The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precis...The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precisely regulate the growth and stacking of COF grains through a moderate reversed Schiff base reaction,realizing the direct synthesis of COF nanofibers(CNFs)with high aspect ratio(L/D=103.05)and long length(>20μm).An individual CNF exhibits a biomimetic scale-like architecture,achieving superior flexibility and fatigue resistance under dynamic bending via a multiscale stress dissipation mechanism.Taking advantages of these structural features,we engineer CNF aerogels(CNF-As)with programmable porous structures(e.g.,honeycomb,lamellar,isotropic)via directional ice-template methodology.CNF-As demonstrate 100%COF content,high specific surface area(396.15 m^(2)g^(-1))and superelasticity(~0%elastic deformation after 500 compression cycles at 50%strain),outperforming most COF-based counterparts.Compared with the conventional COF aerogels,the unique structural features of CNF-A enable it to perform outstandingly in uranium extraction,with an 11.72-fold increment in adsorption capacity(920.12 mg g^(-1))and adsorption rate(89.9%),and a 2.48-fold improvement in selectivity(U/V=2.31).This study provides a direct strategy for the development of next-generation COF materials with outstanding functionality and structural robustness.展开更多
Covalent organic frameworks(COFs)are an emerging class of porous crystalline materials formed by the precise assembly of organic molecular building blocks into extended periodic structures via strong covalent bonds.Th...Covalent organic frameworks(COFs)are an emerging class of porous crystalline materials formed by the precise assembly of organic molecular building blocks into extended periodic structures via strong covalent bonds.They feature well-defined pore structure,high specific surface area,and tunable physicochemical properties,endowing them with broad application prospects in gas storage,molecular separation.展开更多
2025年1月9日,天津大学姜忠义教授团队在Angewandte Chemie International Edition期刊发表题为“Confining Phosphoric Acid in Quaternized COF Channels for Ultra-stable and Fast Anhydrous Proton Transport”的研究论文,团队成...2025年1月9日,天津大学姜忠义教授团队在Angewandte Chemie International Edition期刊发表题为“Confining Phosphoric Acid in Quaternized COF Channels for Ultra-stable and Fast Anhydrous Proton Transport”的研究论文,团队成员逢霄为论文第一作者,姜忠义教授为论文通讯作者.展开更多
Ionic covalent organic framework(COF)lamellar membranes are the alternative materials as promising Li^(+)conductors for all-solid-state lithium batteries.However,COF lamellar membrane suffers from poor structural stab...Ionic covalent organic framework(COF)lamellar membranes are the alternative materials as promising Li^(+)conductors for all-solid-state lithium batteries.However,COF lamellar membrane suffers from poor structural stability and inevitable cross-layer transfer resistance due to the weak interaction at interface of adjacent nanosheets.Herein,a lamellar polymer-threaded ionic COF(PEI@TpPa-SO_(3)Li)composite electrolyte with single Li^(+)conduction was prepared by assembling lithium sulfonated COF(TpPa-SO_(3)Li)nanosheets and then threading them with polyethyleneimine(PEI)chains.It reveals that the threaded PEI chains induce the oriented permutation of pore channel of PEI@TpPa-SO_(3)Li electrolyte through electrostatic interaction between-NH_(2)/-NH-and-SO_(3)Li groups.This enables the construction of continuous and aligned-SO_(3)^(-)...Li^(+)...-NH_(2)/-NH-pairs along pore channels,which act as efficient Li^(+)conducting sites and afford high Li^(+)hopping conduction(1.4×10^(-4)S cm^(-1)at 30℃)with a high Young's modulus of 408.7 MP and wide electrochemical stability window of 0~4.7 V.The assembled LiFePO_(4)‖Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)‖Li half-cells achieve high discharge capacities of 155.0 mAh g^(-1)and 167.2 mAh g^(-1)at 30℃under0.2 C,respectively,with high capacity retention of 98%after 300 cycles.This study provides an alternative route to highly ion-conductive lamellar porous electrolytes for high-performance energy devices.展开更多
With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block elec...With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block electromagnetic radiation for ensuring normal operation of electronic equipment and human health,while providing heat insulation to improve energy efficiency and protect equipment from high temperatures.In this study,we employ covalent organic skeleton(COF)to optimize Ti_(3)C_(2)T_(x)MXene layers and successfully prepare MXene@COF heterostructures.This structure maintained the unique two-dimensional architecture of Ti_(3)C_(2)T_(x)MXene while preventing aggregation and self-stacking of MXene nanosheets through the outer COF layer.The modification increases material porosity and significantly enhances electrical conductivity.We incorporated