Covalent Organic Frameworks: Design, Synthesis, and Functions

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(16), P. 8814 - 8933

Published: Jan. 22, 2020

Covalent organic frameworks (COFs) are a class of crystalline porous polymers with permanent porosity and highly ordered structures. Unlike other polymers, significant feature COFs is that they structurally predesignable, synthetically controllable, functionally manageable. In principle, the topological design diagram offers geometric guidance for structural tiling extended polygons, polycondensation reactions provide synthetic ways to construct predesigned primary high-order Progress over past decade in chemistry these two aspects undoubtedly established base COF field. By virtue availability units diversity topologies linkages, have emerged as new field materials offer powerful molecular platform complex tailor-made functional development. Here we target comprehensive review field, historic overview survey advances topology reactions, illustrate features diversities, scrutinize development potential various functions through elucidating structure–function correlations based on interactions photons, electrons, holes, spins, ions, molecules, discuss key fundamental challenging issues need be addressed, predict future directions from chemistry, physics, perspectives.

Language: Английский

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Covalent organic framework photocatalysts: structures and applications

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(12), P. 4135 - 4165

Published: Jan. 1, 2020

In the light of increasing energy demand and environmental pollution, it is urgently required to find a clean renewable source. these years, photocatalysis that uses solar for either fuel production, such as hydrogen evolution hydrocarbon or pollutant degradation, has shown great potential achieve this goal. Among various photocatalysts, covalent organic frameworks (COFs) are very attractive due their excellent structural regularity, robust framework, inherent porosity good activity. Thus, many studies have been carried out investigate photocatalytic performance COFs COF-based photocatalysts. critical review, recent progress advances COF photocatalysts thoroughly presented. Furthermore, diverse linkers between building blocks boron-containing connections nitrogen-containing summarised compared. The morphologies several commonly used strategies pertaining activity also discussed. Following this, applications detailed including evolution, CO2 conversion degradation contaminants. Finally, summary perspective on opportunities challenges future development given.

Language: Английский

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Covalent organic frameworks: an ideal platform for designing ordered materials and advanced applications

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 50(1), P. 120 - 242

Published: Dec. 7, 2020

Covalent organic frameworks offer a molecular platform for integrating units into periodically ordered yet extended 2D and 3D polymers to create topologically well-defined polygonal lattices built-in discrete micropores and/or mesopores.

Language: Английский

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Regenerable and stable sp2 carbon-conjugated covalent organic frameworks for selective detection and extraction of uranium

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Jan. 23, 2020

Abstract Uranium is a key element in the nuclear industry, but its unintended leakage has caused health and environmental concerns. Here we report sp 2 carbon-conjugated fluorescent covalent organic framework (COF) named TFPT-BTAN-AO with excellent chemical, thermal radiation stability synthesized by integrating triazine-based building blocks amidoxime-substituted linkers. shows an exceptional UO 2+ adsorption capacity of 427 mg g −1 attributable to abundant selective uranium-binding groups on highly accessible pore walls open 1D channels. In addition, it ultra-fast response time (2 s) ultra-low detection limit 6.7 nM suitable for on-site real-time monitoring , allowing not only extraction also quality extracted water. This study demonstrates great potential COFs radionuclide extraction. By rational designing target ligands, this strategy can be extended other contaminants.

Language: Английский

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A Scalable General Synthetic Approach toward Ultrathin Imine-Linked Two-Dimensional Covalent Organic Framework Nanosheets for Photocatalytic CO₂ Reduction

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(43), P. 17431 - 17440

Published: Oct. 13, 2019

Fabricating ultrathin two-dimensional (2D) covalent organic framework (COF) nanosheets (NSs) in large scale and high yield still remains a great challenge. This limits the exploration of unique functionalities wide range application potentials such materials. Herein, we develop scalable general bottom-up approach to facilely synthesize (<2.1 nm) imine-based 2D COF NSs (including COF-366 NSs, COF-367 COF-367-Co TAPB-PDA TAPB-BPDA NSs) (>100 mg) (>55%), via an imine-exchange synthesis strategy through adding excess amounts 2,4,6-trimethylbenzaldehyde into reaction system under solvothermal conditions. Impressively, visualization periodic pore lattice for by scanning tunneling microscope (STM) clearly discloses nature. In particular, isolated are subject heterogeneous photocatalyst CO2-to-CO conversion, showing excellent efficiency with CO production rate as 10 162 μmol g-1 h-1 selectivity ca. 78% aqueous media visible-light irradiation, far superior corresponding bulk materials comparable thus reported state-of-the-art driven heterocatalysts.

