Two-dimensional(2D)metal/covalent organic framework(MOF/COF)materials have ultra-thin thickness and large surface area.These advantages bestow them the characteristics of low resistance and high flux in the process of...Two-dimensional(2D)metal/covalent organic framework(MOF/COF)materials have ultra-thin thickness and large surface area.These advantages bestow them the characteristics of low resistance and high flux in the process of material transportation.Meanwhile,more active sites promote their application in the fields of catalysis and sensing.Recently,2D MOF/COF materials usher in a new wave of research.It is necessary to summarize the latest developments in this field in a timely and systematic manner and clarify future trends.In this review,we firstly introduce the advantages of 2D MOF/COF materials in hetero-porous structure and functional modification.Then,we discuss advanced strategies for preparing 2D MOF/COF materi-als,such as in-situ growth,interface synthesis,exfoliation method,electrochemical method,surfactant-assisted synthesis,and laminated assembly of MOF/COF nanosheets.Finally,we summarize the applications of 2D MOF/COF materials in membrane separation,sensors,and energy storage.In ad-dition,we discuss some unresolved scientific and technological challenges related to the future prospects of this field.展开更多
Two-dimensional(2D)olefin-linked covalent organic frameworks(COFs)with excellentπ-electron communication and high stability are emerging as promising crystalline polymeric materials.However,because of the limited spe...Two-dimensional(2D)olefin-linked covalent organic frameworks(COFs)with excellentπ-electron communication and high stability are emerging as promising crystalline polymeric materials.However,because of the limited species of COFs,their characteristics,processability and potential applications have not been completely understood and explored.In this work,we prepared two novel olefin-linked 2D COFs through Knoevenagel condensation of 2,4,6-trimethyl-1,3,5-triazine with tritopic triazine-cored aldehydes.The resulting COFs exhibit highly crystalline honeycomb-like structures stacked from hexagonallatticed polymeric layers and display well-defined nanofibrillar morphologies with the uniform diameters of ca.80 nm and ultra-lengths up to several micrometers.Such COF nanofibers can be readily composited with carbon nanotubes into high-quality continuous thin films,which are further compacted by a typical hot-pressing process to enhance their densities and mechanical strength without changing their fibrous microstructures.Such film-fabricated interdigital microelectrodes and the ionogel electrolyte are assembled into planar micro-supercapacitors(MSCs),which exhibit an outstanding areal capacitance of 44.3 mF cm^-2,large operating voltage window of 2.5 V,high volumetric energy density of 38.5 mWh cm^-3 as well as excellent cycling stability.展开更多
Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material ...Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.展开更多
Covalent organic frameworks（COFs） represent an emerging class of porous crystalline materials and have recently shown interesting applications from catalysis to optoelectronic devices.In this review,by covering most...Covalent organic frameworks（COFs） represent an emerging class of porous crystalline materials and have recently shown interesting applications from catalysis to optoelectronic devices.In this review,by covering most of the reported work,we summarized the research progress of two-dimensional（2D）porphyrin- and phthalocyanine-based COFs,with highlighting the synthesis of these 2D COFs via various dynamic covalent reactions and emphasizing their potential applications in different areas.展开更多
基金This work was supported by the National Key R&D Program of China(2018YFA0703200)the National Natural Science Foundation of China(51773041,61890940)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB30000000)the Chongqing Bayu Scholar Program(DP2020036)and Fudan University.
文摘Two-dimensional(2D)metal/covalent organic framework(MOF/COF)materials have ultra-thin thickness and large surface area.These advantages bestow them the characteristics of low resistance and high flux in the process of material transportation.Meanwhile,more active sites promote their application in the fields of catalysis and sensing.Recently,2D MOF/COF materials usher in a new wave of research.It is necessary to summarize the latest developments in this field in a timely and systematic manner and clarify future trends.In this review,we firstly introduce the advantages of 2D MOF/COF materials in hetero-porous structure and functional modification.Then,we discuss advanced strategies for preparing 2D MOF/COF materi-als,such as in-situ growth,interface synthesis,exfoliation method,electrochemical method,surfactant-assisted synthesis,and laminated assembly of MOF/COF nanosheets.Finally,we summarize the applications of 2D MOF/COF materials in membrane separation,sensors,and energy storage.In ad-dition,we discuss some unresolved scientific and technological challenges related to the future prospects of this field.
基金the National Natural Science Foundation of China(21774072,and 21720102002)financially supported by the Open Project Programs of the State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(2019-01,Jilin University)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials(KF2019,Donghua University)。
文摘Two-dimensional(2D)olefin-linked covalent organic frameworks(COFs)with excellentπ-electron communication and high stability are emerging as promising crystalline polymeric materials.However,because of the limited species of COFs,their characteristics,processability and potential applications have not been completely understood and explored.In this work,we prepared two novel olefin-linked 2D COFs through Knoevenagel condensation of 2,4,6-trimethyl-1,3,5-triazine with tritopic triazine-cored aldehydes.The resulting COFs exhibit highly crystalline honeycomb-like structures stacked from hexagonallatticed polymeric layers and display well-defined nanofibrillar morphologies with the uniform diameters of ca.80 nm and ultra-lengths up to several micrometers.Such COF nanofibers can be readily composited with carbon nanotubes into high-quality continuous thin films,which are further compacted by a typical hot-pressing process to enhance their densities and mechanical strength without changing their fibrous microstructures.Such film-fabricated interdigital microelectrodes and the ionogel electrolyte are assembled into planar micro-supercapacitors(MSCs),which exhibit an outstanding areal capacitance of 44.3 mF cm^-2,large operating voltage window of 2.5 V,high volumetric energy density of 38.5 mWh cm^-3 as well as excellent cycling stability.
基金financial aid from the National Natural Science Foundation of Guangdong Province (Grant No. 2016A030310435)Youth Scholars Fundation of South China Normal University (Grant No. 15KJ01)
文摘Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.
基金supported by National Natural Science Foundation of China(No.21572170)the Research Fund for the Doctoral Program of Higher Education of China(No.20130141110008)+2 种基金the Outstanding Youth Foundation of Hubei Province(No.2015CFA045)the Beijing National Laboratory for Molecular Sciencesthe Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices(No.KFJJ201505)
文摘Covalent organic frameworks（COFs） represent an emerging class of porous crystalline materials and have recently shown interesting applications from catalysis to optoelectronic devices.In this review,by covering most of the reported work,we summarized the research progress of two-dimensional（2D）porphyrin- and phthalocyanine-based COFs,with highlighting the synthesis of these 2D COFs via various dynamic covalent reactions and emphasizing their potential applications in different areas.
