Well aligned quasi-straight single-walled carbon nanotubes (SWCNTs) and straight SWCNTs bundle have been prepared in large scale by anode-arc vaporization of gr aphite with metallic catalysts. Various parameters such ...Well aligned quasi-straight single-walled carbon nanotubes (SWCNTs) and straight SWCNTs bundle have been prepared in large scale by anode-arc vaporization of gr aphite with metallic catalysts. Various parameters such as the catalyst preparat ion, the kinds and pressure of the buffer gases, the quantity of anode-arc curre nt intensity, and the method of purification have been examined. The influence o f these parameters on the deposited carbon yield is reported, together with obse rvations of the produced material. Improvement in synthetic techniques has resul ted in the optimal conditions for the production of large quantities of high qua lity SWCNTs in our semi-continuous synthesis method. The formation of carbon nan otubes (CNTs) was studied briefly in this paper. Owing to the magnetic pinching effect of arc current, the CNTs arrange in parallel lines along the arc current direction.展开更多
A series of Ni/Cu/Al catalyst samples were prepared by the co-precipitation method. Carbon nanotubes with large inner diameters are successfully synthesized from methane on Ni/Cu/Al catalyst by adding sodium carbonate...A series of Ni/Cu/Al catalyst samples were prepared by the co-precipitation method. Carbon nanotubes with large inner diameters are successfully synthesized from methane on Ni/Cu/Al catalyst by adding sodium carbonate. The effects of the copper content and amounts of sodium carbonate on the morphology and microstructures of carbon nanotubes were investigated by CO adsorption and TEM technique. The experimental results showed that copper can influence both the catalytic activity and catalyst life. Best result was obtained when the copper content was 15%. Addition of sodium carbonate favors the formation of carbon nanotubes with large inner diameters. The growth mechanism of carbon nanotubes with large inner diameter is discussed.展开更多
Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In th...Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed.展开更多
A series of Ni-La-Mg catalyst samples were prepared by citric acid complex method, and carbon nanotubes were synthesized by catalytic decomposition of CH4 on these catalysts. The effects of the citric acid concentrati...A series of Ni-La-Mg catalyst samples were prepared by citric acid complex method, and carbon nanotubes were synthesized by catalytic decomposition of CH4 on these catalysts. The effects of the citric acid concentration and the activation temperature on catalytic activity were investigated by CO adsorption, TEM and XRD techniques. The experimental results showed that the particle size of the catalysts prepared through gel auto-combustion varied with the concentration of citric acid. Therefore carbon nanotubes with different diameters were obtained correspondingly. The effect of activation temperature on the activity of catalyst was negligible from 500 to 700 ℃, but it became pronounced at lower or higher temperatures.展开更多
This paper provides an extension to the earlier work wherein a comparison between different models that had studied the effects of several parameters scaling on the performance of carbon nano tube field-effect transis...This paper provides an extension to the earlier work wherein a comparison between different models that had studied the effects of several parameters scaling on the performance of carbon nano tube field-effect transistors was presented. The evaluation for the studied models, with regard to the scaling effects, was to determine those which best reflect the very essence of carbon nano-tube technologies. Whereas the models subject this comparison （Fettoy, Roy, Stanford, and Southampton） were affected to varying degrees due to such parametric variations, the Stanford model was shown as still being valid for a wide range of chiralities and diameter sizes; a model that is also applicable for circuit simulations. In this paper, we present a comparative assessment of the various models subject to the study with regard to the effect of incorporating multiple carbon nanotubes in the channel region. We also assess the effect of oxide thickness on transistor performance in terms of the supply voltage threshold effects. Results leveraging our findings in this ongoing research endeavor reveal that many research efforts were not efficient to high degree due to high delay and not valid for circuit simulations.展开更多
In this paper,we present a novel method to fluorescently label magnetic carbon nanotubes by combining a non-ionic surfactant Tween 20 and a fluorescein isothiocyanate(FITC) commonly used in biological experiments.The ...In this paper,we present a novel method to fluorescently label magnetic carbon nanotubes by combining a non-ionic surfactant Tween 20 and a fluorescein isothiocyanate(FITC) commonly used in biological experiments.The samples were characterized using transmission electron microscopy(TEM),UV-Vis absorption spectrum(UV-Vis),vibrating sample magnetometer(VSM) and fluorescence spectra(FL).展开更多
Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some h...Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some hydrogenated graphene layers nanostructures: relevance to the hydrogen storage problem;2) determination of thermodynamic characteristics of graphene hydrides;3) a treatment and interpretation of some recent STM, STS, HREELS/LEED, PES, ARPS and Raman spectroscopy data on hydrogensorbtion with epitaxial graphenes;4) on the physics of intercalation of hydrogen into surface graphene-like nanoblisters in pyrolytic graphite and epitaxial graphenes;5) on the physics of the elastic and plastic deformation of graphene walls in hydrogenated graphite nanofibers;6) on the physics of engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials, in the light of analysis of the Rodriguez-Baker extraordinary data and some others. These fundamental open questions may be solved within several years.展开更多
Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the p...Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the past few years,MXenes/carbon nanotubes(CNTs)-based hybrids have attracted extensive attention as an important catalyst in energy and environmental fields,due to their superior multifunctions and mechanical stability.This review aims to address the fabrication strategies,the identification of the enhancement mechanisms,and recent progress regarding the design and modification of MXenes/CNTs-based hybrids.A myriad of fabrication techniques have been systematically summarized,including mechanical mixing,spray drying,three-dimensional(3D)printing,self-assembly/in-situ growth,freeze drying,templating,hydrothermal methods,chemical vapor deposition(CVD),and rolling.Importantly,the identification of the enhancement mechanisms was thoroughly discussed from the two dimensions of theoretical simulations and in-situ analysis.Moreover,the recent advancements in profound applications of MXenes/CNTs-based hybrids have also been carefully revealed,including energy storage devices,sensors,water purification systems,and microwave absorption.We also underscore anticipated challenges related to their fabrication,structure,underlying mechanisms,modification approaches,and emergent applications.Consequently,this review offers insights into prospective directions and the future trajectory for these promising hybrids.It is expected that this review can inspire new ideas or provide new research methods for future studies.展开更多
Due to unique and excellent properties,carbon nanotubes(CNTs)are expected to become the next-generation critical engineering mechanical and energy storage materials,which will play a key role as building blocks in aer...Due to unique and excellent properties,carbon nanotubes(CNTs)are expected to become the next-generation critical engineering mechanical and energy storage materials,which will play a key role as building blocks in aerospace,military equipment,communication sensing,and other cutting-edge fields.For practical application,the assembled macrostructures from individual CNTs are the common paradigms such as fibers or films.As the main representative,CNT films can not only retain the unique properties of their CNTs components,but also are more likely for mass-production than other macrostructures.Therefore,in this review,we focus on preparation of CNT films and discuss their emerging applications in the field of mechanical and electrochemical energy storage/conversion.Firstly,different preparation processes are systematically summarized.Then we introduce some typical strategies to improve their mechanical performances besides strengthening mechanism.Based on the progress of mass-production and performance optimization,we further discuss their potential utilization in mechanical and electrochemical energy storage/conversion devices.Finally,future perspectives for the development of CNT films in both production and application are proposed.We hope that this review will shed light on the preparation/assembly of CNT films and integrated application of excellent properties from individual to macroscopic dimensions.Moreover,the preparation and cross-scale application paradigms of CNT films also offer a good model for other macroscopic ordered assemblies of one-dimensional nanomaterials.展开更多
Carbon nanotubes exhibit many unique intrinsic physical and chemical properties and have been intensively explored for biological and biomedical applications in the past few years.In this comprehensive review,we summa...Carbon nanotubes exhibit many unique intrinsic physical and chemical properties and have been intensively explored for biological and biomedical applications in the past few years.In this comprehensive review,we summarize the main results from our and other groups in this field and clarify that surface functionalization is critical to the behavior of carbon nanotubes in biological systems.Ultrasensitive detection of biological species with carbon nanotubes can be realized after surface passivation to inhibit the non-specific binding of biomolecules on the hydrophobic nanotube surface.Electrical nanosensors based on nanotubes provide a label-free approach to biological detection.Surface-enhanced Raman spectroscopy of carbon nanotubes opens up a method of protein microarray with detection sensitivity down to 1 fmol/L.In vitro and in vivo toxicity studies reveal that highly water soluble and serum stable nanotubes are biocompatible,nontoxic,and potentially useful for biomedical applications.In vivo biodistributions vary with the functionalization and possibly also size of nanotubes,with a tendency to accumulate in the reticuloendothelial system(RES),including the liver and spleen,after intravenous administration.If well functionalized,nanotubes may be excreted mainly through the biliary pathway in feces.Carbon nanotube-based drug delivery has shown promise in various In vitro and in vivo experiments including delivery of small interfering RNA(siRNA),paclitaxel and doxorubicin.Moreover,single-walled carbon nanotubes with various interesting intrinsic optical properties have been used as novel photoluminescence,Raman,and photoacoustic contrast agents for imaging of cells and animals.Further multidisciplinary explorations in this field may bring new opportunities in the realm of biomedicine.展开更多
