Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollu...Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.展开更多
Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material ...Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.展开更多
Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Non...Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Nonetheless,the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation.Herein,we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets(iCONs)by tailoring the functional group via molecular engineering.Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride(TG)and aldehyde linkers.The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties,and thus reduced the dielectric confinement and the corresponding exciton binding energy(E_(b)).The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation.This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts.展开更多
In this study,a functionalized covalent-organic framework(COF)was first synthesized using porphyrin as the fabrication unit and showed an edge-curled,petal-like and well-ordered structure.The synthesized COF was then ...In this study,a functionalized covalent-organic framework(COF)was first synthesized using porphyrin as the fabrication unit and showed an edge-curled,petal-like and well-ordered structure.The synthesized COF was then introduced to prepare porous organic polymer monolithic materials(POPMs).Two composite POPM/COF monolithic materials with rod shapes,referred to as sorbent A and sorbent B,were prepared in stainless steel tubes using different monomers.Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m;/g and 80.01 m;/g,respectively.The prepared composite monoliths were used as in-tube solid-phase extraction(SPE)sorbents combined with HPLC for the on-line extraction and quantitative analytical systems.Indole alkaloids(from Catharanthus roseus G.Don and Uncaria rhynchophylla(Miq.)Miq.Ex Havil.)contained in mouse plasma were extracted and quantitatively analyzed using the online system.The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices,as well as superior selectivity for target indole alkaloids.Method validation showed that the RSD values of the repeatability(n=6)were≤3.46%,and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%-100.91%and 96.39%-103.50%for vinca alkaloids and Uncaria alkaloids,respectively.Furthermore,sorbents A and B exhibited strong reusability,with RSD values≤5.32%,which were based on the peak area of the corresponding alkaloids with more than 100 injections.These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.展开更多
Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,goo...Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and sensors.In recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of Things.Therefore,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five years.This paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis methods.Then,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced systematically.Conclusions and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.展开更多
Covalent organic frameworks(COFs)exhibiting reversible redox behaviors have been identified as promising candidates for constructing electrode materials in lithium-ion batteries(LIBs).However,their extensive applicati...Covalent organic frameworks(COFs)exhibiting reversible redox behaviors have been identified as promising candidates for constructing electrode materials in lithium-ion batteries(LIBs).However,their extensive application has been limited due to finite redox sites and poor structural stability.In this study,we design and synthesize a novel polyimide covalent organic framework(PI-COF)using the traditional solvothermal method and successfully apply it as an anode material for LIBs.The large conjugated structure of PI-COF accelerates charge transfer,while its large surface area provides more active sites,making PI-COF an attractive anode material for LIBs.Furthermore,the PI-COF anode material demonstrates high reversible specific capacity and excellent long-term cycling stability due to its COF characteristics.Specifically,the PI-COF electrodes deliver a specific capacity of 800 m Ah/g at a current density of 200 m A/g after 200 cycles,while a specific capacity of 450 m Ah/g at a current density of 1000 m A/g is sustained after 800 cycles.The outstanding lithium storage capacity,particularly the satisfactory long-term cycling stability,establishes PI-COF as a promising material for LIBs.展开更多
The universal synthesis of highly stable covalent organic frameworks(COFs)for ultra-sensitive and multi-component electrochemical detection in different scenarios remains a great challenge.Herein,a series of metalloph...The universal synthesis of highly stable covalent organic frameworks(COFs)for ultra-sensitive and multi-component electrochemical detection in different scenarios remains a great challenge.Herein,a series of metallophthalocyanine-based twodimensional(2D)dioxin(DXI)-linked metalophthalocyanine(MPc)-n DXI-COFs(M=Ni,Zn;n=1,2)are afforded in high yield(80%-96%)by a facile trace-quinoline assisted one-pot condensation of tetracarbonitrile precursors.Powder X-ray diffraction and electron microscopy investigations disclose their lamellar texture 2D network with AA stacking mode.Experiments and calculation results elucidate that the 2DXI-linked MPc-2DXI-COFs provide the stronger built-in electronic field and more electrostatic/hydrogen bonding adsorption sites than DXI-linked MPc-DXI-COFs,and the lower electrode reaction Gibbs free energy and stronger adsorption of analytes at Ni Pc than Zn Pc unit,which grants Ni Pc-2DXI-COF excellent sensing properties for various analytes including neurotransmitters,organic pollutants,and heavy metal ions,with high sensitivity and low detection limit of 0.53 to 25.66 nM.Especially in binary and ternary systems and even in real-world conditions,simultaneous multi-component detection could be achieved.展开更多
