CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organ...CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.展开更多
The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, [CuCl]20[Cp*FeP5]12[Cu-(CH3CN) + 2Cl?]5 has been studied by a density functional approach. Geometrical optimiz...The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, [CuCl]20[Cp*FeP5]12[Cu-(CH3CN) + 2Cl?]5 has been studied by a density functional approach. Geometrical optimization of the three basic structural units of the molecule is performed with Amsterdam Density Functional Program. The results are in agreement with the experiment. Localized MO’s obtained by Boys-Foster method give a clear picture of the chemical bonding in this molecule. The reason why CuCl can react with Cp*FeP5 in solvent CH3CN to form the fullerene-like molecule is explained in terms of the soft-hard Lewis acid base theory and a new concept of covalence.展开更多
1 Introduction Generally beryllium is considered as a bivalent element, which implies that its oxidation state is+2. However, almost all compounds of beryllium are covalent ones with partial ionic character, even thos...1 Introduction Generally beryllium is considered as a bivalent element, which implies that its oxidation state is+2. However, almost all compounds of beryllium are covalent ones with partial ionic character, even those formed with the most electronegative elements F and O, e. g. BeF<sub>2</sub> and BeO. The coordination numbers of beryllium in its compounds are 2, 3 and 4. Some people consider the coordination number as covalence, but we think that they are展开更多
High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carb...High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.展开更多
In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry bet...In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.展开更多
Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limi...Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limited by challenges including instability and off-target effects.To overcome these limitations in kinase inhibitor A5,we devised a pH-responsive prodrug strategy by masking its reactive aldehyde group with an acid-labile hydrazone linkage and enhancing intracellular delivery through conjugation with FK506.The optimized prodrug demonstrated robust antitumor efficacy in K562 tumor-bearing mice.Furthermore,the incorporation of the photosensitizer chlorin e6(Ce6)led to the formation of self-assembled nanoparticles(AKNP),which not only improved physiological stability and prolonged tumor retention but also enabled light-triggered release of A5 in conjunction with photodynamic therapy(PDT).Our study thus presents a promising prodrug self-assembly strategy that combines the on-demand release of a novel lysine-targeting,reversible covalent kinase inhibitor with PDT in clinical cancer therapy.展开更多
Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystall...Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.展开更多
Responsive colorimetric materials exhibit significant potential for application in fields such as smart food packaging and wound monitoring.The functional integration of pH-indicators with material carriers enables br...Responsive colorimetric materials exhibit significant potential for application in fields such as smart food packaging and wound monitoring.The functional integration of pH-indicators with material carriers enables breakthrough applications in nontraditional domains.In this study,we developed a novel material covalently grafted with a pH indicator that exhibited naked-eye pH-responsive color shifts.The covalent grafting of pH-responsive bromothymol blue onto carboxymethyl cellulose(CMC)was confirmed using advanced characterization techniques,including Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy.The pH-sensitive chromophore was covalently immobilized onto the CMC matrix through esterification,thereby establishing firm chemical conjugation.Moreover,a superior color-changing performance was achieved within several minutes in response to different pH values.The reusability and stability of this material offer distinct advantages over single-use pH test strips.pH-responsive colorimetric materials hold promise for efficient,noninvasive monitoring in intelligent packaging(food freshness),medical diagnostics(wound status,infections),biosensing,and environmental applications.展开更多
This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were sy...This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were synthesized and characterized.CTF-DCB-1,with superior crystallinity,demonstrated highselectivity GC separation of benzene isomers as well as styrene/phenylacetylene mixtures,while CTFDCB-2 and CTF-DCB-3 exhibited lower crystallinity and worse separation performance.Thermodynamic and kinetic tests showed that CTF-DCB-1 had the worst thermodynamic adsorption but low diffusion mass transfer resistance,which resulted in the best separation.Therefore,optimizing the crystallinity of COFs is necessary for balancing the kinetic diffusion and thermodynamic interactions towards the analytes,achieving high-performance GC stationary phases.展开更多
As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term...As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term uranium supply but is challenged by ultra-low uranium concentrations and ion interference.To overcome these issues,we design three diketopyrrolopyrrole-based covalent organic frameworks(COFs)via a synergisticπ-extended lock and carboxyl-functionalized anchor molecular engineering strategy.Among them,TPy-DPP-COF features a covalently lockedπ-conjugated structure that enhances planarity,optimizes energy alignment,and minimizes exciton binding energy,thereby promoting charge transfer and suppressing recombination.Concurrently,carboxyl groups enable uranyl-specific coordination and create local electric fields to facilitate charge separation.These features contribute to the outstanding performance of TPy-DPP-COF,which achieves a high uranium adsorption capacity of 16.33 mg g−1 in natural seawater under irradiation,with only 29.3%capacity loss after 10 cycles,surpassing industrial benchmarks.Density functional theory(DFT)calculations and experimental studies reveal a synergistic photocatalysis-adsorption pathway,with DPP units acting as active sites for uranium reduction.This work highlights a molecular design strategy for developing efficient COF-based photocatalysts for practical marine uranium recovery.展开更多
Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolec...Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolecules.In recent years,significant progresses in interlocked covalent organic cages have been witnessed.Different topological structures have been fabricated via various non-template induced methods,and diverse weak interactions are demonstrated to play critical roles in guiding the formation of interlocked structures.Therefore,this article systematically summarizes the recent advances in interlocked covalent organic cages,especially their design,synthesis,and self-assembly properties.Depending on different types of chemical reactions,irreversible and reversible reactions are separately introduced.In each section,proper monomer selection,critical topology design,key driving forces as well as detailed interlocked mechanisms for the formation of interlocked structures,and their self-assembly behaviors in single crystals are discussed detailedly.Finally,the challenge and future development of interlocked covalent organic cages are briefly prospected.展开更多
Supramolecular catalysis uses noncovalent interactions,such as hydrogen bonding,π-π stacking,and host-vip recognition,to control reactivity and selectivity in chemical reactions [1,2].Unlike traditional covalent c...Supramolecular catalysis uses noncovalent interactions,such as hydrogen bonding,π-π stacking,and host-vip recognition,to control reactivity and selectivity in chemical reactions [1,2].Unlike traditional covalent catalysis,supramolecular systems can create dynamic and adaptable microenvironments tailored to specific substrates,similar to how enzymes work.This strategy has shown great promise in asymmetric catalysis,cascade reactions,and green chemistry applications.Recent advances focus on leveraging less conventional noncovalent forces to expand the toolbox of supramolecular strategies in catalysis.展开更多
The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Coval...The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.展开更多
Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt ...Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt oxyhydroxide @covalent organic frameworks(CoOOH@COFs) S-scheme heterojunction was synthesized,which combined the visible-light-driven photocatalysis and peroxymonosulfate(PMS) activation to synergistically generate abundant reactive oxygen species(ROSs) for TCS degradation.The degradation efficiency of TCS reached 100 % within 8 min in the Vis-CoOOH@COFs/PMS system,and the reaction rate constant was 0.456 min^(-1),which was nearly 1.90 and 2.85 times that of single Co OOH and COFs,and2.36 times that under dark condition,respectively.The density functional theory(DFT) calculations confirmed the energy band bending of CoOOH@COFs and S-scheme charge transport from COFs to Co OOH.Both experimental and theoretical analyses indicated that Co OOH@COFs in photocatalytic-PMS activation systems synergistically facilitated photo-generated carrier separation,enhanced interfacial electron transfer,accelerated PMS activation,and generated multiple ROSs.In particular,photogenerated electrons(e^(-))accelerated the Co(Ⅲ)/Co(Ⅱ) redox cycle,while the PMS captured the e-,which significantly decreased the charge combination of Co OOH@COFs.Radicals(O_(2)^(·-),^(·)OH,and SO_(4)^(·-)) and non-radicals(such as ^(1)O_(2),h^(+),and e^(-)) were both presented in the Vis-CoOOH@COFs/PMS system,with O_(2)^(-) playing a dominant role in TCS degradation.Furthermore,the pathway of TCS degradation and toxicity of intermediates were explored by DFT calculation and transformation product identification.Importantly,the environmentally friendly CoOOH@COFs S-scheme heterojunction exhibited excellent stability and reusability.In conclusion,this study innovatively designed an S-scheme heterojunction in the photocatalytic-PMS activation system,providing guidance and theoretical support for efficient and eco-friendly wastewater treatment.展开更多
Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-t...Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-term wearability;however,the integration of these properties remains a significant challenge.Here,we present a biomass-derived conductive elastomer featuring a rationally engineered dynamic crosslinked network integrated with a tunable microporous architecture.This structural design imparts pronounced micromechanical sensitivity,an ultralow density(~0.25 g cm^(−3)),and superior mechanical compliance for adaptive deformation.Moreover,the unique micro-spring effect derived from the porous architecture ensures exceptional stretchability(>500%elongation at break)and superior resilience,delivering immediate and stable electrical response under both subtle(<1%)and large(>200%)mechanical stimuli.Intrinsic dynamic interactions endow the elastomer with efficient room temperature self-healing and complete recyclability without compromising performance.First-principles simulations clarify the mechanisms behind micropore formation and the resulting functionality.Beyond its facile and mild fabrication process,this work establishes a scalable route toward high-performance,sustainable conductive elastomers tailored for next-generation soft electronics.展开更多
Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through...Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through covalent bonds exhibits excellent structural stability.It has been shown that the stationary phases prepared by combining MOF and COF can make up for the poor stability of MOF@SiO_(2),and the MOF/COF composites have superior chromatographic separation performance.However,the traditional methods for preparing COF/MOF based stationary phases are generally solvent thermal synthesis.In this study,a green and low-cost synthesis method was proposed for the preparation of MOF/COF@SiO_(2) stationary phase.Firstly,COF@SiO_(2) was prepared in a choline chloride/ethylene glycol based deep eutectic solvent(DES).Secondly,another acid-base tunable DES prepared by mixing p-toluenesulfonic acid(PTSA)and 2-methylimidazole in different proportions was introduced as the reaction solvent and reactant for rapid synthesis of MOF/COF@SiO_(2).Compared with the toxic transition metal-based MOFs selected in most previous studies,a lightweight and non-toxic S-zone metal(calcium) based MOF was employed in this study.PTSA and calcium will form the calcium/oxygen-containing organic acid framework in acidic DES,which assembles with terephthalic acid dissolved in basic DES to form MOF.The strong hydrogen bonding effect of DES can facilitate rapid assembly of Ca-MOF.The obtained Ca-MOF/COF@SiO_(2) can be used for multi-mode chromatography to efficiently separate multiple isomeric/hydrophilic/hydrophobic analytes.The synthesis method of Ca-MOF/COF@SiO_(2) is green and mild,especially the use of acid-base tunable DES promotes the rapid synthesis of non-toxic Ca-MOF/COF@silica composites,which offers an innovative approach of greenly synthesizing novel MOF/COF stationary phases and extends their applications in the field of chromatography.展开更多
Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent ...Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent organic framework(COF) scaffold membrane with gate-lane nanostructure for efficient Li^(+)/Mg^(2+) separation. COF nanosheets, serving as the scaffold, are intercalated by polyethyleneimine(PEI) to form the permeating layer. Subsequently, PEI on the surface reacts with 1,4-phenylene diisocyanate to form the polyurea gating layer. The gating layer, bearing tailored smaller pore size,affords high rejection to co-ions(Mg^(2+)) and thus high Li^(+)/Mg^(2+) selectivity. The permeating layer, with asymmetric charge and spatial nanostructure for creating individual lanes of Li^(+) and Cl~-, facilitates Li^(+) transport and thus high Li^(+) permeability. The optimum COF scaffold membrane exhibits the permeance of 11.5 L m^(-2) h^(-1)/bar^(-1) and true selectivity of 231.9 with Li^(+) enrichment of 120.2% at the Mg^(2+)/Li^(+) mass ratio of 50, exceeding the ideal selectivity of 80.5 and outperforming all ever-reported positively charged nanofiltration membranes. Our work may stimulate the further thinking about how to design the hierarchical membrane structure to achieve favorable ion mixing effect and break the membrane permeability-selectivity trade-off in chemical separations.展开更多
Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent...Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.展开更多
Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability...Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.展开更多
The sluggish Li^(+)migration kinetics and unstable electrode/electrolyte interface severely hinder the commercial application of high-performance lithium metal batteries(LMBs).Herein,an artificial protective layer is ...The sluggish Li^(+)migration kinetics and unstable electrode/electrolyte interface severely hinder the commercial application of high-performance lithium metal batteries(LMBs).Herein,an artificial protective layer is constructed using zwitterionic covalent organic framework(Z-COF)simultaneously containing sulfonate and ethidium groups,aiming to facilitate rapid,uniform Li^(+)transport and stabilize anode interface.The sulfonate groups with high lithiophilicity provide abundant hopping sites for fast Li^(+)diffusion.The ethidium cations immobilize TFSI-and solvent molecules by ion-dipole interactions,which accelerate the dissociation of LiTFSI and Li^(+)desolvation.Moreover,the monodispersed zwitterionic units coupling with ordered micropore structures in Z-COF create exclusive Li^(+)migration channels,modulate homogeneous space charge distribution,kinetically facilitating uniform Li^(+)deposition.Experiments and theoretical calculations indicate that C-F and S-N bonds of TFSI-exhibit enhanced cleavage susceptibility driven by electrostatic attraction,realizing a LiF/Li_(3)N-rich electrolyte/electrode interface.The designed Z-COF protection layer enables Li|Li symmetrical cells stable cycling over 6300 h at 2 mA cm^(-2)/2 mAh cm^(-2).The Z-COF@Li|LiFePO_(4)(LFP)full cells deliver high-capacity retention of 85.2%after 1000 cycles at 8 C.The assembled Z-COF@Li|LFP pouch cells demonstrate a lifespan of more than 240 cycles.This work provides fresh insights into the practical application of zwitterionic COF in next-generation LMBs.展开更多
文摘CO_(2)reduction technology can promote the resource utilization of carbon and help alleviate global warming and energy supply pressure.It is an effective way to achieve energy conversion and utilization.Covalent organic frameworks(COFs)are porous crystalline materials formed by connecting organic monomers through covalent bonds.They have the characteristics of functional diversity and rich chemical properties.Their advantages,such as high porosity,a wide range of visible light absorption,and excellent charge separation efficiency,give them good potential in CO_(2)capture,separation,and conversion.Currently,Cu is a key metal in the catalytic CO_(2)reduction reaction(CO_(2)RR)for the preparation of high-value-added chemicals.The preparation of highly stable and large-pore Cu-based COFs using COFs as an ideal sacrificial template for loading Cu can be used to develop high-performance electrocatalysts and photocatalysts.In this review,we discuss the latest advancements in this field,including the development of various Cu-based COFs and their applications as catalysts for CO_(2)RR.Here,we mainly introduce the synthesis strategies,some important characterization information,and the applications of electrocatalytic and photocatalytic CO_(2)conversion using these previously reported Cu-based COFs.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20041006).