Two novel heterogeneous nickel a-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by co...Two novel heterogeneous nickel a-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by covalent attachment of the acenaphthenic ligand core to amine functionalized MWCNT ligand arms through diimine bonding and further nickel dibromide chelation. The prepared catalysts were fully characterized and their structures and supporting efficiencies were determined. Single or double introduction of the MWCNTs through their ends or sidewall（s） in the catalytic system, as a ligand, influenced the catalytic performance, microstructure and morphology of obtained polyethylenes. MWCNT sidewall bonding to para-aryl position of the tetramethylphenyl moiety performed as more electron-donating ligand than MWCNT ends linked to the imine bond and protected the catalytic system to retain its activity. This character resulted in the maintenance of the resulting polymer topology at elevated temperatures so that the catalytic activity and the obtained polymer melting points remained around 110 g PE·mmol^-1 Ni·h^-1 and 123 ℃ in all polymerization temperatures respectively. In polymerization trials, molecular weight fall against temperature was not as sharp as what had been observed in sequentially prepared catalysts insofar as the molecular weight of resultant polymer at 60 ℃ reached to 310000 g·mol^-1 which was close to the highest value had been reported at 30 ℃ for sequentially prepared catalysts. TEM observations showed the presence of the stopped-growth polymer chains due to geometrical constrains or ligand debonding for both catalytic systems.展开更多
As one kind of promising zero-dimensional nanomaterials,carbon dots(CDs)have attracted extensive attention recently in green chemistry and engineering on account of their excellent properties,such as water solubility,...As one kind of promising zero-dimensional nanomaterials,carbon dots(CDs)have attracted extensive attention recently in green chemistry and engineering on account of their excellent properties,such as water solubility,comparable optical properties,low toxicity,and surface passivation and functionalization.One direction in CDs research is to prepare these materials with low cost and high quantum yield(QY).As an alternative protocol,utilizing biomass or its derivatives as the raw materials would create more chances to produce biocompatible and cheap CDs.Due to the good solvability for biomass,various ionic liquids(ILs)have been tested in the field of biomass derived CDs,which are found multiple roles of solvation and surface functionalization in the synthesis and application of these materials.This review will not cover the whole developed picture of CDs,but just summarizes the latest research progresses on the ILs based preparation and applications of CDs from biomass and its derivatives.The roles of ILs displayed in the corresponding processing including intensification and surface modification were discussed in detail.At the end of this review,an outlook was provided to highlight the challenges and opportunities associated with this interesting and promising area.展开更多
Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-...Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite.The capacity reaches 1233.6 mA h g-1 at a current density of 100 mA g-1 for the first discharge,and it can still maintain a capacity of 633.1mA h g-1 after 100 charge-discharge cycles.The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions,and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.展开更多
Activated carbon fiber is one kind of important adsorption materials. These novel fibrous adsorbents have high specific surface areas or abundant functional groups, which make them have greater adsorption/desorption r...Activated carbon fiber is one kind of important adsorption materials. These novel fibrous adsorbents have high specific surface areas or abundant functional groups, which make them have greater adsorption/desorption rates and larger adsorption capacities than other adsorbents. They can be prepared as bundle, paper, cloth and felt to meet various technical requirement. They also show reduction property. In this paper the latest progress on the studies of the preparation and adsorption properties of activated carbon fibers is reviewed. The application of these materials in drinking water purification, environmental control, resource recovery, chemical industry, and in medicine and health care is also presented.展开更多
Graphene and carbon nanotube(CNT) are representative carbon nanomaterials which have aroused numerous research interest due to their extraordinary material properties and promising application potentials,especially in...Graphene and carbon nanotube(CNT) are representative carbon nanomaterials which have aroused numerous research interest due to their extraordinary material properties and promising application potentials,especially in the energy storage and conversion areas.However,the agglomeration happening in these materials has largely blocked their applications.Hybridization of CNT with graphene can,on one hand,prevent the agglomeration behavior,on the other hand,generate a synergistic effect between them with enhanced physical and chemical properties.There have been many studies conducted to find out the suitable approaches to synthesize graphene/CNT composites,and realize the application potentials of these structures.Based on the recent advances,this paper reviews the current research progress that has been achieved in synthesizing graphene/CNT composites,and the energy-related applications.Through this review,we aim at stimulating more significant research on this subject.展开更多
基金This work was supported by Natural Science Foundation of Gansu provincethe Tackle Key Problems Foundation of Gansu pronince,China.
