Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with hi...Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with high transport resistance from the conventional interfacial polymerization hampers their applications.The controllable fabrication of a thin PA active layer is essential for high separation efficiency but still challenging.Herein,a covalent organic framework TpPa-1 interlayer was firstly deposited on a polyethersulfone(PES)substrate to reduce the thickness of PA active layer in interfacial polymerization.The abundant pores of TpPa-1 increase the local concentration of amine monomers by adsorbing piperazine molecules,while hydrogen bonds between hydrophilic groups of TpPa-1 and piperazine molecules slow down their diffusion rate.Arising from those synergetic effects,the PA active layer is effectively reduced from 200 nm to 120 nm.By optimizing TpPa-1 interlayer and PA active layer,the water flux of resultant membranes can reach 171.35 L·m^-2·h^-1·MPa^-1,which increased by 125.4%compared with PA/PES membranes,while the rejection rates of sodium sulfate and dyes solution remained more than 90%and 99%,respectively.Our strategy may stimulate rational design of ultrathin PA-based nanofiltration membranes with high performances.展开更多
Covalent organic frameworks(COFs)are nanoporous crystalline polymers with densely conjugated structures.This work discovers that imine-linked COFs exhibit remarkable photodegradation efficiency to azo dyes dissolved i...Covalent organic frameworks(COFs)are nanoporous crystalline polymers with densely conjugated structures.This work discovers that imine-linked COFs exhibit remarkable photodegradation efficiency to azo dyes dissolved in water.Visible light generates different types of radicals from COFs,and superoxide radicals break N=N bonds in dye molecules,resulting in 100%degradation of azo dyes within 1 h.In contrast,these dyes cannot be degraded by conventionally used photocatalysts,for example,TiO2.Importantly,the COF photocatalysts can be recovered from the dye solutions and re-used to degrade azo dyes for multiple times without loss of degradation efficiency.This work provides an efficient strategy to degrade synthetic dyes,and we expect that COFs with designable structures may use as new photocatalysts for other important applications.展开更多
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
Hybrid membranes combining the merits of both polymer matrices and fillers have drawn extensive attention. The rational design of polymer–filler interface in hybrid membranes is vitally important for reducing the occ...Hybrid membranes combining the merits of both polymer matrices and fillers have drawn extensive attention. The rational design of polymer–filler interface in hybrid membranes is vitally important for reducing the occurrence of void defects. Herein, imine-type covalent organic frameworks(COFs) were selected as the fillers due to their totally organic nature and multi-functionalities. Mussel-inspired dopamine-modified sodium alginate(Alg DA) was synthesized as the polymer matrix. The dopamine modification significantly improves the Alg DA–COF compatibility,which enhances the COF content up to 50 wt% in the hybrid membranes. The improved interfacial compatibility enhances the membrane separation selectivity. Accordingly, when utilized for dehydration of ethanol/water mixed solution(water concentration of 10 wt%), the hybrid membrane reveals high water concentration of ~98.7 wt% in permeate, and stable permeation flux larger than 1500 g·m-2·h-1. This work might afford useful insights for fabricating hybrid membranes with high separation selectivity by optimizing the polymer–filler interface.展开更多
The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).L...The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).Li-ion can transfer along the PEO chain or across the layer of TpPa-SO_(3) Li within the nanochannels,resulting in a high Li-ion conductivity of3.01×10^(-4)S/cm at 60℃.When the CPE with 0.75 wt.%TpPa-SO_(3) Li was used in the LiFePO_(4)‖Li solid-state battery,the cell delivered a stable capacity of 125 mA·h/g after 250 cycles at 0.5 C,60℃.In comparison,the cell using the CPE without TpPa-SO_(3) Li exhibited a capacity of only 118 mA·h/g.展开更多
Conjugated covalent organic frameworks(COFs)hold great promise in photocatalytic hydrogen evolution owing to their high crystallinity,large surface area,and distinct structure.However,COFs exhibit poor charge separati...Conjugated covalent organic frameworks(COFs)hold great promise in photocatalytic hydrogen evolution owing to their high crystallinity,large surface area,and distinct structure.However,COFs exhibit poor charge separation.Therefore,investigating highly effective COF-based photocatalysts is crucial.For the first time,conjugated COF/perylene diimide urea polymer(PUP)all-organic heterostructure with S-scheme interfacial charge-transfer channels was successfully developed and manufactured via in situ coupling of the two-dimensional triazine-based imine-linked COF(denoted as TATF-COF)with PUP.The optimal photocatalytic hydrogen-evolution rate of 94.5 mmol h^(-1) g^(-1) for TATF-COF/PUP is 3.5 times that of pure TATF-COF and is comparable to or even higher than that of the previously reported COF-based photocatalysts,resulting in an apparent quantum efficiency of up to 19.7%at 420 nm.The improved directional S-scheme charge transfer driven by the tuned built-in electric field and enhanced oxidation and reduction reaction rates of the photogenerated carriers contribute synergistically to the boosted photocatalytic H_(2) evolution.Experiments and theoretical studies reveal plausible H_(2) evolution and spatial S-scheme charge-separation mechanisms under visible-light irradiation.This study provides advanced methods for constructing all-organic S-scheme high-efficiency photocatalysts by the modulation of band structures.展开更多
Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,th...Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,the poor chemical stability and low electron conductivity limited their activity,and single-functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems.Herein,we have constructed novel metal organic polymers(Co-HAT-CN and Ni-HAT-CN)with dual catalytic centers(metal-N_(4) and metal-N_(2))to catalyze oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).By using different metal centers,the catalytic activity and selectivity were well-tuned.Among them,Co-HAT-CN catalyzed the ORR in a 4e^(-)pathway,with a half-wave potential of 0.8 V versus RHE,while the Ni-HAT-CN catalyze ORR in a 2e^(-)pathway with H_(2)O_(2) selectivity over 90%.Moreover,the Co-HAT-CN delivered an overpotential of 350 mV at 10 mA cm^(-2) with a corresponding Tafel slope of 24 mV dec^(-1) for OER in a 1.0 M KOH aqueous solution.The experimental results revealed that the activities toward ORR were due to the M-N_(4) sites in the frameworks,and both M-N_(4) and M-N_(2) sites contributed to the OER.This work gives us a new platform to construct bifunctional catalysts.展开更多
Inhomogeneous lithium-ion(Li^(+))deposition is one of the most crucial problems,which severely deteriorates the performance of solid-state lithium metal batteries(LMBs).Herein,we discovered that covalent organic frame...Inhomogeneous lithium-ion(Li^(+))deposition is one of the most crucial problems,which severely deteriorates the performance of solid-state lithium metal batteries(LMBs).Herein,we discovered that covalent organic framework(COF-1)with periodically arranged boron-oxygen dipole lithiophilic sites could directionally guide Li^(+)even deposition in asymmetric solid polymer electrolytes.This in situ prepared 3D cross-linked network Poly(ACMO-MBA)hybrid electrolyte simultaneously delivers outstanding ionic conductivity(1.02×10^(-3)S cm^(-1)at 30°C)and excellent mechanical property(3.5 MPa).The defined nanosized channel in COF-1 selectively conducts Li^(+)increasing Li^(+)transference number to 0.67.Besides,The COF-1 layer and Poly(ACMO-MBA)also participate in forming a boron-rich and nitrogen-rich solid electrolyte interface to further improve the interfacial stability.The Li‖Li symmetric cell exhibits remarkable cyclic stability over 1000 h.The Li‖NCM523 full cell also delivers an outstanding lifespan over 400 cycles.Moreover,the Li‖LiFePO_(4)full cell stably cycles with a capacity retention of 85%after 500 cycles.the Li‖LiFePO_(4)pouch full exhibits excellent safety performance under pierced and cut conditions.This work thereby further broadens and complements the application of COF materials in polymer electrolyte for dendrite-free and high-energy-density solid-state LMBs.展开更多
Solid polymer electrolyte is one of the most promising avenues to construct next-generation energy storage systems with high energy density,high safety,and flexibility,yet the low ionic conductivity at room temperatur...Solid polymer electrolyte is one of the most promising avenues to construct next-generation energy storage systems with high energy density,high safety,and flexibility,yet the low ionic conductivity at room temperature and poor high-voltage tolerance have limited their practical applications.To address the above issues,we design and synthesize a highly crystalline,vinyl-functionalized covalent organic framework(V-COF)rationally grafted with ether-based segments through solvent-free in situ polymerization.V-COF can afford a fast Li+conduction highway along the one-dimensional nanochannels and improve the high-voltage stability of ether-based electrolytes due to the rigid and electrochemically stable networks.The as-formed solid-state electrolyte membranes demonstrate a superior ionic conductivity of 1.1×10^(−4)S cm^(−1)at 40℃,enhanced wide electrochemical window up to 5.0 V,and high Young's modulus of 92 MPa.The Li symmetric cell demonstrates ultralong stable cycling over 600 h at a current density of 0.1 mA cm^(−2)(40℃).The assembled solid-state Li|LiFePO4 cells show a superior initial specific capacity of 136 mAh g^(−1)at 1 C(1 C=170 mA g^(−1))and a high capacity retention rate of 84%after 300 cycles.This study provides a novel and scalable approach toward high-performance solid ether-based lithium metal batteries.展开更多
Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COF...Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COFs) with intrinsically high porosity, controllable pore size, uniform pore size distribution and long-range ordered channel structure, have emerged as next-generation materials to fabricate advanced separation membranes. This feature article summarizes some latest studies in the development of pure COF membranes in our lab, including their fabrication and applications in chemical separations. Finally, current challenges facing high-performance COF separation membranes are discussed.展开更多
Gel polymer electrolytes (GPEs) with flexibility, easy processability, and low cost have been regarded as promising alternatives for conventional liquid electrolytes in next-generation sodium metal batteries (SMBs). H...Gel polymer electrolytes (GPEs) with flexibility, easy processability, and low cost have been regarded as promising alternatives for conventional liquid electrolytes in next-generation sodium metal batteries (SMBs). However, GPEs often suffer from combustion risk and inferior interfacial compatibility toward Na metal anode, which severely limit their wide commercial applications. Here, a rational design of asymmetric fireproof GPE (AFGPE) modified with a boron-contained covalent organic framework (BCOF) on one side is developed through in-situ crosslinking polymerization process. Benefiting from the unique structure and composition, the resulting AFGPE exhibits high Na+ transference number, wide electrochemical window, excellent mechanical properties and high safety. Especially, the nanoscale BCOF layer with uniform nanochannels works as ion sieve that homogenizes Na+ flux during Na plating process, while the abundant Lewis-acid B sites can strongly capture counter anions and decrease space charge layer at anode side, thus promoting the uniform Na deposition to effectively suppress dendrite growth. Consequently, the Na/AFGPE/Na symmetric cells demonstrate remarkable cycling stability for over 1200 h at 0.1 mA·cm^(-2), and the solid-state SMBs exhibit outstanding cycling properties and rate capability, delivering a high capacity retention of 96.4% under current density of 1 C for over 1000 cycles.展开更多
The development of novel porous materials have attracted significant attention owing to its possible application in several fields.In this study,we designed a novel covalent organic framework‐metal‐organic framework...The development of novel porous materials have attracted significant attention owing to its possible application in several fields.In this study,we designed a novel covalent organic framework‐metal‐organic framework(COF‐MOF)material through an in‐situ ligand self‐assembly method.The in‐situ modified ligands not only act as nucleation sites to form Ti‐MOF,but also as a channel to rapidly transfer photogenerated electrons without introducing additional chemical bonds.The photocatalytic hydrogen production rate achieved over B‐CTF‐Ti‐MOF(1:1)was 1975μmol·g^(–1)·h^(–1) with an apparent quantum efficiency of 4.76%,which is 11.8 times higher than that of the pure CTF‐1.In addition,compared with the sample prepared by separating the ligands(CTF‐1/Ti‐MOF),B‐CTF‐Ti‐MOF shows excellent activity and stability.Finally,a reasonable photocatalytic mechanism was proposed using the results of electrochemical tests and spectral analyses.This study provides a universal method for the construction of highly efficient and stable COF/MOF materials with excellent properties.展开更多
Covalent organic frameworks(COFs)are highly ordered and permanently porous organic polymers that can be classified as two-dimensional or threedimensional.Their tunable design and crystalline order endow a range of por...Covalent organic frameworks(COFs)are highly ordered and permanently porous organic polymers that can be classified as two-dimensional or threedimensional.Their tunable design and crystalline order endow a range of pore sizes,shapes,functions,and applications that differentiate them from other polymers.The COF pore sizes and shapes rely on the geometry of the monomers and dynamic covalent chemistry,while the stacking of the sheets relies on noncovalent interactions.Their tunability allows for post-modification or the incorporation of additional functional groups for the reinforcement by various noncovalent interactions.The limits of mesoporous COFs are still being investigated,with the design rules continuing to evolve.Here we report a comprehensive review of mesoporous COFs,explore strategies for large pore reinforcement,highlight structural design and features,elucidate their various functions and applications,discuss fundamental challenges faced that need to be addressed,and predict future directions.展开更多