the heterostructure into acrylamidegelatin hydrogels and controlled shielding efficiency by varying COF content.Results demonstrate that the MXene@COF-based hydrogel(15 mm p-pheny lenedi amine)exhibits high toughness,strong electromagnetic shielding capability,infrared stealth performance,and thermal insulation properties.In the X-band,mechanical tests show only 3 mm in thickness and 0.90 wt%MXene@COF content,electromagnetic shielding efficiency(EMI SE)of the material is as high as 37.52 dB,and the average total electromagnetic shielding(SE_(T))is 32.01 dB,the compressive stress is 20.85 MPa,the water content is 79.04%,and the electrical conductivity is 1.22 S m^(-1).These finding soffer new possibilities for developing COF-based electromagnetic shielding materials.展开更多
Hydrogen peroxide(H_(2)O_(2))is a crucial oxidant with diverse industrial applications,yet its conventional synthesis suffers from high energy consumption and hazardous byproducts.Photocatalysis offers a sustainable a...Hydrogen peroxide(H_(2)O_(2))is a crucial oxidant with diverse industrial applications,yet its conventional synthesis suffers from high energy consumption and hazardous byproducts.Photocatalysis offers a sustainable alternative,but its efficiency is often compromised by rapid charge recombination.Herein,we reported the rational design of a TiO_(2)/TD-COF S-scheme heterojunction,which achieved a remarkable H_(2)O_(2) production rate of 2162.3µmol g^(−1) h^(−1),representing almost 14-fold enhancement compared to pristine TiO_(2).Through in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)and femtosecond transient absorption spectroscopy(fs-TAS),we demonstrate an ultrafast charge transfer driven by internal electric field(IEF)that efficiently separates photogenerated carriers while preserving their redox potentials.Furthermore,in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and electron paramagnetic resonance(EPR)spectroscopy provide direct experimental evidence for the dual-pathway mechanism,involving both the oxygen reduction reaction(ORR)and water oxidation reaction(WOR).This work demonstrates the potential of S-scheme heterojunction in overcoming the limitations of traditional photocatalytic systems,offering a scalable and sustainable approach for solar-driven H_(2)O_(2) production.展开更多
The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analys...The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analysis indicate that introducing pyrazine units enhances charge migration,leading to increased accumulation of photoinduced electrons on these units,thereby facilitating the two-site,two-electron ORR.Inspired by these theoretical insights,this work designed and fabricated a triazine-pyrazine-based covalent organic framework materials(TTDN-COFs)for H_(2)O_(2) photosynthesis via a polarity-functionalization strategy.The TTDN-COFs demonstrate a significant improvement in the photocatalytic H_(2)O_(2) production rate,reaching 2757.6μmol h^(-1) g^(-1) in pure water–3.2 times higher than that of the triazine-based COFs(TTPH-COFs).Experimental results and theoretical calculations confirm that the incorporation of pyrazine units not only enhances polarization,promoting the separation and migration of charge carriers,but also facilitates the formation of endoperoxide at both the triazine and pyrazine units.The dual adsorption activation sites lower the activation energy barrier for O_(2),thereby accelerating the overall reaction kinetics.These findings highlight the potential of functional-group-mediated polarization engineering as a promising strategy for developing COFs-based H_(2)O_(2) photosynthesis with dual activation sites.展开更多
Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal ...Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal method and filled in polyether block polyamide(PEBAX)to form mixed matrix membranes(MMMs).Various characterization methods such as Fourier transform infrared spectroscopy(FT-IR),Xray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and X-ray diffractometry(XRD)were used to characterize the structure of Dha Tab-COF as well as the MMMs.The effects of operating pressure,operating temperature and the content of Dha Tab-COF particles on the CO_(2)/CH_(4)separation performance of the membranes were investigated.The best separation performance with a CO_(2)permeability of 295.8 barrer(1 barrer=7.52×10^(-18)m^(3)·(STP)·m^(-2)·m·s^(-1)·Pa^(-1))and a CO_(2)/CH_(4)selectivity of 21.6 was achieved when the Dha Tab-COF content is 2%(mass),which were 45.7%and 108.1%higher than that of the pure PEBAX membrane,respectively.展开更多
基金supported by the National Natural Science Foundation of China(No.52403035)the Shanghai Sailing Program(23YF1400300)+1 种基金the Fundamental Research Funds for the Central Universities(2232023D-05)the Weiqiao Teaching and Research Innovation Program.