文摘Well aligned quasi-straight single-walled carbon nanotubes (SWCNTs) and straight SWCNTs bundle have been prepared in large scale by anode-arc vaporization of gr aphite with metallic catalysts. Various parameters such as the catalyst preparat ion, the kinds and pressure of the buffer gases, the quantity of anode-arc curre nt intensity, and the method of purification have been examined. The influence o f these parameters on the deposited carbon yield is reported, together with obse rvations of the produced material. Improvement in synthetic techniques has resul ted in the optimal conditions for the production of large quantities of high qua lity SWCNTs in our semi-continuous synthesis method. The formation of carbon nan otubes (CNTs) was studied briefly in this paper. Owing to the magnetic pinching effect of arc current, the CNTs arrange in parallel lines along the arc current direction.
基金Supported by National Natural Science Foundation of China and Technology Bureau of Jiangxi province
文摘A series of Ni/Cu/Al catalyst samples were prepared by the co-precipitation method. Carbon nanotubes with large inner diameters are successfully synthesized from methane on Ni/Cu/Al catalyst by adding sodium carbonate. The effects of the copper content and amounts of sodium carbonate on the morphology and microstructures of carbon nanotubes were investigated by CO adsorption and TEM technique. The experimental results showed that copper can influence both the catalytic activity and catalyst life. Best result was obtained when the copper content was 15%. Addition of sodium carbonate favors the formation of carbon nanotubes with large inner diameters. The growth mechanism of carbon nanotubes with large inner diameter is discussed.
文摘Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed.
基金National Nature Science Foundation of China and Science and Technology Bureau of Jiangxi province
文摘A series of Ni-La-Mg catalyst samples were prepared by citric acid complex method, and carbon nanotubes were synthesized by catalytic decomposition of CH4 on these catalysts. The effects of the citric acid concentration and the activation temperature on catalytic activity were investigated by CO adsorption, TEM and XRD techniques. The experimental results showed that the particle size of the catalysts prepared through gel auto-combustion varied with the concentration of citric acid. Therefore carbon nanotubes with different diameters were obtained correspondingly. The effect of activation temperature on the activity of catalyst was negligible from 500 to 700 ℃, but it became pronounced at lower or higher temperatures.
文摘This paper provides an extension to the earlier work wherein a comparison between different models that had studied the effects of several parameters scaling on the performance of carbon nano tube field-effect transistors was presented. The evaluation for the studied models, with regard to the scaling effects, was to determine those which best reflect the very essence of carbon nano-tube technologies. Whereas the models subject this comparison （Fettoy, Roy, Stanford, and Southampton） were affected to varying degrees due to such parametric variations, the Stanford model was shown as still being valid for a wide range of chiralities and diameter sizes; a model that is also applicable for circuit simulations. In this paper, we present a comparative assessment of the various models subject to the study with regard to the effect of incorporating multiple carbon nanotubes in the channel region. We also assess the effect of oxide thickness on transistor performance in terms of the supply voltage threshold effects. Results leveraging our findings in this ongoing research endeavor reveal that many research efforts were not efficient to high degree due to high delay and not valid for circuit simulations.
文摘In this paper,we present a novel method to fluorescently label magnetic carbon nanotubes by combining a non-ionic surfactant Tween 20 and a fluorescein isothiocyanate(FITC) commonly used in biological experiments.The samples were characterized using transmission electron microscopy(TEM),UV-Vis absorption spectrum(UV-Vis),vibrating sample magnetometer(VSM) and fluorescence spectra(FL).