文摘The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, [CuCl]20[Cp*FeP5]12[Cu-(CH3CN) + 2Cl?]5 has been studied by a density functional approach. Geometrical optimization of the three basic structural units of the molecule is performed with Amsterdam Density Functional Program. The results are in agreement with the experiment. Localized MO’s obtained by Boys-Foster method give a clear picture of the chemical bonding in this molecule. The reason why CuCl can react with Cp*FeP5 in solvent CH3CN to form the fullerene-like molecule is explained in terms of the soft-hard Lewis acid base theory and a new concept of covalence.
基金Project supported by the National Natural Science Foundation of China.
文摘1 Introduction Generally beryllium is considered as a bivalent element, which implies that its oxidation state is+2. However, almost all compounds of beryllium are covalent ones with partial ionic character, even those formed with the most electronegative elements F and O, e. g. BeF<sub>2</sub> and BeO. The coordination numbers of beryllium in its compounds are 2, 3 and 4. Some people consider the coordination number as covalence, but we think that they are
基金the Natural Science Foundation of ZhejiangProvince(No.LZ24B020005)the National Natural Science Foundation of China(No.22071040)for financial support.
文摘High-sensitive quantitative determination of alpha-fetoprotein(AFP)is of crucial importance for early clinical diagnosis of cancers.Herein,an AuNPs-free electrochemical immunosensor(Ab1-Fc-COF)was prepared from a carboxylic group enriched COF by post-functionalization with detecting antibody(Ab1)and ferrocene(Fc),and used for electrochemical detection of AFP.Due to the small,homogeneous pore size of the COF,Ab1 with a big size was immobilized on the surface of the COF,while Fc with a small size was covalently modified both on the surface and in the pores of COF.The covalently immobilized Ab1 was quite stable and beneficial to specifically detect AFP biomarkers.Meanwhile,the enriched Fc molecules not only improved the conductivity of the COF,but also effectively transferred and amplified the electrochemical signal.This proposed immunosensor exhibited high sensitivity in detecting AFP with a detection limit of 0.39 pg/mL(S/N of 3:1)and a wide linear response range spanning from 1 pg/mL to 100 ng/mL when plotted against logarithmic concentrations.Furthermore,this immunosensor showed excellent selectivity,stability and reproducibility in the testing of real samples.This study presents an innovative prototype for construction of a precious metal-free,antibody-directly-immobilized,simple and stable electrochemical immunoprobe.
基金supported by the Natural Science Foundation(NSF)of China(Nos.22205015,22175020,and 22235001)the National Postdoctoral Program for Innovative Talents(No.BX20220032)+2 种基金the China Postdoctoral Science Foundation Funded Project(No.2022BG013)the Fundamental Research Funds for the Central Universities(Nos.00007709,00007770,and FRFBR-23-02B)University of Science and Technology Beijing is gratefully acknowledged.
文摘In comparison with their 2D and 3D counterparts,1D covalent organic frameworks(COFs)have rarely been investigated due to the synthetic challenge arising from the strict necessary matching in the molecular symmetry between corresponding building blocks and linking units in addition to the unmanageable packing of 1D organic chains once formed.Herein,two novel imide-linked 1D COFs with phthalocyanine building blocks,namely NiPc-CZDM-COF and NiPc-CZDL-COF,were fabricated from the hydrothermal synthesis reaction of 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato nickel(II)(NiPc(COOH)_(8))with 9H-carbazole-3,6-diamine(CZDM)and 4,4′-(9H-carbazole-3,6-diyl)dianiline(CZDL),respectively.Two COFs have high crystallinity on the basis of powder X-ray diffraction analysis and high-resolution transmission electron microscopy.Due to their high ratio of exposed active centers on the edge sites of porous ribbons,both NiPc-CZDM-COF and NiPc-CZDL-COF electrodes display high utilization efficiency of NiPc electroactive sites of 8.0%and 7.5% according to the electrochemical measurement,resulting in their excellent capacity toward electrocatalytic nitrate reduction with the nitrate-to-NH3 Faradaic efficiency of nearly 100%.In particular,NiPc-CZDM-COF electrode exhibits superior electrocatalytic performance with high NH3 partial current density of−246 mA/cm^(2),ammonia yield rate of 19.5 mg cm^(−2) h^(−1),and turnover frequency of 5.8 s^(−1) at−1.2 V in an H-type cell associated with its higher conductivity.This work reveals the good potential of 1D porous crystalline materials in electrocatalysis.
基金supported by the grants from National Key R&D Program of China(No.2022YFA1104800)Shenzhen Science and Technology Program(No.JCYJ20210324124214038)+4 种基金National Natural Science Foundation of China(Nos.52072418,82300016)Natural Science Foundation of Guangdong Province(No.2023A1515140072)Shenzhen Key Laboratory of Neural Cell Reprogramming and Drug Research,Social Development Science and Technology Key Project of Dongguan(No.20231800940512)the National Medical Research Council(NMRC,No.23-0740-A0001)the Ministry of Education(MOE,No.T2EP10222-0002)of Singapore.