Developing new functional explosives that display high stability,good energy performance,and low sensitivity are one of the key directions of energetic materials research.In this work,two-dimensional(2D)Schiff-based e...Developing new functional explosives that display high stability,good energy performance,and low sensitivity are one of the key directions of energetic materials research.In this work,two-dimensional(2D)Schiff-based energetic covalent organic frameworks(COFs)are prepared based on triaminoguanidine salts with different anions as building blocks.Benefiting from the robust covalent bond in 2D extended polygons and strongπ-πinteractions in the eclipsed interlayers,the synthesized energetic COFs showed higher thermal stability and lower mechanical sensitivity than their precursor salts.More importantly,incorporating triaminoguanidine salts into COFs effectively increase the corrosion resistance to metal under high humidity conditions,which is due to the imine moieties in COFs functioning asπacceptors and offering strong bonding with metallic ions.This work provides a new pathway for the development of high-performance energetic materials.展开更多
Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in li...Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(LIBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in LIBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced Li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, Li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance LIBs.展开更多
Lithium-ion batteries(LIBs)have become one of the most successful energy storage systems due to their high operating voltage,high energy density,and long cycle life.However,with the widespread use of LIBs in recent de...Lithium-ion batteries(LIBs)have become one of the most successful energy storage systems due to their high operating voltage,high energy density,and long cycle life.However,with the widespread use of LIBs in recent decades,lithium resources are at risk of being exhausted.Therefore,it is necessary to find a substitute for LIBs to meet the needs of future large-scale energy storage systems.Because of their competitiveness,low cost,and high safety,aqueous rechargeable zinc-ion batteries(ARZIBs)are regarded as promising components in the post-lithium-ion-battery era.Given the tunable composition,ordered porous channels,and controllable structure of metal-organic frameworks(MOFs)and covalent organic frameworks(COFs),these frameworks are viewed as potential materials for developing high-performance ARZIBs.In this review,we focus on the recent developments in the applications of MOF-/COF-based materials in ARZIBs,including in electrode materials,anode modifications,separators,and solid electrolytes.We then focus on the critical factors and optimization techniques of MOF-/COF-based materials that affect the performance of ARZIBs.Finally,we conclude with some projections for the expansion of ARZIBs containing MOF-/COF-based materials.展开更多
Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluoresce...Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).展开更多
Covalent organic frameworks(COFs)have emerged as an interesting class of crystalline porous materials with desirable properties(such as highly ordered porosity,structural versatility,high chemical and thermal stabilit...Covalent organic frameworks(COFs)have emerged as an interesting class of crystalline porous materials with desirable properties(such as highly ordered porosity,structural versatility,high chemical and thermal stabilities,and facile surface modification)and a broad range of potential applications.This critical review is aimed at providing insight into design strategies and synthetic methodologies for COFs.Unlike previous reviews on COFs,this article also focuses on the characterization of COFs,which is important for understanding the physical and chemical properties of COFs that are essential for practical applications.Furthermore,this review highlights the applications of COFs in various fields,including catalysis,photovoltaic devices,sensors,supercapacitors,wastewater treatment,biomedicine,chromatographic and spectroscopic analyses,and gas separation and storage.Lastly,perspectives on future directions and challenges associated with COFs are provided.展开更多
Covalent organic frameworks(COFs),as a class of crystalline porous polymers,featuring designable structures,tunable frameworks,well-defined channels,and tailorable functionalities,have emerged as promising organic ele...Covalent organic frameworks(COFs),as a class of crystalline porous polymers,featuring designable structures,tunable frameworks,well-defined channels,and tailorable functionalities,have emerged as promising organic electrode materials for rechargeable metal-ion batteries in recent years.Tremendous efforts have been devoted to improving the electrochemical performance of COFs.However,although significant achievements have been made,the electrochemical behaviors of developed COFs are far away from the desirable performance for practical batteries owing to intrinsic problems,such as poor electronic conductivity,the trade-off relationship between capacity and redox potential,and unfavorable micromorphology.In this review,the recent progress in the development of COFs for rechargeable metal-ion batteries is presented,including Li,Na,K,and Zn ion batteries.Various research strategies for improving the electrochemical performance of COFs are summarized in terms of the molecular-level design and the material-level modification.Finally,the major challenges and perspectives of COFs are also discussed in the aspect of large-scale production and electrochemical performance improvements.展开更多