Photocatalytic hydrogen generation from hydrogen storage media is an effective and promising approach for the green hydrogen industry as well as for achieving carbon neutrality goals.However,the lower photocatalytic e...Photocatalytic hydrogen generation from hydrogen storage media is an effective and promising approach for the green hydrogen industry as well as for achieving carbon neutrality goals.However,the lower photocatalytic efficiency due to the limited light trapping capacity,low electron transfer rate,and severe aggregation of nanoparticles caused by high surface energy seriously restricts their practical application.Herein,we constructed a series of donor–acceptor(D–A)type covalent organic frameworks to confine ultrafine bimetallic Pt-based nanoclusters for photocatalytic hydrogen generation from ammonia borane(AB)hydrolysis.Under visible light irradiation at 20℃,PtCo_(2)@covalent organic framework(COF)showed the highest photocatalytic activity with a turnover frequency(TOF)of 486 min−1.Experiments and density functional theory(DFT)calculations reveal that the high catalytic activity is mainly attributed to the strong electronic interactions between D–A type COF and ultrafine PtCo_(2)nanoclusters.Specifically,the D–A type COF can significantly enhance the light-trapping ability by fine-tuning the electron-acceptor type in the framework,and accelerate the photogenerated electron transfer from D–A type COF to PtCo_(2)nanocluster,which promotes the adsorption and activation of H_(2)O and AB molecules and accelerates hydrogen release.Furthermore,PtCo_(2)@COF also exhibited ultra-high durability due to the significantly enhanced resistance to nanocluster aggregation caused by the nanopore confinement effect of D–A type COF.We believe that this work will provide a theoretical guide for the rational design of efficient D–A COFbased catalysts for photocatalysis.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
The purification of low-grade coal-bed methane is extremely important,but challenging,due to the very similar physical properties of CH_(4)and N2.Herein,we proposed a dual polarization strategy by employing triazine a...The purification of low-grade coal-bed methane is extremely important,but challenging,due to the very similar physical properties of CH_(4)and N2.Herein,we proposed a dual polarization strategy by employing triazine and polyfluoride sites to construct polar pores in COF materials,achieving the efficient separa-tion of CH_(4)from N2.As expected,the dual polarized F-CTF-1 and F-CTF-2 exhibit higher CH_(4)adsorption capacity and CH_(4)/N_(2)selectivity than CTF-1 and CTF-2,respectively.Especially,the CH4 uptake capacity and CH_(4)/N_(2)selectivity of F-CTF-2 is 1.76 and 1.42 times than that of CTF-2.This work not only developed promising COF materials for CH4/N_(2)separation,but also provided important guidance for the separation of other adsorbates with similar properties.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
To date,significant efforts have been devoted to eliminating hazardous components to purify wastewater through the development of various nanomaterials.Covalent organic frameworks(COFs),an important branch of the poro...To date,significant efforts have been devoted to eliminating hazardous components to purify wastewater through the development of various nanomaterials.Covalent organic frameworks(COFs),an important branch of the porous crystalline family,possess the peculiarity of ultrahigh surface area,adjustable pore size,and facile functionality.Exciting studies from design fabrication to potential applications in water treatment by COF-based membranes(COMs)have emerged.This review summarizes various preparation strategies and synthesis mechanisms for COMs,including layer-by-layer stacking,in situ growth,interfacial polymerization,and electrochemical synthesis,and briefly describes the advanced characterization techniques for COMs.Moreover,the application of COMs in heavy metal removal,dye separation,purification of radionuclides,pollutant detection,sea water desalination,and so on,is described and discussed.Finally,the perspectives on future opportunities for designing COMs in water purification have been proposed.展开更多
基金supported by the Open Project Program of State Key Laboratory of Petroleum Pollution Control(Grant No.PPC2017014)CNPC Research Institute of Safety and Environmental Technology。
文摘Polyamide(PA)-based thin-film composite membranes exhibit enormous potential in water purification,owing to their facile fabrication,decent performance and desirable stability.However,the thick PA active layer with high transport resistance from the conventional interfacial polymerization hampers their applications.The controllable fabrication of a thin PA active layer is essential for high separation efficiency but still challenging.Herein,a covalent organic framework TpPa-1 interlayer was firstly deposited on a polyethersulfone(PES)substrate to reduce the thickness of PA active layer in interfacial polymerization.The abundant pores of TpPa-1 increase the local concentration of amine monomers by adsorbing piperazine molecules,while hydrogen bonds between hydrophilic groups of TpPa-1 and piperazine molecules slow down their diffusion rate.Arising from those synergetic effects,the PA active layer is effectively reduced from 200 nm to 120 nm.By optimizing TpPa-1 interlayer and PA active layer,the water flux of resultant membranes can reach 171.35 L·m^-2·h^-1·MPa^-1,which increased by 125.4%compared with PA/PES membranes,while the rejection rates of sodium sulfate and dyes solution remained more than 90%and 99%,respectively.Our strategy may stimulate rational design of ultrathin PA-based nanofiltration membranes with high performances.