文摘Lysine-targeting reversible covalent inhibitors,particularly salicylaldehyde-based compounds such as the Food and Drug Administration(FDA)-approved drug Voxelotor,exhibit significant therapeutic potential but are limited by challenges including instability and off-target effects.To overcome these limitations in kinase inhibitor A5,we devised a pH-responsive prodrug strategy by masking its reactive aldehyde group with an acid-labile hydrazone linkage and enhancing intracellular delivery through conjugation with FK506.The optimized prodrug demonstrated robust antitumor efficacy in K562 tumor-bearing mice.Furthermore,the incorporation of the photosensitizer chlorin e6(Ce6)led to the formation of self-assembled nanoparticles(AKNP),which not only improved physiological stability and prolonged tumor retention but also enabled light-triggered release of A5 in conjunction with photodynamic therapy(PDT).Our study thus presents a promising prodrug self-assembly strategy that combines the on-demand release of a novel lysine-targeting,reversible covalent kinase inhibitor with PDT in clinical cancer therapy.
基金supported by the National Key R&D Program of China(No.2023YFA1507204)National Natural Science Foundation ofChina(Nos.22475074,22171139,22225109,22302055)+4 种基金Natural Science Foundation of Guangdong Province(No.2023B1515020076)Key Scientific Research Project Plan of Colleges and Universities of Henan Province(No.24B150004)The Double Thousand Talents Plan of Jiangxi Province(No.jxsq2023102003)Project supported by the Guangdong Provincial Key Laboratory of Carbon Dioxide Resource Utilization(No.2024B121201001)Project supportedby the Major Research plan of the National Natural Science Foundation of China(No.92461310).
文摘Polyimide-linkage covalent organic frameworks(PI-COFs),as a subclass of the COFs material family,featuring the unique combination of excellent thermal stability of polyimide,tunable pore sizes,as well as high crystallinity and surface area of COFs,are expected to be a novel type of promising crystalline porous material with potential applications in adsorption and separation,catalysis,chemical sensing,and energy storage.Therefore,it is increasingly important to summarize polyimide-linkage in COFs and related applications and provide in-depth insight to accelerate future development.In this review,we offer a comprehensive overview of recent advancements in PI-COFs,emphasizing their synthesis methods,design principles and applications.Finally,our brief outlooks on the current challenges and future developments of PI-COFs are provided.Overall,this review aims to guide the recent and future development of PI-COFs.
基金financially supported by the National Natural Science Foundation of China(No.52303209)the“Lingyan”Program of Zhejiang Province(No.2024C03076)+1 种基金Zhejiang University K.P.Chao’s High Technology Development Foundationthe generous support provided by the joint research fund from the Shaoxing Institute of Zhejiang University and Shaoxing Maternity and Child Health Care Hospital。
文摘Responsive colorimetric materials exhibit significant potential for application in fields such as smart food packaging and wound monitoring.The functional integration of pH-indicators with material carriers enables breakthrough applications in nontraditional domains.In this study,we developed a novel material covalently grafted with a pH indicator that exhibited naked-eye pH-responsive color shifts.The covalent grafting of pH-responsive bromothymol blue onto carboxymethyl cellulose(CMC)was confirmed using advanced characterization techniques,including Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy.The pH-sensitive chromophore was covalently immobilized onto the CMC matrix through esterification,thereby establishing firm chemical conjugation.Moreover,a superior color-changing performance was achieved within several minutes in response to different pH values.The reusability and stability of this material offer distinct advantages over single-use pH test strips.pH-responsive colorimetric materials hold promise for efficient,noninvasive monitoring in intelligent packaging(food freshness),medical diagnostics(wound status,infections),biosensing,and environmental applications.
基金supported by the National Natural Science Foundation of China (Nos.22174067,22204078,and 22374077)the Natural Science Foundation of Jiangsu Province of China (No.BK20220370)+3 种基金Jiangsu Provincial Department of Education (No.22KJB150009)State Key Laboratory of Analytical Chemistry for Life Science (No.SKLACLS2218)the Priority Academic Program Development of Jiangsu Higher Education Institutions,Jiangsu Association for Science and Technology (No.TJ-2023-076)Shanghai Synchrotron Radiation Facility Beamline BL17B1 (No.2021-NFPSPT-006657)。
文摘This research explores the influence of crystallinity on gas chromatographic(GC) separation using covalent organic frameworks(COFs) as stationary phases.Three COF materials(CTF-DCBs) with varying crystallinity were synthesized and characterized.CTF-DCB-1,with superior crystallinity,demonstrated highselectivity GC separation of benzene isomers as well as styrene/phenylacetylene mixtures,while CTFDCB-2 and CTF-DCB-3 exhibited lower crystallinity and worse separation performance.Thermodynamic and kinetic tests showed that CTF-DCB-1 had the worst thermodynamic adsorption but low diffusion mass transfer resistance,which resulted in the best separation.Therefore,optimizing the crystallinity of COFs is necessary for balancing the kinetic diffusion and thermodynamic interactions towards the analytes,achieving high-performance GC stationary phases.
