gao, Zhu, et al.
(författare)
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Interfacial Ti-S Bond Modulated S-Scheme MOF/Covalent Triazine Framework Nanosheet Heterojunctions for Photocatalytic C-H Functionalization
- 2023
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Ingår i: Angewandte Chemie International Edition. - 1433-7851 .- 1521-3773. ; 62:27
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Tidskriftsartikel (refereegranskat)abstract
- Constructing photocatalyst systems to functionalize the inert C−H bonds has attracted extensive research interest. However, purposeful modulation of interfacial charge transfer in heterostructures remains a challenge, as it usually suffers from sluggish kinetics. Reported herein is an easy strategy to construct the heteroatom-induced interface for developing the titanium-organic frameworks (MOF-902) @ thiophene-based covalent triazine frameworks (CTF-Th) nanosheets S-scheme heterojunctions with controllable oxygen vacancies (OVs). Specifically, Ti atoms were first anchored onto the heteroatom site of CTF-Th nanosheets, and then grown into MOF-902 via an interfacial Ti−S linkage, generating OVs. Using in situ X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) calculations, the enhanced interfacial charge separation and transfer induced by moderate OVs in the pre-designed S-scheme nanosheets was validated. The heterostructures exhibited an improved efficiency in photocatalytic C3-acylation of indoles under mild conditions with a yield 8.2 times larger than pristine CTF-Th or MOF-902 and enabled an extended scope of substrates (15 examples). This performance is superior to state-of-the-art photocatalyst and can be retained, without significant loss, after 12 consecutive cycles.
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| 5. |
- Yang, Song, et al.
(författare)
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Regulating the Tautomerization in Covalent Organic Frameworks for Efficient Sacrificial Agent-Free Photocatalytic H2O2 Production
- 2024
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Ingår i: Macromolecules. - 0024-9297 .- 1520-5835. ; 57:5, s. 2039-2047
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Tidskriftsartikel (refereegranskat)abstract
- The efficiency of photocatalytic production of H2O2 is constrained by the low selectivity toward oxygen reduction, and the active sites are still under debate. Herein, analogous covalent organic framework photocatalysts were synthesized from triformylphloroglucinol (Tp) and predesigned diamines, in which a molecular engineering strategy was employed to manipulate the energy barrier for the targeted proton transfers. The tautomerization of enol-imine to keto-enamine introduced abundant alkene bonds (C═C), which serve as the primary adsorption sites and have a lower energy barrier for the reduction of the O2 reduction. DHAA-Tp COF displayed a remarkable photocatalytic H2O2 production rate of 219.5 μmol h–1 g–1 without any sacrificial reagent, which stands out among the structure-related materials. A switch from a concerted one-step 2e– to a two-step single e– process in O2 reduction was observed in TCNAQ-Tp COF, which is presumably ascribed to the suppressed tautomerization mediated by the strong electron-withdrawing cyano groups. The results demonstrate a novel concept for the photocatalytic production of H2O2 using an efficient, stable, and recyclable metal-free photocatalytic system.
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