基金financially supported by the National Science Fund for Distinguished Young Scholars (21825803)the Program of Excellent Innovation Teams of Jiangsu Higher Education Institutions and the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Covalent organic frameworks(COFs)are nanoporous crystalline polymers with densely conjugated structures.This work discovers that imine-linked COFs exhibit remarkable photodegradation efficiency to azo dyes dissolved in water.Visible light generates different types of radicals from COFs,and superoxide radicals break N=N bonds in dye molecules,resulting in 100%degradation of azo dyes within 1 h.In contrast,these dyes cannot be degraded by conventionally used photocatalysts,for example,TiO2.Importantly,the COF photocatalysts can be recovered from the dye solutions and re-used to degrade azo dyes for multiple times without loss of degradation efficiency.This work provides an efficient strategy to degrade synthetic dyes,and we expect that COFs with designable structures may use as new photocatalysts for other important applications.
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Supported by the National Natural Science Foundation of China(21621004,21490583,21878215,21878216)the Program of Introducing Talents of Discipline to Universities(B06006)the State Key Laboratory of Organic–Inorganic Composites(oic-201801003).
文摘Hybrid membranes combining the merits of both polymer matrices and fillers have drawn extensive attention. The rational design of polymer–filler interface in hybrid membranes is vitally important for reducing the occurrence of void defects. Herein, imine-type covalent organic frameworks(COFs) were selected as the fillers due to their totally organic nature and multi-functionalities. Mussel-inspired dopamine-modified sodium alginate(Alg DA) was synthesized as the polymer matrix. The dopamine modification significantly improves the Alg DA–COF compatibility,which enhances the COF content up to 50 wt% in the hybrid membranes. The improved interfacial compatibility enhances the membrane separation selectivity. Accordingly, when utilized for dehydration of ethanol/water mixed solution(water concentration of 10 wt%), the hybrid membrane reveals high water concentration of ~98.7 wt% in permeate, and stable permeation flux larger than 1500 g·m-2·h-1. This work might afford useful insights for fabricating hybrid membranes with high separation selectivity by optimizing the polymer–filler interface.
基金supported by the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)the National Natural Science Foundation of China(Nos.21878216,22005215)+1 种基金Hebei Province Innovation Ability Promotion Project(No.20312201D)the National Key Research and Development Program of China(No.2019YFE0118800)。
文摘The lithiated covalent organic framework(named TpPa-SO_(3) Li),which was prepared by a mild chemical lithiation strategy,was introduced in poly(ethylene oxide)(PEO)to produce the composite polymer electrolytes(CPEs).Li-ion can transfer along the PEO chain or across the layer of TpPa-SO_(3) Li within the nanochannels,resulting in a high Li-ion conductivity of3.01×10^(-4)S/cm at 60℃.When the CPE with 0.75 wt.%TpPa-SO_(3) Li was used in the LiFePO_(4)‖Li solid-state battery,the cell delivered a stable capacity of 125 mA·h/g after 250 cycles at 0.5 C,60℃.In comparison,the cell using the CPE without TpPa-SO_(3) Li exhibited a capacity of only 118 mA·h/g.
文摘Conjugated covalent organic frameworks(COFs)hold great promise in photocatalytic hydrogen evolution owing to their high crystallinity,large surface area,and distinct structure.However,COFs exhibit poor charge separation.Therefore,investigating highly effective COF-based photocatalysts is crucial.For the first time,conjugated COF/perylene diimide urea polymer(PUP)all-organic heterostructure with S-scheme interfacial charge-transfer channels was successfully developed and manufactured via in situ coupling of the two-dimensional triazine-based imine-linked COF(denoted as TATF-COF)with PUP.The optimal photocatalytic hydrogen-evolution rate of 94.5 mmol h^(-1) g^(-1) for TATF-COF/PUP is 3.5 times that of pure TATF-COF and is comparable to or even higher than that of the previously reported COF-based photocatalysts,resulting in an apparent quantum efficiency of up to 19.7%at 420 nm.The improved directional S-scheme charge transfer driven by the tuned built-in electric field and enhanced oxidation and reduction reaction rates of the photogenerated carriers contribute synergistically to the boosted photocatalytic H_(2) evolution.Experiments and theoretical studies reveal plausible H_(2) evolution and spatial S-scheme charge-separation mechanisms under visible-light irradiation.This study provides advanced methods for constructing all-organic S-scheme high-efficiency photocatalysts by the modulation of band structures.