Heterostructures based on covalent organic frameworks(COFs)and other two-dimensional(2D)materials attract considerable attention due to their extraordinary properties and tremendous application potential.Substrate eff...Heterostructures based on covalent organic frameworks(COFs)and other two-dimensional(2D)materials attract considerable attention due to their extraordinary properties and tremendous application potential.Substrate effects play a crucial role in the integration of ultrathin COF films onto 2D materials through direct polymerization.In this study,highly ordered monolayer COFs were successfully constructed on the surfaces of highly oriented pyrolytic graphite(HOPG),hexagonal boron nitride(hBN),and molybdenum disulfide(MoS_(2)).High-resolution atomic force microscopy(HR-AFM)imaging clearly reveals the substrate orientation effect in COFs/2D materials heterostructure.Honeycomb networks formed via Schiff-base reaction and boronic acid condensation reaction can epitaxially grow in specific orientations relative to the underlying substrate lattices.This work provides direct evidence for substrate effects in the on-surface synthesis of COFs and paves the way for further investigation into the intrinsic electronic properties of monolayer COFs and the development of multifunctional hybrid devices.展开更多
In the past decades,metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)basically enjoy the coordination chemistry and covalent chemistry,respectively,and such uniqueness has become the major obstacle h...In the past decades,metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)basically enjoy the coordination chemistry and covalent chemistry,respectively,and such uniqueness has become the major obstacle hampering their further scope diversity and application multi-functionalization.Inspired from the principle of organic retrosynthesis,combining coordination bond and covalent bond together offers additional opportunities for constructing novel MOFs,COFs and MOF@COF hybrids as well as confer on them superior performances in versatile application fields.In this review,we firstly classify and summarize the recently reported synthesis strategies based on the integration of metal-ligand coordination and dynamic covalent bonds.Then,the application performances of as-constructed MOFs,COFs as well as MOF@COF hybrids are discussed and highlighted in the fields of adsorption,separation,catalysis,biosensing,energy storage and so on.Last,our personal insights of the remaining challenges and further prospects are also provided,in order to trigger much more inspirations and endeavors for this hot research field.展开更多
文摘Industrial growth in recent years led to air pollution and an increase in concentration of hazardous gases such as O<sub>3</sub> and NO. Developing new materials is important to detect and reduce air pollutants. While catalytic decomposition and zeolites are traditional ways used to reduce the amount of these gases. We need to develop and explore new promising materials. Covalent organic framework (COF) has become an attractive platform for researcher due to its extended robust covalent bonds, porosity, and crystallinity. In this study, first principal calculations were performed for gases adsorption using COFs containing nitrogen and π-bonds. Different building blocks (BBs) and linkers (LINKs/LINK1 & LINK2) were investigated by means of density functional theory (DFT) calculations with B3LYP and 3-21G basis sets to calculate the binding energies of gases @COF systems. Electrostatic potential maps (ESPM), Mulliken charges and non-covalent interaction (NCI) are used to understand the type of interactions between gas and COFs fragments. O3 was found to bind strongly with COF system in comparison with NO which could make COF a useful selective material for mixed gases environment for sensing and removal application.
基金financial aid from the National Natural Science Foundation of Guangdong Province (Grant No. 2016A030310435)Youth Scholars Fundation of South China Normal University (Grant No. 15KJ01)
文摘Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.
基金the National Natural Science Foundation of China(22072065,22178162,22222806)the Distinguished Youth Foundation of Jiangsu Province(BK20220053)the Six Talent Peaks Project in Jiangsu Province(JNHB-035)。
文摘Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Nonetheless,the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation.Herein,we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets(iCONs)by tailoring the functional group via molecular engineering.Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride(TG)and aldehyde linkers.The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties,and thus reduced the dielectric confinement and the corresponding exciton binding energy(E_(b)).The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation.This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts.