Language: Английский

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Regulating Photocatalysis by Spin-State Manipulation of Cobalt in Covalent Organic Frameworks

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(39), P. 16723 - 16731

Published: Sept. 7, 2020

While catalysis is highly dependent on the electronic structure of catalyst, understanding catalytic performance affected by electron spin regulation remains challenging and rare. Herein, we have developed a facile strategy to manipulation cobalt state over covalent organic frameworks (COFs), COF-367-Co, simply changing oxidation Co centered in porphyrin. Density functional theory (DFT) calculations together with experimental results confirm that CoII CoIII are embedded COF-367 S = 1/2 0 ground states, respectively. Remarkably, photocatalytic CO2 reduction indicate COF-367-CoIII exhibits favorable activity significantly enhanced selectivity HCOOH, accordingly much reduced CO CH4, sharp contrast COF-367-CoII. The highlight spin-state transition greatly regulates performance. Theoretical further disclose presence COF-367-Co preferable formation HCOOH but detrimental its conversion, which clearly accounts for distinctly different photocatalysis To best our knowledge, this first report regulating COFs.

Language: Английский

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Semiconducting 2D Triazine-Cored Covalent Organic Frameworks with Unsubstituted Olefin Linkages

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(36), P. 14272 - 14279

Published: Aug. 20, 2019

Establishing an sp2-carbon-bonding pattern is one of the efficient accesses to various organic semiconducting materials. However, less-reversible carbon-carbon bond formation makes it still challenging spatially construct a well-defined framework with π-extended two-dimensional (2D) structure through solution process. Here, Knoevenagel condensation approach synthesize two new 2D covalent frameworks (COFs) connected by unsubstituted double linkages activating methyl carbons 2,4,6-trimethyl-1,3,5-triazine monomer presented. The resulting sp2-carbon-linked triazine-cored sheets are vertically stacked into high-crystalline honeycomb-like structures, endowing this kind COF extended π-delocalization, tunable energy levels, as well high surface areas, regular open channels, and chemical stabilities. On other hand, their microfibrillar morphologies allow for facile manipulation thin films photoelectrodes without additive. Accordingly, such kinds COF-based exhibit photocurrents up ∼45 μA cm-2 at 0.2 V vs RHE rapid charge transfer rates, in comparison imine-linked photoelectrodes. In addition, both COFs applicable conducting photocatalytic hydrogen generation from water splitting visible-light irradiation.

Language: Английский

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Rational design of isostructural 2D porphyrin-based covalent organic frameworks for tunable photocatalytic hydrogen evolution

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: March 1, 2021

Abstract Covalent organic frameworks have recently gained increasing attention in photocatalytic hydrogen generation from water. However, their structure-property-activity relationship, which should be beneficial for the structural design, is still far-away explored. Herein, we report designed synthesis of four isostructural porphyrinic two-dimensional covalent (MPor-DETH-COF, M = H 2 , Co, Ni, Zn) and activity generation. Our results clearly show that all adopt AA stacking structures, with high crystallinity large surface area. Interestingly, incorporation different transition metals into porphyrin rings can rationally tune evolution rate corresponding frameworks, order CoPor-DETH-COF < Por-DETH-COF NiPor-DETH-COF ZnPor-DETH-COF. Based on detailed experiments calculations, this tunable performance mainly explained by tailored charge-carrier dynamics via molecular engineering. This study not only represents a simple effective way efficient tuning activities at level, but also provides valuable insight structure design better photocatalysis.

Language: Английский

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Covalent organic frameworks for photocatalytic applications

Applied Catalysis B Environment and Energy, Journal Year: 2020, Volume and Issue: 276, P. 119174 - 119174

Published: May 28, 2020

Language: Английский

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Efficient electron transmission in covalent organic framework nanosheets for highly active electrocatalytic carbon dioxide reduction

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: Jan. 24, 2020

Abstract Efficient conversion of carbon dioxide (CO 2 ) into value-added products is essential for clean energy research. Design stable, selective, and powerful electrocatalysts CO reduction reaction RR) highly desirable yet largely unmet. In this work, a series metalloporphyrin-tetrathiafulvalene based covalent organic frameworks (M-TTCOFs) are designed. Tetrathiafulvalene, serving as electron donator or carrier, can construct an oriented transmission pathway with metalloporphyrin. Thus-obtained M-TTCOFs serve high FE (91.3%, −0.7 V) possess cycling stability (>40 h). addition, after exfoliation, the value Co-TTCOF nanosheets (~5 nm) higher than 90% in wide potential range from −0.6 to −0.9 V maximum reach up almost 100% (99.7%, −0.8 V). The electrocatalytic RR mechanisms discussed revealed by density functional theory calculations. This work paves new way exploring porous crystalline materials RR.

Language: Английский

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