基金the Young Elite Scientists Sponsorship Program by JXAST(2024QT11)the National Natural Science Foundation of China(22465001,22309003)the Jiangxi Provincial Natural Science Foundation(20232BAB203042,20242BAB22002).
文摘As a key low-carbon energy source,nuclear power plays a vital role in the global transition toward sustainable energy.Photocatalytic uranium extraction from seawater(UES)offers a promising solution to ensure long-term uranium supply but is challenged by ultra-low uranium concentrations and ion interference.To overcome these issues,we design three diketopyrrolopyrrole-based covalent organic frameworks(COFs)via a synergisticπ-extended lock and carboxyl-functionalized anchor molecular engineering strategy.Among them,TPy-DPP-COF features a covalently lockedπ-conjugated structure that enhances planarity,optimizes energy alignment,and minimizes exciton binding energy,thereby promoting charge transfer and suppressing recombination.Concurrently,carboxyl groups enable uranyl-specific coordination and create local electric fields to facilitate charge separation.These features contribute to the outstanding performance of TPy-DPP-COF,which achieves a high uranium adsorption capacity of 16.33 mg g−1 in natural seawater under irradiation,with only 29.3%capacity loss after 10 cycles,surpassing industrial benchmarks.Density functional theory(DFT)calculations and experimental studies reveal a synergistic photocatalysis-adsorption pathway,with DPP units acting as active sites for uranium reduction.This work highlights a molecular design strategy for developing efficient COF-based photocatalysts for practical marine uranium recovery.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (No.KJQN202400807)Natural Science Foundation of Shanghai (No.23ZR1419600)。
文摘Interlocked covalent organic cages have aesthetic skeletons endowed with structural and topological complexity.Their self-assembly provides a unique possibility to mimic the hierarchical self-assembly of biomacromolecules.In recent years,significant progresses in interlocked covalent organic cages have been witnessed.Different topological structures have been fabricated via various non-template induced methods,and diverse weak interactions are demonstrated to play critical roles in guiding the formation of interlocked structures.Therefore,this article systematically summarizes the recent advances in interlocked covalent organic cages,especially their design,synthesis,and self-assembly properties.Depending on different types of chemical reactions,irreversible and reversible reactions are separately introduced.In each section,proper monomer selection,critical topology design,key driving forces as well as detailed interlocked mechanisms for the formation of interlocked structures,and their self-assembly behaviors in single crystals are discussed detailedly.Finally,the challenge and future development of interlocked covalent organic cages are briefly prospected.
文摘Supramolecular catalysis uses noncovalent interactions,such as hydrogen bonding,π-π stacking,and host-vip recognition,to control reactivity and selectivity in chemical reactions [1,2].Unlike traditional covalent catalysis,supramolecular systems can create dynamic and adaptable microenvironments tailored to specific substrates,similar to how enzymes work.This strategy has shown great promise in asymmetric catalysis,cascade reactions,and green chemistry applications.Recent advances focus on leveraging less conventional noncovalent forces to expand the toolbox of supramolecular strategies in catalysis.
基金financially supported by the National Natural Science Foundation of China (No.51972302)。
文摘The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.
文摘Triclosan(TCS) poses harmful risks to ecosystems and human health owing to its endocrine-disrupting effects.Therefore,developing an efficient and sustainable technology to degrade TCS is urgently needed.Herein,cobalt oxyhydroxide @covalent organic frameworks(CoOOH@COFs) S-scheme heterojunction was synthesized,which combined the visible-light-driven photocatalysis and peroxymonosulfate(PMS) activation to synergistically generate abundant reactive oxygen species(ROSs) for TCS degradation.The degradation efficiency of TCS reached 100 % within 8 min in the Vis-CoOOH@COFs/PMS system,and the reaction rate constant was 0.456 min^(-1),which was nearly 1.90 and 2.85 times that of single Co OOH and COFs,and2.36 times that under dark condition,respectively.The density functional theory(DFT) calculations confirmed the energy band bending of CoOOH@COFs and S-scheme charge transport from COFs to Co OOH.Both experimental and theoretical analyses indicated that Co OOH@COFs in photocatalytic-PMS activation systems synergistically facilitated photo-generated carrier separation,enhanced interfacial electron transfer,accelerated PMS activation,and generated multiple ROSs.In particular,photogenerated electrons(e^(-))accelerated the Co(Ⅲ)/Co(Ⅱ) redox cycle,while the PMS captured the e-,which significantly decreased the charge combination of Co OOH@COFs.Radicals(O_(2)^(·-),^(·)OH,and SO_(4)^(·-)) and non-radicals(such as ^(1)O_(2),h^(+),and e^(-)) were both presented in the Vis-CoOOH@COFs/PMS system,with O_(2)^(-) playing a dominant role in TCS degradation.Furthermore,the pathway of TCS degradation and toxicity of intermediates were explored by DFT calculation and transformation product identification.Importantly,the environmentally friendly CoOOH@COFs S-scheme heterojunction exhibited excellent stability and reusability.In conclusion,this study innovatively designed an S-scheme heterojunction in the photocatalytic-PMS activation system,providing guidance and theoretical support for efficient and eco-friendly wastewater treatment.