基金supported by the Natural Science Foundation of Hebei Province (Grant No.: B2020201002)the National Natural Science Foundation of China (Grant Nos.: 21974034 and 21505030)the Interdisciplinary Research Project of Natural Science of Hebei University (Grant No.: DXK201912)
文摘In this study,a functionalized covalent-organic framework(COF)was first synthesized using porphyrin as the fabrication unit and showed an edge-curled,petal-like and well-ordered structure.The synthesized COF was then introduced to prepare porous organic polymer monolithic materials(POPMs).Two composite POPM/COF monolithic materials with rod shapes,referred to as sorbent A and sorbent B,were prepared in stainless steel tubes using different monomers.Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m;/g and 80.01 m;/g,respectively.The prepared composite monoliths were used as in-tube solid-phase extraction(SPE)sorbents combined with HPLC for the on-line extraction and quantitative analytical systems.Indole alkaloids(from Catharanthus roseus G.Don and Uncaria rhynchophylla(Miq.)Miq.Ex Havil.)contained in mouse plasma were extracted and quantitatively analyzed using the online system.The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices,as well as superior selectivity for target indole alkaloids.Method validation showed that the RSD values of the repeatability(n=6)were≤3.46%,and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%-100.91%and 96.39%-103.50%for vinca alkaloids and Uncaria alkaloids,respectively.Furthermore,sorbents A and B exhibited strong reusability,with RSD values≤5.32%,which were based on the peak area of the corresponding alkaloids with more than 100 injections.These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.
基金funded by the National Natural Science Foundation of China(No.21964016)Xinjiang National Science Fund for Distinguished Young Scholars(No.2022D01E37)+1 种基金Key programs of Xinjiang Natural Science Foundation(No.2022B02051)Tianshan Innovation Team Program of Xinjiang Uygur Autonomous Region(No.2020D14038).
文摘Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and sensors.In recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of Things.Therefore,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five years.This paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis methods.Then,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced systematically.Conclusions and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.
基金supported by National Natural Science Foundation of China for Youths(Nos.21701059,22205084,51902140)Natural Science Foundation of Jiangsu Province for Youths(No.BK20170571)the financial support by Shandong Key Laboratory of Biochemical Analysis(No.SKLBA2103)。
文摘Covalent organic frameworks(COFs)exhibiting reversible redox behaviors have been identified as promising candidates for constructing electrode materials in lithium-ion batteries(LIBs).However,their extensive application has been limited due to finite redox sites and poor structural stability.In this study,we design and synthesize a novel polyimide covalent organic framework(PI-COF)using the traditional solvothermal method and successfully apply it as an anode material for LIBs.The large conjugated structure of PI-COF accelerates charge transfer,while its large surface area provides more active sites,making PI-COF an attractive anode material for LIBs.Furthermore,the PI-COF anode material demonstrates high reversible specific capacity and excellent long-term cycling stability due to its COF characteristics.Specifically,the PI-COF electrodes deliver a specific capacity of 800 m Ah/g at a current density of 200 m A/g after 200 cycles,while a specific capacity of 450 m Ah/g at a current density of 1000 m A/g is sustained after 800 cycles.The outstanding lithium storage capacity,particularly the satisfactory long-term cycling stability,establishes PI-COF as a promising material for LIBs.
基金supported by the Key Program of National Natural Science Foundation of China(22133006)the National Natural Science Foundation of China(21771192,22301314)+1 种基金the Natural Science Foundation of Shandong Province(ZR2017ZB0315)the Program for Taishan Scholar of Shandong Province(ts201712019)。
文摘The universal synthesis of highly stable covalent organic frameworks(COFs)for ultra-sensitive and multi-component electrochemical detection in different scenarios remains a great challenge.Herein,a series of metallophthalocyanine-based twodimensional(2D)dioxin(DXI)-linked metalophthalocyanine(MPc)-n DXI-COFs(M=Ni,Zn;n=1,2)are afforded in high yield(80%-96%)by a facile trace-quinoline assisted one-pot condensation of tetracarbonitrile precursors.Powder X-ray diffraction and electron microscopy investigations disclose their lamellar texture 2D network with AA stacking mode.Experiments and calculation results elucidate that the 2DXI-linked MPc-2DXI-COFs provide the stronger built-in electronic field and more electrostatic/hydrogen bonding adsorption sites than DXI-linked MPc-DXI-COFs,and the lower electrode reaction Gibbs free energy and stronger adsorption of analytes at Ni Pc than Zn Pc unit,which grants Ni Pc-2DXI-COF excellent sensing properties for various analytes including neurotransmitters,organic pollutants,and heavy metal ions,with high sensitivity and low detection limit of 0.53 to 25.66 nM.Especially in binary and ternary systems and even in real-world conditions,simultaneous multi-component detection could be achieved.