文摘The lack of macro-continuity and mechanical strength of covalent organic frameworks(COFs)has significantly limited their practical applications.Here,we propose an“alcohol-triggered defect cleavage”strategy to precisely regulate the growth and stacking of COF grains through a moderate reversed Schiff base reaction,realizing the direct synthesis of COF nanofibers(CNFs)with high aspect ratio(L/D=103.05)and long length(>20μm).An individual CNF exhibits a biomimetic scale-like architecture,achieving superior flexibility and fatigue resistance under dynamic bending via a multiscale stress dissipation mechanism.Taking advantages of these structural features,we engineer CNF aerogels(CNF-As)with programmable porous structures(e.g.,honeycomb,lamellar,isotropic)via directional ice-template methodology.CNF-As demonstrate 100%COF content,high specific surface area(396.15 m^(2)g^(-1))and superelasticity(~0%elastic deformation after 500 compression cycles at 50%strain),outperforming most COF-based counterparts.Compared with the conventional COF aerogels,the unique structural features of CNF-A enable it to perform outstandingly in uranium extraction,with an 11.72-fold increment in adsorption capacity(920.12 mg g^(-1))and adsorption rate(89.9%),and a 2.48-fold improvement in selectivity(U/V=2.31).This study provides a direct strategy for the development of next-generation COF materials with outstanding functionality and structural robustness.
文摘Covalent organic frameworks(COFs)are an emerging class of porous crystalline materials formed by the precise assembly of organic molecular building blocks into extended periodic structures via strong covalent bonds.They feature well-defined pore structure,high specific surface area,and tunable physicochemical properties,endowing them with broad application prospects in gas storage,molecular separation.
文摘2025年1月9日,天津大学姜忠义教授团队在Angewandte Chemie International Edition期刊发表题为“Confining Phosphoric Acid in Quaternized COF Channels for Ultra-stable and Fast Anhydrous Proton Transport”的研究论文,团队成员逢霄为论文第一作者,姜忠义教授为论文通讯作者.
基金supported by the financial support from the National Key Research and Development Program(2022YFB3805204,2022YFB3805201)National Natural Science Foundation of China(22478362)+2 种基金Joint Foundation for Science and Technology Research&Development Plan of Henan Province(222301420003 and 232301420038)Key Scientific and Technological Project of Henan Province(242102321032)Foundation of Henan Educational Committee(22A530003)。
文摘Ionic covalent organic framework(COF)lamellar membranes are the alternative materials as promising Li^(+)conductors for all-solid-state lithium batteries.However,COF lamellar membrane suffers from poor structural stability and inevitable cross-layer transfer resistance due to the weak interaction at interface of adjacent nanosheets.Herein,a lamellar polymer-threaded ionic COF(PEI@TpPa-SO_(3)Li)composite electrolyte with single Li^(+)conduction was prepared by assembling lithium sulfonated COF(TpPa-SO_(3)Li)nanosheets and then threading them with polyethyleneimine(PEI)chains.It reveals that the threaded PEI chains induce the oriented permutation of pore channel of PEI@TpPa-SO_(3)Li electrolyte through electrostatic interaction between-NH_(2)/-NH-and-SO_(3)Li groups.This enables the construction of continuous and aligned-SO_(3)^(-)...Li^(+)...-NH_(2)/-NH-pairs along pore channels,which act as efficient Li^(+)conducting sites and afford high Li^(+)hopping conduction(1.4×10^(-4)S cm^(-1)at 30℃)with a high Young's modulus of 408.7 MP and wide electrochemical stability window of 0~4.7 V.The assembled LiFePO_(4)‖Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)‖Li half-cells achieve high discharge capacities of 155.0 mAh g^(-1)and 167.2 mAh g^(-1)at 30℃under0.2 C,respectively,with high capacity retention of 98%after 300 cycles.This study provides an alternative route to highly ion-conductive lamellar porous electrolytes for high-performance energy devices.
基金financially supported by the National Natural Science Foundation of China(No.52163001)Guizhou Provincial Science and Technology Program Project(Nos.Qiankehe Platform Talents-CXTD[2021]005,Qiankehe Platform Talents-GCC[2022]010-1,Qiankehe Platform TalentsGCC[2023]035,Qiankehe Platform Talents-CXTD[2023]003 and Qiankehe Platform Talents-KXJZ[2024]022)+3 种基金Guizhou Minzu University Research Platform(No.GZMUGCZX[2021]01)the Central Guided Local Science and Technology Development Funds Project(No.Qiankehe Zhong Yindi[2023]035)the Doctor Startup Fund of Guizhou Minzu University(No.GZMUZK[2024]QD77)Guizhou Province Special Fund for innovative capacity building of scientific research institutions(Nos.Qiankehe Fuqi[2023]001 and Qiankehe Fuqi[2024]002-1)
文摘With the widespread popularity of electronic equipment and rapid development of wireless communication technology,electromagnetic shielding materials possessing thermal insulation properties can effectively block electromagnetic radiation for ensuring normal operation of electronic equipment and human health,while providing heat insulation to improve energy efficiency and protect equipment from high temperatures.In this study,we employ covalent organic skeleton(COF)to optimize Ti_(3)C_(2)T_(x)MXene layers and successfully prepare MXene@COF heterostructures.This structure maintained the unique two-dimensional architecture of Ti_(3)C_(2)T_(x)MXene while preventing aggregation and self-stacking of MXene nanosheets through the outer COF layer.The modification increases material porosity and significantly enhances electrical conductivity.We incorporated the heterostructure into acrylamidegelatin hydrogels and controlled shielding efficiency by varying COF content.Results demonstrate that the MXene@COF-based hydrogel(15 mm p-pheny lenedi amine)exhibits high toughness,strong electromagnetic shielding capability,infrared stealth performance,and thermal insulation properties.In the X-band,mechanical tests show only 3 mm in thickness and 0.90 wt%MXene@COF content,electromagnetic shielding efficiency(EMI SE)of the material is as high as 37.52 dB,and the average total electromagnetic shielding(SE_(T))is 32.01 dB,the compressive stress is 20.85 MPa,the water content is 79.04%,and the electrical conductivity is 1.22 S m^(-1).These finding soffer new possibilities for developing COF-based electromagnetic shielding materials.
