Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of n...Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of non-covalently bound parallel Te chains, among which covalent-like feature appears.This feature is, we believe, another demonstration of the previously found covalent-like quasi-bonding(CLQB) where wavefunction hybridization does occur. The strength of this inter-chain CLQB is comparable with that of intra-chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV(bulk) to indirect 1.17 eV(2L) and four(two) complex, highly anisotropic and layer-dependent hole(electron) pockets in the first Brillouin zone.It also exhibits an extraordinarily high hole mobility(~10~5 cm^2/Vs) and strong optical absorption along the non-covalently bound direction, nearly isotropic and layer-dependent optical properties, large ideal strength over 20%, better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few-layer Te is an extraordinary-high-mobility, high optical absorption, intrinsic-anisotropy, low-cost-fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This ‘‘one-dimen sion-like" few-layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.展开更多
Nanoparticle photosensitizers possess technical advantages for photocatalytic reactions due to enhanced light harvesting and efficient charge transport.Here we report synthesis of semiconductor nanoparticles through c...Nanoparticle photosensitizers possess technical advantages for photocatalytic reactions due to enhanced light harvesting and efficient charge transport.Here we report synthesis of semiconductor nanoparticles through covalent coupling and assembly of metalloporphyrin with condensed carbon nitride.The resultant nanoparticles consist of light harvesting component from the condensed carbon nitride and photocatalytic sites from the metalloporphyrins.This synergetic particle system effectively initiates efficient charge separation and transport and exhibits excellent photocatalytic activity for CO2 reduction.The CO production rate can reach up to 57μmol/(g·h)with a selectivity of 79%over competing H2 evolution.Controlled experiments demonstrate that the combination of light harvesting with photocatalytic activity via covalent assembly is crucial for the high photocatalytic activity.Due to effective charge separation and transfer,the resultant nanoparticle photocatalysts show exceptional photo stability against photo-corrosion under light irradiation,enabling for long-term utilization.This research opens a new way for the development of stable,effective nanoparticle photocatalysts using naturally abundant porphyrin pigments.展开更多
In order to broaden the absorption range of graphitic carbon nitride,one of the common methods is to couple the well-known photosensitizer porphyrin with graphitic carbon nitride through van der Waals weak in teractio...In order to broaden the absorption range of graphitic carbon nitride,one of the common methods is to couple the well-known photosensitizer porphyrin with graphitic carbon nitride through van der Waals weak in teractions.To date,to combine porphyrin with graphitic carbon nitridethrough covalent in teractions has not been settled.In this work,through rational molecular design,we successfully in corporated porphyrininto the matrixes of graphitic carbon nitride by covale nt bonding via on expot thermal copolymerization.The resulta nt material not only can wide nthe absorption range but also possess the enlarged specific surface area and construction intramolecular heterojunctions which can contributeto improve electron-holes separation efficiency.The resultant photocatalyst exhibited enhanced H2 production rate(7.6 mmol·g^-1·h^-1)and withthe apparent quantum efficiency(AQE)of 13.3%at 450 nm.At the same time,this method opens a way to fabricate graphitic carb on nitridenano sheets via bottom-up strategy.展开更多
Paramagnetic polymer microspheres were synthesized by the inverse suspension polymerizationmethod through polymerization of glycidyl methacrylate,ally glycidyl ether and methacrylamide onthe surface of silica‐coated ...Paramagnetic polymer microspheres were synthesized by the inverse suspension polymerizationmethod through polymerization of glycidyl methacrylate,ally glycidyl ether and methacrylamide onthe surface of silica‐coated Fe3O4nanoparticles using N,N’‐methylene‐bis(acrylamide)as across‐linking agent.Penicillin G acylase(PGA)was covalently immobilized on the surface of theparamagnetic microspheres by reacting the amino groups of the PGA molecules with the epoxygroups of the paramagnetic polymer microspheres.The effect of the SiO2coating and the amount ofparamagnetic Fe3O4nanoparticles on the initial activity and the operational stability of the immobilizedPGA was investigated.The results indicated that SiO2played an important role in the polymerization process and paramagnetic polymer microspheres with a SiO2‐coated Fe3O4nanoparticles mass content of7.5%are an optimal support material for PGA immobilization.Immobilized PGA on the paramagnetic polymer microspheres shows a high initial activity of430U/g(wet)and retains99%of its initial activity after recycling10times.Furthermore,immobilized PGA exhibits high thermal stability,pH stability and excellent reusability,which can be rapidly recycled by the aid of magnet.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.展开更多
In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylam...In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis process.The hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully constructed.The PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response stability.Furthermore,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.展开更多