基金supported the National Natural Science Foundation of China(Nos.22175155,21825106 and 22275168)the Henan Science Fund for Excellent Young Scholars(No.212300410084)the opening project of State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)(No.KFJJ22–05 M)。
文摘Developing new functional explosives that display high stability,good energy performance,and low sensitivity are one of the key directions of energetic materials research.In this work,two-dimensional(2D)Schiff-based energetic covalent organic frameworks(COFs)are prepared based on triaminoguanidine salts with different anions as building blocks.Benefiting from the robust covalent bond in 2D extended polygons and strongπ-πinteractions in the eclipsed interlayers,the synthesized energetic COFs showed higher thermal stability and lower mechanical sensitivity than their precursor salts.More importantly,incorporating triaminoguanidine salts into COFs effectively increase the corrosion resistance to metal under high humidity conditions,which is due to the imine moieties in COFs functioning asπacceptors and offering strong bonding with metallic ions.This work provides a new pathway for the development of high-performance energetic materials.
基金supported by National Key R&D Program of China (2023YFB3608904)the National Natural Science Foundation of China (62004106, 62274097, 21835003, 62005126)+7 种基金the Natural Science Foundation of Jiangsu Province (BE2019120,BK20210601)the Foundation of Key Laboratory of Flexible Electronics of Zhejiang Province (2023FE002)Program for Jiangsu Specially-Appointed Professors (RK030STP15001)the Excellent Scientific and Technological Innovative Teams of Jiangsu Higher Education Institutions (TJ217038)the Six Talent Peaks Project of Jiangsu Province (TD-XCL-009)the 333 Project of Jiangsu Province (BRA2017402)the Project of State Key Laboratory of Organic Electronics and Information Displays,NJUPT (GZR2023-010016)Natural Science Foundation of NJUPT (NY223079)。
文摘Covalent organic frameworks(COFs) are attractive porous crystalline materials with extremely high stability, easy functionalization, and open channels, which are expected to be unique ion conductors/transporters in lithium ion batteries(LIBs). Despite recent advances, low ion conductivity and low transference number, resulting in low charging/discharging rate, low energy density, and short battery life, are the main issues that limit their direct application as solid electrolytes in LIBs. Here, we designed and synthesized a novel polyimide COF, namely, TAPA-PDI-COF, with abundant C=O groups, which has been successfully employed as high-performance solid electrolytes by doping TAPA-PDI-COF and succinonitrile(SN). Both the well-defined nanochannels of COFs and SN confined in the well-aligned channels restricted the free migration of anions, while C=O on COFs and CN groups of SN enhanced Li^(+) transport, thus achieving a high ion conductivity of 0.102 m S cm^(-1)at 80 °C and a high lithium-ion transference number of 0.855 at room temperature. According to density functional theory(DFT)calculations, Li-ion migration mainly adopted in-plane transport rather than the axial pathway, which may be due to the shorter hopping distances in the planar pathway. The results suggest an effective strategy for the design and development of all-solidstate ionic conductors for achieving high-performance LIBs.
基金supported by the National Key R&D Program of China(2019YFA0705104)GRF under the project number City U 11305218。
文摘Lithium-ion batteries(LIBs)have become one of the most successful energy storage systems due to their high operating voltage,high energy density,and long cycle life.However,with the widespread use of LIBs in recent decades,lithium resources are at risk of being exhausted.Therefore,it is necessary to find a substitute for LIBs to meet the needs of future large-scale energy storage systems.Because of their competitiveness,low cost,and high safety,aqueous rechargeable zinc-ion batteries(ARZIBs)are regarded as promising components in the post-lithium-ion-battery era.Given the tunable composition,ordered porous channels,and controllable structure of metal-organic frameworks(MOFs)and covalent organic frameworks(COFs),these frameworks are viewed as potential materials for developing high-performance ARZIBs.In this review,we focus on the recent developments in the applications of MOF-/COF-based materials in ARZIBs,including in electrode materials,anode modifications,separators,and solid electrolytes.We then focus on the critical factors and optimization techniques of MOF-/COF-based materials that affect the performance of ARZIBs.Finally,we conclude with some projections for the expansion of ARZIBs containing MOF-/COF-based materials.