基金support from the Natural Science Foundation of Shanghai (20ZR1464000)G.Zeng acknowledges the support from the National Natural Science Foundation of China (21878322,22075309)the Science and Technology Commission of Shanghai Municipality (19ZR1479200,22ZR1470100)。
文摘Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,the poor chemical stability and low electron conductivity limited their activity,and single-functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems.Herein,we have constructed novel metal organic polymers(Co-HAT-CN and Ni-HAT-CN)with dual catalytic centers(metal-N_(4) and metal-N_(2))to catalyze oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).By using different metal centers,the catalytic activity and selectivity were well-tuned.Among them,Co-HAT-CN catalyzed the ORR in a 4e^(-)pathway,with a half-wave potential of 0.8 V versus RHE,while the Ni-HAT-CN catalyze ORR in a 2e^(-)pathway with H_(2)O_(2) selectivity over 90%.Moreover,the Co-HAT-CN delivered an overpotential of 350 mV at 10 mA cm^(-2) with a corresponding Tafel slope of 24 mV dec^(-1) for OER in a 1.0 M KOH aqueous solution.The experimental results revealed that the activities toward ORR were due to the M-N_(4) sites in the frameworks,and both M-N_(4) and M-N_(2) sites contributed to the OER.This work gives us a new platform to construct bifunctional catalysts.
基金financially supported by the National Natural Science Foundation of China(No.52273081,No.22278329)Young Talent Support Plan of Xi’an Jiaotong University+2 种基金Natural Science Basic Research Program of Shaanxi(No.2022TD-27,No.2020-JC-09)the financial support from Swedish Research Council Grant(2021-05839)the“Young Talent Support Plan”of Xi’an Jiaotong University
文摘Inhomogeneous lithium-ion(Li^(+))deposition is one of the most crucial problems,which severely deteriorates the performance of solid-state lithium metal batteries(LMBs).Herein,we discovered that covalent organic framework(COF-1)with periodically arranged boron-oxygen dipole lithiophilic sites could directionally guide Li^(+)even deposition in asymmetric solid polymer electrolytes.This in situ prepared 3D cross-linked network Poly(ACMO-MBA)hybrid electrolyte simultaneously delivers outstanding ionic conductivity(1.02×10^(-3)S cm^(-1)at 30°C)and excellent mechanical property(3.5 MPa).The defined nanosized channel in COF-1 selectively conducts Li^(+)increasing Li^(+)transference number to 0.67.Besides,The COF-1 layer and Poly(ACMO-MBA)also participate in forming a boron-rich and nitrogen-rich solid electrolyte interface to further improve the interfacial stability.The Li‖Li symmetric cell exhibits remarkable cyclic stability over 1000 h.The Li‖NCM523 full cell also delivers an outstanding lifespan over 400 cycles.Moreover,the Li‖LiFePO_(4)full cell stably cycles with a capacity retention of 85%after 500 cycles.the Li‖LiFePO_(4)pouch full exhibits excellent safety performance under pierced and cut conditions.This work thereby further broadens and complements the application of COF materials in polymer electrolyte for dendrite-free and high-energy-density solid-state LMBs.