基金supported by National Natural Science Foundation of China(No.52103044)Double First-Class Initiative University of Science and Technology of China(KY2400000037)the Young Talent Programme(GG2400007009).
文摘Conductive elastomers combining micromechanical sensitivity,lightweight adaptability,and environmental sustainability are critically needed for advanced flexible electronics requiring precise responsiveness and long-term wearability;however,the integration of these properties remains a significant challenge.Here,we present a biomass-derived conductive elastomer featuring a rationally engineered dynamic crosslinked network integrated with a tunable microporous architecture.This structural design imparts pronounced micromechanical sensitivity,an ultralow density(~0.25 g cm^(−3)),and superior mechanical compliance for adaptive deformation.Moreover,the unique micro-spring effect derived from the porous architecture ensures exceptional stretchability(>500%elongation at break)and superior resilience,delivering immediate and stable electrical response under both subtle(<1%)and large(>200%)mechanical stimuli.Intrinsic dynamic interactions endow the elastomer with efficient room temperature self-healing and complete recyclability without compromising performance.First-principles simulations clarify the mechanisms behind micropore formation and the resulting functionality.Beyond its facile and mild fabrication process,this work establishes a scalable route toward high-performance,sustainable conductive elastomers tailored for next-generation soft electronics.
基金supported by National Natural Science Foundation of China (Nos.21906124,32302202)Natural Science Foundation of Hubei Province (No.2017CFB220)Natural Science Foundation of Shandong Province (No.ZR2023MH278)。
文摘Metal organic framework(MOF) assembled with coordination bonds has the disadvantage of poor stability that limits its application in the field of stationary phase,while covalent organic framework(COF)assembled through covalent bonds exhibits excellent structural stability.It has been shown that the stationary phases prepared by combining MOF and COF can make up for the poor stability of MOF@SiO_(2),and the MOF/COF composites have superior chromatographic separation performance.However,the traditional methods for preparing COF/MOF based stationary phases are generally solvent thermal synthesis.In this study,a green and low-cost synthesis method was proposed for the preparation of MOF/COF@SiO_(2) stationary phase.Firstly,COF@SiO_(2) was prepared in a choline chloride/ethylene glycol based deep eutectic solvent(DES).Secondly,another acid-base tunable DES prepared by mixing p-toluenesulfonic acid(PTSA)and 2-methylimidazole in different proportions was introduced as the reaction solvent and reactant for rapid synthesis of MOF/COF@SiO_(2).Compared with the toxic transition metal-based MOFs selected in most previous studies,a lightweight and non-toxic S-zone metal(calcium) based MOF was employed in this study.PTSA and calcium will form the calcium/oxygen-containing organic acid framework in acidic DES,which assembles with terephthalic acid dissolved in basic DES to form MOF.The strong hydrogen bonding effect of DES can facilitate rapid assembly of Ca-MOF.The obtained Ca-MOF/COF@SiO_(2) can be used for multi-mode chromatography to efficiently separate multiple isomeric/hydrophilic/hydrophobic analytes.The synthesis method of Ca-MOF/COF@SiO_(2) is green and mild,especially the use of acid-base tunable DES promotes the rapid synthesis of non-toxic Ca-MOF/COF@silica composites,which offers an innovative approach of greenly synthesizing novel MOF/COF stationary phases and extends their applications in the field of chromatography.
基金financial support from the National Natural Science Foundation of China (22338011, 22378299)Hainan Province Science and Technology Special Fund (ZDYF2025SHFZ025)+1 种基金Ningbo Key Research and Development Project (2022Z121)the China Postdoctoral Science Foundation (2025M771194)。
文摘Due to complex ion-ion and ion-membrane interactions, creating innovative membrane structures to acquire favorable ion mixing effect and high separation performance remains a big challenge. Herein, we design covalent organic framework(COF) scaffold membrane with gate-lane nanostructure for efficient Li^(+)/Mg^(2+) separation. COF nanosheets, serving as the scaffold, are intercalated by polyethyleneimine(PEI) to form the permeating layer. Subsequently, PEI on the surface reacts with 1,4-phenylene diisocyanate to form the polyurea gating layer. The gating layer, bearing tailored smaller pore size,affords high rejection to co-ions(Mg^(2+)) and thus high Li^(+)/Mg^(2+) selectivity. The permeating layer, with asymmetric charge and spatial nanostructure for creating individual lanes of Li^(+) and Cl~-, facilitates Li^(+) transport and thus high Li^(+) permeability. The optimum COF scaffold membrane exhibits the permeance of 11.5 L m^(-2) h^(-1)/bar^(-1) and true selectivity of 231.9 with Li^(+) enrichment of 120.2% at the Mg^(2+)/Li^(+) mass ratio of 50, exceeding the ideal selectivity of 80.5 and outperforming all ever-reported positively charged nanofiltration membranes. Our work may stimulate the further thinking about how to design the hierarchical membrane structure to achieve favorable ion mixing effect and break the membrane permeability-selectivity trade-off in chemical separations.