基金supported by the National Natural Science Foundation of China(nos.42207386,U23A20102,22261142666,U24A2071,and 22469001)the Natural Science Foundation of Hubei Province of China(no.2022CFA001).
文摘Hydrogen peroxide(H_(2)O_(2))is a crucial oxidant with diverse industrial applications,yet its conventional synthesis suffers from high energy consumption and hazardous byproducts.Photocatalysis offers a sustainable alternative,but its efficiency is often compromised by rapid charge recombination.Herein,we reported the rational design of a TiO_(2)/TD-COF S-scheme heterojunction,which achieved a remarkable H_(2)O_(2) production rate of 2162.3µmol g^(−1) h^(−1),representing almost 14-fold enhancement compared to pristine TiO_(2).Through in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)and femtosecond transient absorption spectroscopy(fs-TAS),we demonstrate an ultrafast charge transfer driven by internal electric field(IEF)that efficiently separates photogenerated carriers while preserving their redox potentials.Furthermore,in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and electron paramagnetic resonance(EPR)spectroscopy provide direct experimental evidence for the dual-pathway mechanism,involving both the oxygen reduction reaction(ORR)and water oxidation reaction(WOR).This work demonstrates the potential of S-scheme heterojunction in overcoming the limitations of traditional photocatalytic systems,offering a scalable and sustainable approach for solar-driven H_(2)O_(2) production.
文摘The two-electron oxygen reduction reaction(ORR)for H_(2)O_(2) photosynthesis is often hindered by sluggish charge kinetics and a limited number of activation sites.Theoretical predictions based on dipole moment analysis indicate that introducing pyrazine units enhances charge migration,leading to increased accumulation of photoinduced electrons on these units,thereby facilitating the two-site,two-electron ORR.Inspired by these theoretical insights,this work designed and fabricated a triazine-pyrazine-based covalent organic framework materials(TTDN-COFs)for H_(2)O_(2) photosynthesis via a polarity-functionalization strategy.The TTDN-COFs demonstrate a significant improvement in the photocatalytic H_(2)O_(2) production rate,reaching 2757.6μmol h^(-1) g^(-1) in pure water–3.2 times higher than that of the triazine-based COFs(TTPH-COFs).Experimental results and theoretical calculations confirm that the incorporation of pyrazine units not only enhances polarization,promoting the separation and migration of charge carriers,but also facilitates the formation of endoperoxide at both the triazine and pyrazine units.The dual adsorption activation sites lower the activation energy barrier for O_(2),thereby accelerating the overall reaction kinetics.These findings highlight the potential of functional-group-mediated polarization engineering as a promising strategy for developing COFs-based H_(2)O_(2) photosynthesis with dual activation sites.
基金supported by the National Natural Science Foundation of China(No.22271022,No 22378327).
文摘Covalent organic skeletons(COFs)have been widely used in gas separation due to their excellent pore structure,high crystallinity,and high specific surface area.In this work,Dha Tab-COF was synthesized by solvothermal method and filled in polyether block polyamide(PEBAX)to form mixed matrix membranes(MMMs).Various characterization methods such as Fourier transform infrared spectroscopy(FT-IR),Xray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and X-ray diffractometry(XRD)were used to characterize the structure of Dha Tab-COF as well as the MMMs.The effects of operating pressure,operating temperature and the content of Dha Tab-COF particles on the CO_(2)/CH_(4)separation performance of the membranes were investigated.The best separation performance with a CO_(2)permeability of 295.8 barrer(1 barrer=7.52×10^(-18)m^(3)·(STP)·m^(-2)·m·s^(-1)·Pa^(-1))and a CO_(2)/CH_(4)selectivity of 21.6 was achieved when the Dha Tab-COF content is 2%(mass),which were 45.7%and 108.1%higher than that of the pure PEBAX membrane,respectively.