基金Shanghai Science and Technology Commission,Grant/Award Numbers:21010503100,20ZR1438400,22ZR1443900National Natural Science Foundation of China,Grant/Award Numbers:51971146,5191147,21905174+2 种基金Shanghai Outstanding Academic Leaders PlanInnovation Program of Shanghai Municipal Education Commission,Grant/Award Number:2019-01-07-00-07-E00015Shanghai Rising-Star Program,Grant/Award Numbers:20QA1407100,21QA1406500。
文摘Solid polymer electrolyte is one of the most promising avenues to construct next-generation energy storage systems with high energy density,high safety,and flexibility,yet the low ionic conductivity at room temperature and poor high-voltage tolerance have limited their practical applications.To address the above issues,we design and synthesize a highly crystalline,vinyl-functionalized covalent organic framework(V-COF)rationally grafted with ether-based segments through solvent-free in situ polymerization.V-COF can afford a fast Li+conduction highway along the one-dimensional nanochannels and improve the high-voltage stability of ether-based electrolytes due to the rigid and electrochemically stable networks.The as-formed solid-state electrolyte membranes demonstrate a superior ionic conductivity of 1.1×10^(−4)S cm^(−1)at 40℃,enhanced wide electrochemical window up to 5.0 V,and high Young's modulus of 92 MPa.The Li symmetric cell demonstrates ultralong stable cycling over 600 h at a current density of 0.1 mA cm^(−2)(40℃).The assembled solid-state Li|LiFePO4 cells show a superior initial specific capacity of 136 mAh g^(−1)at 1 C(1 C=170 mA g^(−1))and a high capacity retention rate of 84%after 300 cycles.This study provides a novel and scalable approach toward high-performance solid ether-based lithium metal batteries.
基金financially supported by the National Natural Science Foundation of China (Nos. 22378300 and 21878215)National Key Research and Development Program of China (No.2022YFB3805202)+3 种基金Key Research and Development Program of Zhejiang Province (No. 2021C03173)Ningbo Key Research and Development Project (No. 2022Z121)Program of Introducing Talents of Discipline to Universities (No.BP0618007)Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COFs) with intrinsically high porosity, controllable pore size, uniform pore size distribution and long-range ordered channel structure, have emerged as next-generation materials to fabricate advanced separation membranes. This feature article summarizes some latest studies in the development of pure COF membranes in our lab, including their fabrication and applications in chemical separations. Finally, current challenges facing high-performance COF separation membranes are discussed.
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20210474)the National Natural Science Foundation of China(NSFC,No.52203261)the project of research on the industrial application of “controllable synthesis of nanocarbon-based polymer composites and their application in new energy”(No.CJGJZD20210408092400002)。
文摘Gel polymer electrolytes (GPEs) with flexibility, easy processability, and low cost have been regarded as promising alternatives for conventional liquid electrolytes in next-generation sodium metal batteries (SMBs). However, GPEs often suffer from combustion risk and inferior interfacial compatibility toward Na metal anode, which severely limit their wide commercial applications. Here, a rational design of asymmetric fireproof GPE (AFGPE) modified with a boron-contained covalent organic framework (BCOF) on one side is developed through in-situ crosslinking polymerization process. Benefiting from the unique structure and composition, the resulting AFGPE exhibits high Na+ transference number, wide electrochemical window, excellent mechanical properties and high safety. Especially, the nanoscale BCOF layer with uniform nanochannels works as ion sieve that homogenizes Na+ flux during Na plating process, while the abundant Lewis-acid B sites can strongly capture counter anions and decrease space charge layer at anode side, thus promoting the uniform Na deposition to effectively suppress dendrite growth. Consequently, the Na/AFGPE/Na symmetric cells demonstrate remarkable cycling stability for over 1200 h at 0.1 mA·cm^(-2), and the solid-state SMBs exhibit outstanding cycling properties and rate capability, delivering a high capacity retention of 96.4% under current density of 1 C for over 1000 cycles.
文摘The development of novel porous materials have attracted significant attention owing to its possible application in several fields.In this study,we designed a novel covalent organic framework‐metal‐organic framework(COF‐MOF)material through an in‐situ ligand self‐assembly method.The in‐situ modified ligands not only act as nucleation sites to form Ti‐MOF,but also as a channel to rapidly transfer photogenerated electrons without introducing additional chemical bonds.The photocatalytic hydrogen production rate achieved over B‐CTF‐Ti‐MOF(1:1)was 1975μmol·g^(–1)·h^(–1) with an apparent quantum efficiency of 4.76%,which is 11.8 times higher than that of the pure CTF‐1.In addition,compared with the sample prepared by separating the ligands(CTF‐1/Ti‐MOF),B‐CTF‐Ti‐MOF shows excellent activity and stability.Finally,a reasonable photocatalytic mechanism was proposed using the results of electrochemical tests and spectral analyses.This study provides a universal method for the construction of highly efficient and stable COF/MOF materials with excellent properties.
基金the University of Texas(UT),Dallas and the American Chemical Society Petroleum Research Fund(PRF#61360-ND10).