Due to the various pH liquid environment in nature,the pH-responsive lubricating hydrogel is widely investigated and developed for tissue interface substitute.However,the applied liquid environment will lead to poor m...Due to the various pH liquid environment in nature,the pH-responsive lubricating hydrogel is widely investigated and developed for tissue interface substitute.However,the applied liquid environment will lead to poor mechanical property and weaken the pH-responsive capability.In this work,a carbon dotsenhanced pH-responsive lubricating hydrogel is developed by combining a pH-responsive section of dynamic PVA-borax network into a PAAm covalent polymer network.The formed hydrogel presents a partial gel-sol transition under controlled pH environments.At low pH environments(<6.0),the formed lubricating layer originated from dynamic disassembly of PVA-borax hydrogel,and brings the lubricating properties on the hydrogel surface.Moreover,the mechanical strength and lubrication properties are well promoted by introducing the carbon dots into the hydrogel,the blue sol layer can be observed more visually under the fluorescence microscope.The pH-response also exhibits well reversibility.The prepared hydrogel broadens the idea for designing pH-responsive soft materials for soft lubricating actuator or robot.展开更多
Charge-transporting layers(CTLs)are important in determining the performance and stability of perovskite solar cells(PSCs).Recently,there has been considerable use of self-assembled monolayers(SAMs)as charge-selective...Charge-transporting layers(CTLs)are important in determining the performance and stability of perovskite solar cells(PSCs).Recently,there has been considerable use of self-assembled monolayers(SAMs)as charge-selective contacts,especially for hole-selective SAMs in inverted PSCs as well as perovskite involving tandem solar cells.The SAM-based charge-selective contact shows many advantages over traditional thin-film organic/inorganic CTLs,including reduced cost,low optical and electric loss,conformal coating on a rough substrate,simple deposition on a large-area substrate and easy modulation of energy levels,molecular dipoles and surface properties.The incorporation of various hole-selective SAMs has resulted in high-efficiency single junction and tandem solar cells.This topical review summarizes both the advantages and challenges of SAM-based charge-selective contacts,and discusses the potential direction for future studies.展开更多
Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unsta...Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.展开更多
Astragali Radix(AR)is a clinically used herbal medicine with multiple immunomodulatory activities that can strengthen the activity and cytotoxicity of natural killer(NK)cells.However,owing to the complexity of its com...Astragali Radix(AR)is a clinically used herbal medicine with multiple immunomodulatory activities that can strengthen the activity and cytotoxicity of natural killer(NK)cells.However,owing to the complexity of its composition,the specific active ingredients in AR that act on NK cells are not clear yet.Cell membrane chromatography(CMC)is mainly used to screen the active ingredients in a complex system of herbal medicines.In this study,a new comprehensive two-dimensional(2D)NK-92MI CMC/C18 column/time-of-flight mass spectrometry(TOFMS)system was established to screen for potential NK cell activators.To obtain a higher column efficiency,3-mercaptopropyltrimethoxysilane-modified silica was synthesized to prepare the NK-92MI CMC column.In total,nine components in AR were screened from this system,which could be washed out from the NK-92MI/CMC column after 10 min,and they showed good affinity for NK-92MI/CMC column.Two representative active compounds of AR,isoastragaloside Ⅰ and astragaloside IV,promoted the killing effect of NK cells on K562 cells in a dose-dependent manner.It can thus suggest that isoastragaloside Ⅰ and astragaloside Ⅳ are the main immunomodulatory components of AR.This comprehensive 2D NK-92MI CMC analytical system is a practical method for screening immune cell activators from other herbal medicines with immunomodulatory effects.展开更多
基金supported by the National Natural Science Foundation of China(11274380,91433103,11622437,61674171,and 61761166009)the Fundamental Research Funds for the Central Universities of China and the Research Funds of Renmin University of China(16XNLQ01)+1 种基金The Hong Kong Polytechnic University(G-SB53)J.Q. and C.W. were supported by the Outstanding Innovative Talents Cultivation Funded Programs 2016 and 2017 of Renmin University of China,respectively
文摘Few-layer Tellurium, an elementary semiconductor, succeeds most of striking physical properties that black phosphorus(BP) offers and could be feasibly synthesized by simple solution-based methods. It is comprised of non-covalently bound parallel Te chains, among which covalent-like feature appears.This feature is, we believe, another demonstration of the previously found covalent-like quasi-bonding(CLQB) where wavefunction hybridization does occur. The strength of this inter-chain CLQB is comparable with that of intra-chain covalent bonding, leading to closed stability of several Te allotropes. It also introduces a tunable bandgap varying from nearly direct 0.31 eV(bulk) to indirect 1.17 eV(2L) and four(two) complex, highly anisotropic and layer-dependent hole(electron) pockets in the first Brillouin zone.It also exhibits an extraordinarily high hole mobility(~10~5 cm^2/Vs) and strong optical absorption along the non-covalently bound direction, nearly isotropic and layer-dependent optical properties, large ideal strength over 20%, better environmental stability than BP and unusual crossover of force constants for interlayer shear and breathing modes. All these results manifest that the few-layer Te is an extraordinary-high-mobility, high optical absorption, intrinsic-anisotropy, low-cost-fabrication, tunable bandgap, better environmental stability and nearly direct bandgap semiconductor. This ‘‘one-dimen sion-like" few-layer Te, together with other geometrically similar layered materials, may promote the emergence of a new family of layered materials.