基金This study was financially supported by the National Natural Science Foundation of China(Nos.22001156 and 22271178)the Innovation Capability Support Program of Shaanxi(No.2022KJXX-88)the Technology Innovation Leading Program of Shaanxi(No.2020QFY07-05).
文摘Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).
文摘Covalent organic frameworks(COFs)have emerged as an interesting class of crystalline porous materials with desirable properties(such as highly ordered porosity,structural versatility,high chemical and thermal stabilities,and facile surface modification)and a broad range of potential applications.This critical review is aimed at providing insight into design strategies and synthetic methodologies for COFs.Unlike previous reviews on COFs,this article also focuses on the characterization of COFs,which is important for understanding the physical and chemical properties of COFs that are essential for practical applications.Furthermore,this review highlights the applications of COFs in various fields,including catalysis,photovoltaic devices,sensors,supercapacitors,wastewater treatment,biomedicine,chromatographic and spectroscopic analyses,and gas separation and storage.Lastly,perspectives on future directions and challenges associated with COFs are provided.
基金National Natural Science Foundation of China,Grant/Award Number:22209155。
文摘Covalent organic frameworks(COFs),as a class of crystalline porous polymers,featuring designable structures,tunable frameworks,well-defined channels,and tailorable functionalities,have emerged as promising organic electrode materials for rechargeable metal-ion batteries in recent years.Tremendous efforts have been devoted to improving the electrochemical performance of COFs.However,although significant achievements have been made,the electrochemical behaviors of developed COFs are far away from the desirable performance for practical batteries owing to intrinsic problems,such as poor electronic conductivity,the trade-off relationship between capacity and redox potential,and unfavorable micromorphology.In this review,the recent progress in the development of COFs for rechargeable metal-ion batteries is presented,including Li,Na,K,and Zn ion batteries.Various research strategies for improving the electrochemical performance of COFs are summarized in terms of the molecular-level design and the material-level modification.Finally,the major challenges and perspectives of COFs are also discussed in the aspect of large-scale production and electrochemical performance improvements.
基金This work is supported by the National Natural Science Foundation of China(Nos.21972147 and 22132007)the Key Research Program of the Chinese Academy of Sciences(No.XDPB01)The Supercomputing Environment of the Chinese Academy of Sciences is acknowledged for providing computational resources。
文摘Heterostructures based on covalent organic frameworks(COFs)and other two-dimensional(2D)materials attract considerable attention due to their extraordinary properties and tremendous application potential.Substrate effects play a crucial role in the integration of ultrathin COF films onto 2D materials through direct polymerization.In this study,highly ordered monolayer COFs were successfully constructed on the surfaces of highly oriented pyrolytic graphite(HOPG),hexagonal boron nitride(hBN),and molybdenum disulfide(MoS_(2)).High-resolution atomic force microscopy(HR-AFM)imaging clearly reveals the substrate orientation effect in COFs/2D materials heterostructure.Honeycomb networks formed via Schiff-base reaction and boronic acid condensation reaction can epitaxially grow in specific orientations relative to the underlying substrate lattices.This work provides direct evidence for substrate effects in the on-surface synthesis of COFs and paves the way for further investigation into the intrinsic electronic properties of monolayer COFs and the development of multifunctional hybrid devices.
基金This work was supported by the National Natural Science Foundation of China(Nos.21905195 and 22103055)the Natural Science Foundation of Tianjin City(No.20JCYBJC00800)PEIYANG Young Scholars Program of Tianjin University(No.2020XRX-0023).
文摘In the past decades,metal-organic frameworks(MOFs)and covalent organic frameworks(COFs)basically enjoy the coordination chemistry and covalent chemistry,respectively,and such uniqueness has become the major obstacle hampering their further scope diversity and application multi-functionalization.Inspired from the principle of organic retrosynthesis,combining coordination bond and covalent bond together offers additional opportunities for constructing novel MOFs,COFs and MOF@COF hybrids as well as confer on them superior performances in versatile application fields.In this review,we firstly classify and summarize the recently reported synthesis strategies based on the integration of metal-ligand coordination and dynamic covalent bonds.Then,the application performances of as-constructed MOFs,COFs as well as MOF@COF hybrids are discussed and highlighted in the fields of adsorption,separation,catalysis,biosensing,energy storage and so on.Last,our personal insights of the remaining challenges and further prospects are also provided,in order to trigger much more inspirations and endeavors for this hot research field.