文摘Covalent organic frameworks(COFs)are highly ordered and permanently porous organic polymers that can be classified as two-dimensional or threedimensional.Their tunable design and crystalline order endow a range of pore sizes,shapes,functions,and applications that differentiate them from other polymers.The COF pore sizes and shapes rely on the geometry of the monomers and dynamic covalent chemistry,while the stacking of the sheets relies on noncovalent interactions.Their tunability allows for post-modification or the incorporation of additional functional groups for the reinforcement by various noncovalent interactions.The limits of mesoporous COFs are still being investigated,with the design rules continuing to evolve.Here we report a comprehensive review of mesoporous COFs,explore strategies for large pore reinforcement,highlight structural design and features,elucidate their various functions and applications,discuss fundamental challenges faced that need to be addressed,and predict future directions.
基金supported by the National Natural Science Foundation of China(No.22178266)the Fundamental Research Funds for the Central Universities,and China Postdoctoral Science Foundation(Nos.2021M691754 and 2023T160369).
文摘Photocatalytic hydrogen generation from hydrogen storage media is an effective and promising approach for the green hydrogen industry as well as for achieving carbon neutrality goals.However,the lower photocatalytic efficiency due to the limited light trapping capacity,low electron transfer rate,and severe aggregation of nanoparticles caused by high surface energy seriously restricts their practical application.Herein,we constructed a series of donor–acceptor(D–A)type covalent organic frameworks to confine ultrafine bimetallic Pt-based nanoclusters for photocatalytic hydrogen generation from ammonia borane(AB)hydrolysis.Under visible light irradiation at 20℃,PtCo_(2)@covalent organic framework(COF)showed the highest photocatalytic activity with a turnover frequency(TOF)of 486 min−1.Experiments and density functional theory(DFT)calculations reveal that the high catalytic activity is mainly attributed to the strong electronic interactions between D–A type COF and ultrafine PtCo_(2)nanoclusters.Specifically,the D–A type COF can significantly enhance the light-trapping ability by fine-tuning the electron-acceptor type in the framework,and accelerate the photogenerated electron transfer from D–A type COF to PtCo_(2)nanocluster,which promotes the adsorption and activation of H_(2)O and AB molecules and accelerates hydrogen release.Furthermore,PtCo_(2)@COF also exhibited ultra-high durability due to the significantly enhanced resistance to nanocluster aggregation caused by the nanopore confinement effect of D–A type COF.We believe that this work will provide a theoretical guide for the rational design of efficient D–A COFbased catalysts for photocatalysis.
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 National Key R&D Program of China(No.2022YFA1503300)National Natural Science Foundation of China(Nos.21978138,22035003)+1 种基金the Fundamental Research Funds for the Central Universities(Nankai University)the Haihe Laboratory of Sustainable Chemical Transformations(No.YYJC202101).
文摘The purification of low-grade coal-bed methane is extremely important,but challenging,due to the very similar physical properties of CH_(4)and N2.Herein,we proposed a dual polarization strategy by employing triazine and polyfluoride sites to construct polar pores in COF materials,achieving the efficient separa-tion of CH_(4)from N2.As expected,the dual polarized F-CTF-1 and F-CTF-2 exhibit higher CH_(4)adsorption capacity and CH_(4)/N_(2)selectivity than CTF-1 and CTF-2,respectively.Especially,the CH4 uptake capacity and CH_(4)/N_(2)selectivity of F-CTF-2 is 1.76 and 1.42 times than that of CTF-2.This work not only developed promising COF materials for CH4/N_(2)separation,but also provided important guidance for the separation of other adsorbates with similar properties.
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+).
基金supported by National Key Research and Development Program of China(2018YFC1900105)National Natural Science Foundation of China(22276054)Beijing Outstanding Young Scientist Program.
文摘To date,significant efforts have been devoted to eliminating hazardous components to purify wastewater through the development of various nanomaterials.Covalent organic frameworks(COFs),an important branch of the porous crystalline family,possess the peculiarity of ultrahigh surface area,adjustable pore size,and facile functionality.Exciting studies from design fabrication to potential applications in water treatment by COF-based membranes(COMs)have emerged.This review summarizes various preparation strategies and synthesis mechanisms for COMs,including layer-by-layer stacking,in situ growth,interfacial polymerization,and electrochemical synthesis,and briefly describes the advanced characterization techniques for COMs.Moreover,the application of COMs in heavy metal removal,dye separation,purification of radionuclides,pollutant detection,sea water desalination,and so on,is described and discussed.Finally,the perspectives on future opportunities for designing COMs in water purification have been proposed.