基金E B.acknowledges the support from the National Natural Science Foundation of China(Nos.21771055 and U1604139)Zhongyuan high level talents special support plan(No.204200510010)Scientific and Technological Innovation Team in University of Henan Province(No.20IRTSTHN001).
文摘Nanoparticle photosensitizers possess technical advantages for photocatalytic reactions due to enhanced light harvesting and efficient charge transport.Here we report synthesis of semiconductor nanoparticles through covalent coupling and assembly of metalloporphyrin with condensed carbon nitride.The resultant nanoparticles consist of light harvesting component from the condensed carbon nitride and photocatalytic sites from the metalloporphyrins.This synergetic particle system effectively initiates efficient charge separation and transport and exhibits excellent photocatalytic activity for CO2 reduction.The CO production rate can reach up to 57μmol/(g·h)with a selectivity of 79%over competing H2 evolution.Controlled experiments demonstrate that the combination of light harvesting with photocatalytic activity via covalent assembly is crucial for the high photocatalytic activity.Due to effective charge separation and transfer,the resultant nanoparticle photocatalysts show exceptional photo stability against photo-corrosion under light irradiation,enabling for long-term utilization.This research opens a new way for the development of stable,effective nanoparticle photocatalysts using naturally abundant porphyrin pigments.
文摘In order to broaden the absorption range of graphitic carbon nitride,one of the common methods is to couple the well-known photosensitizer porphyrin with graphitic carbon nitride through van der Waals weak in teractions.To date,to combine porphyrin with graphitic carbon nitridethrough covalent in teractions has not been settled.In this work,through rational molecular design,we successfully in corporated porphyrininto the matrixes of graphitic carbon nitride by covale nt bonding via on expot thermal copolymerization.The resulta nt material not only can wide nthe absorption range but also possess the enlarged specific surface area and construction intramolecular heterojunctions which can contributeto improve electron-holes separation efficiency.The resultant photocatalyst exhibited enhanced H2 production rate(7.6 mmol·g^-1·h^-1)and withthe apparent quantum efficiency(AQE)of 13.3%at 450 nm.At the same time,this method opens a way to fabricate graphitic carb on nitridenano sheets via bottom-up strategy.
基金This work was supported by the National Natural Science Foundation of China(91545103)Shu Guang Project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation(10SG30)the Fundamental Research Funds for the Central Universities(222201717003)~~
文摘Paramagnetic polymer microspheres were synthesized by the inverse suspension polymerizationmethod through polymerization of glycidyl methacrylate,ally glycidyl ether and methacrylamide onthe surface of silica‐coated Fe3O4nanoparticles using N,N’‐methylene‐bis(acrylamide)as across‐linking agent.Penicillin G acylase(PGA)was covalently immobilized on the surface of theparamagnetic microspheres by reacting the amino groups of the PGA molecules with the epoxygroups of the paramagnetic polymer microspheres.The effect of the SiO2coating and the amount ofparamagnetic Fe3O4nanoparticles on the initial activity and the operational stability of the immobilizedPGA was investigated.The results indicated that SiO2played an important role in the polymerization process and paramagnetic polymer microspheres with a SiO2‐coated Fe3O4nanoparticles mass content of7.5%are an optimal support material for PGA immobilization.Immobilized PGA on the paramagnetic polymer microspheres shows a high initial activity of430U/g(wet)and retains99%of its initial activity after recycling10times.Furthermore,immobilized PGA exhibits high thermal stability,pH stability and excellent reusability,which can be rapidly recycled by the aid of magnet.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.
基金the financial support from the National Natural Science Foundation of China (52002356)the China Postdoctoral Science Foundation (2020M672269)the National Key R&D program of China (2019YFA0706802)
文摘In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving force.Among them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis process.The hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully constructed.The PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response stability.Furthermore,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.
基金supported by the National Natural Science Foundation of China(No.22175075).