基金financially supported by the Innovation Capability Support Program of Shaanxi—Science and Technology Innovation Team Project(No.2025RS-CXTD-024)the Fundamental Research Foundation of SHCCIG New Materials Technology Research Institute Co.,Ltd(No.D5204230171)+3 种基金the Fundamental Research Funds for the Central Universities(G2025KY05240)the Natural Science Basic Research Program of Shaanxi(Program No.2024JC-YBQN-0073)the Fundamental Research Funds for the Central Universities(No.D5000250204)Young Talent Fund of Association for Science and Technology in Shaanxi(No.20230101)。
文摘Covalent organic frameworks(COFs)are considered promising catalysts for photocatalytic CO_(2)reduction reaction(pCO_(2)RR)due to facilitated regulations.However,the instability of COFs with dynamic reversible covalent bonds and the limited modifiability of COFs with irreversible covalent bonds restricted the enhancement of the pCO_(2)RR performance.Herein,three phthalocyanine-based COFs with ether-linked,CoOP,CoPOP,and CoBOP,were successfully prepared via in situ polycondensation using modifiable bis-phthalonitrile.CoBOP achieved a record of syngas performance in pCO_(2)RR systems with photosensitizers and sacrificial agents(CO 83.7 mmol g^(-1)h^(-1)and H_254.7 mmol g^(-1)h^(-1)),surpassing most COF photocatalysts.Additionally,CoOP,CoPOP,and CoBOP exhibit stabilities in extreme environments owing to their irreversible covalent bonds.Experimental and density functional theory analyses confirm that the optimally matched the lowest unoccupied molecular orbital of the linking unit between the photosensitizer and active unit endowed Co BOP with the highest photoelectron transfer efficiency among the three catalysts,boosting its pCO_(2)RR activity.This work is highly instructive for designing COFs with structure-adjustable and irreversible covalent bonds.
基金supported by the National Natural Science Foundation of China(Nos.52473080,52403167 and 52173079)the Fundamental Research Funds for the Central Universities(Nos.xtr052023001 and xzy012023037)+1 种基金the Postdoctoral Research Project of Shaanxi Province(No.2024BSHSDZZ054)the Shaanxi Laboratory of Advanced Materials(No.2024ZY-JCYJ-04-12).
文摘Shape memory polymers used in 4D printing only had one permanent shape after molding,which limited their applications in requiring multiple reconstructions and multifunctional shapes.Furthermore,the inherent stability of the triazine ring structure within cyanate ester(CE)crosslinked networks after molding posed significant challenges for both recycling,repairing,and degradation of resin.To address these obstacles,dynamic thiocyanate ester(TCE)bonds and photocurable group were incorporated into CE,obtaining the recyclable and 3D printable CE covalent adaptable networks(CANs),denoted as PTCE1.5.This material exhibits a Young's modulus of 810 MPa and a tensile strength of 50.8 MPa.Notably,damaged printed PTCE1.5 objects can be readily repaired through reprinting and interface rejoining by thermal treatment.Leveraging the solid-state plasticity,PTCE1.5 also demonstrated attractive shape memory ability and permanent shape reconfigurability,enabling its reconfigurable 4D printing.The printed PTCE1.5 hinges and a main body were assembled into a deployable and retractable satellite model,validating its potential application as a controllable component in the aerospace field.Moreover,printed PTCE1.5 can be fully degraded into thiol-modified intermediate products.Overall,this material not only enriches the application range of CE resin,but also provides a reliable approach to addressing environmental issue.
基金supported by the National Natural Science Foundation of China(52472093,52176185)the Department of Science and Technology of Hubei Province of China(2022CFA069,2022BAA086).
文摘The sluggish Li^(+)migration kinetics and unstable electrode/electrolyte interface severely hinder the commercial application of high-performance lithium metal batteries(LMBs).Herein,an artificial protective layer is constructed using zwitterionic covalent organic framework(Z-COF)simultaneously containing sulfonate and ethidium groups,aiming to facilitate rapid,uniform Li^(+)transport and stabilize anode interface.The sulfonate groups with high lithiophilicity provide abundant hopping sites for fast Li^(+)diffusion.The ethidium cations immobilize TFSI-and solvent molecules by ion-dipole interactions,which accelerate the dissociation of LiTFSI and Li^(+)desolvation.Moreover,the monodispersed zwitterionic units coupling with ordered micropore structures in Z-COF create exclusive Li^(+)migration channels,modulate homogeneous space charge distribution,kinetically facilitating uniform Li^(+)deposition.Experiments and theoretical calculations indicate that C-F and S-N bonds of TFSI-exhibit enhanced cleavage susceptibility driven by electrostatic attraction,realizing a LiF/Li_(3)N-rich electrolyte/electrode interface.The designed Z-COF protection layer enables Li|Li symmetrical cells stable cycling over 6300 h at 2 mA cm^(-2)/2 mAh cm^(-2).The Z-COF@Li|LiFePO_(4)(LFP)full cells deliver high-capacity retention of 85.2%after 1000 cycles at 8 C.The assembled Z-COF@Li|LFP pouch cells demonstrate a lifespan of more than 240 cycles.This work provides fresh insights into the practical application of zwitterionic COF in next-generation LMBs.