文摘Due to the various pH liquid environment in nature,the pH-responsive lubricating hydrogel is widely investigated and developed for tissue interface substitute.However,the applied liquid environment will lead to poor mechanical property and weaken the pH-responsive capability.In this work,a carbon dotsenhanced pH-responsive lubricating hydrogel is developed by combining a pH-responsive section of dynamic PVA-borax network into a PAAm covalent polymer network.The formed hydrogel presents a partial gel-sol transition under controlled pH environments.At low pH environments(<6.0),the formed lubricating layer originated from dynamic disassembly of PVA-borax hydrogel,and brings the lubricating properties on the hydrogel surface.Moreover,the mechanical strength and lubrication properties are well promoted by introducing the carbon dots into the hydrogel,the blue sol layer can be observed more visually under the fluorescence microscope.The pH-response also exhibits well reversibility.The prepared hydrogel broadens the idea for designing pH-responsive soft materials for soft lubricating actuator or robot.
基金supported by the National Natural Science Foundation of China(Grant No.22179037)the Fundamental Research Funds for the Central Universities.Thanks for the financial support of‘Zhang Jiangshu’cultivation program.The authors declare no competing interests.
文摘Charge-transporting layers(CTLs)are important in determining the performance and stability of perovskite solar cells(PSCs).Recently,there has been considerable use of self-assembled monolayers(SAMs)as charge-selective contacts,especially for hole-selective SAMs in inverted PSCs as well as perovskite involving tandem solar cells.The SAM-based charge-selective contact shows many advantages over traditional thin-film organic/inorganic CTLs,including reduced cost,low optical and electric loss,conformal coating on a rough substrate,simple deposition on a large-area substrate and easy modulation of energy levels,molecular dipoles and surface properties.The incorporation of various hole-selective SAMs has resulted in high-efficiency single junction and tandem solar cells.This topical review summarizes both the advantages and challenges of SAM-based charge-selective contacts,and discusses the potential direction for future studies.
基金support by the NSFC Nos.51972156,51872131,51672117,51672118,22209055CPSF No.2022M721330Distin-guished Professor of Liaoning Province(2017)are acknowledged.
文摘Si is a promising anode material for lithium-ion batteries owing to its high theoretical capacity.How-ever,large stress during(de)lithiation induces severe structural pulverization,electrical contact failure,and unstable solid-electrolyte interface,which hampers the practical application of Si anode.Herein,a Si-based anode with a hierarchical pomegranate-structure(HPS-Si)was designed to modulate the stress variation,and a sub-micronized Si-based sphere was assembled by the nano-sized Si nanospheres with sub-nanometer-sized multi-phase modification of the covalently linked SiO_(2-x),SiC,and carbon.The sub-micronized HPS-Si stacked with Si nanospheres can avoid agglomerates during cycling due to the high surface energy of nanomaterials.Meanwhile,the reasonable pore structure from SiO_(2) reduction owing to density difference is enough to accommodate the limited volume expansion.The Si spheres with a size of about 50 nm can prevent self-cracking.SiO_(2-x),and SiC as flexible and rigid layers,have been syner-gistically used to reduce the surface stress of conductive carbon layers to avoid cracking.The covalent bonding immensely strengthens the link of the modification with Si nanospheres,thus resisting stress effects.Consequently,a full cell comprising an HPS-Si anode and a LiCoO_(2) cathode achieved an energy density of 415 Wh kg^(-1) with a capacity retention ratio of 87.9%after 300 cycles based on the active ma-terials.It is anticipated that the hierarchical pomegranate-structure design can provide inspiring insights for further studies of the practical application of silicon anode.
基金supported by the National Natural Science Foundation of China(Grant Nos.:82073814,81973291,82122066,and 82003909)the Rising-Star Program of Shanghai Science and Technology Committee(Grant No.:19QA1411500).
文摘Astragali Radix(AR)is a clinically used herbal medicine with multiple immunomodulatory activities that can strengthen the activity and cytotoxicity of natural killer(NK)cells.However,owing to the complexity of its composition,the specific active ingredients in AR that act on NK cells are not clear yet.Cell membrane chromatography(CMC)is mainly used to screen the active ingredients in a complex system of herbal medicines.In this study,a new comprehensive two-dimensional(2D)NK-92MI CMC/C18 column/time-of-flight mass spectrometry(TOFMS)system was established to screen for potential NK cell activators.To obtain a higher column efficiency,3-mercaptopropyltrimethoxysilane-modified silica was synthesized to prepare the NK-92MI CMC column.In total,nine components in AR were screened from this system,which could be washed out from the NK-92MI/CMC column after 10 min,and they showed good affinity for NK-92MI/CMC column.Two representative active compounds of AR,isoastragaloside Ⅰ and astragaloside IV,promoted the killing effect of NK cells on K562 cells in a dose-dependent manner.It can thus suggest that isoastragaloside Ⅰ and astragaloside Ⅳ are the main immunomodulatory components of AR.This comprehensive 2D NK-92MI CMC analytical system is a practical method for screening immune cell activators from other herbal medicines with immunomodulatory effects.