文摘Herein, some fundamental open questions on engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials are considered, namely: 1) on thermodynamic stability and related characteristics of some hydrogenated graphene layers nanostructures: relevance to the hydrogen storage problem;2) determination of thermodynamic characteristics of graphene hydrides;3) a treatment and interpretation of some recent STM, STS, HREELS/LEED, PES, ARPS and Raman spectroscopy data on hydrogensorbtion with epitaxial graphenes;4) on the physics of intercalation of hydrogen into surface graphene-like nanoblisters in pyrolytic graphite and epitaxial graphenes;5) on the physics of the elastic and plastic deformation of graphene walls in hydrogenated graphite nanofibers;6) on the physics of engineering of “super” hydrogen sorption (storage) in carbonaceous nanomaterials, in the light of analysis of the Rodriguez-Baker extraordinary data and some others. These fundamental open questions may be solved within several years.
基金supported by the National Natural Science Foundation of China(No.62004143)the Key R&D Program of Hubei Province(No.2022BAA084).
文摘Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the past few years,MXenes/carbon nanotubes(CNTs)-based hybrids have attracted extensive attention as an important catalyst in energy and environmental fields,due to their superior multifunctions and mechanical stability.This review aims to address the fabrication strategies,the identification of the enhancement mechanisms,and recent progress regarding the design and modification of MXenes/CNTs-based hybrids.A myriad of fabrication techniques have been systematically summarized,including mechanical mixing,spray drying,three-dimensional(3D)printing,self-assembly/in-situ growth,freeze drying,templating,hydrothermal methods,chemical vapor deposition(CVD),and rolling.Importantly,the identification of the enhancement mechanisms was thoroughly discussed from the two dimensions of theoretical simulations and in-situ analysis.Moreover,the recent advancements in profound applications of MXenes/CNTs-based hybrids have also been carefully revealed,including energy storage devices,sensors,water purification systems,and microwave absorption.We also underscore anticipated challenges related to their fabrication,structure,underlying mechanisms,modification approaches,and emergent applications.Consequently,this review offers insights into prospective directions and the future trajectory for these promising hybrids.It is expected that this review can inspire new ideas or provide new research methods for future studies.
基金supported by the National Natural Science Foundation of China(Nos.22108155,LY23B060003,and T2350004)the Ministry of Science and Technology of China(No.2022YFA1203301).
文摘Due to unique and excellent properties,carbon nanotubes(CNTs)are expected to become the next-generation critical engineering mechanical and energy storage materials,which will play a key role as building blocks in aerospace,military equipment,communication sensing,and other cutting-edge fields.For practical application,the assembled macrostructures from individual CNTs are the common paradigms such as fibers or films.As the main representative,CNT films can not only retain the unique properties of their CNTs components,but also are more likely for mass-production than other macrostructures.Therefore,in this review,we focus on preparation of CNT films and discuss their emerging applications in the field of mechanical and electrochemical energy storage/conversion.Firstly,different preparation processes are systematically summarized.Then we introduce some typical strategies to improve their mechanical performances besides strengthening mechanism.Based on the progress of mass-production and performance optimization,we further discuss their potential utilization in mechanical and electrochemical energy storage/conversion devices.Finally,future perspectives for the development of CNT films in both production and application are proposed.We hope that this review will shed light on the preparation/assembly of CNT films and integrated application of excellent properties from individual to macroscopic dimensions.Moreover,the preparation and cross-scale application paradigms of CNT films also offer a good model for other macroscopic ordered assemblies of one-dimensional nanomaterials.
文摘Carbon nanotubes exhibit many unique intrinsic physical and chemical properties and have been intensively explored for biological and biomedical applications in the past few years.In this comprehensive review,we summarize the main results from our and other groups in this field and clarify that surface functionalization is critical to the behavior of carbon nanotubes in biological systems.Ultrasensitive detection of biological species with carbon nanotubes can be realized after surface passivation to inhibit the non-specific binding of biomolecules on the hydrophobic nanotube surface.Electrical nanosensors based on nanotubes provide a label-free approach to biological detection.Surface-enhanced Raman spectroscopy of carbon nanotubes opens up a method of protein microarray with detection sensitivity down to 1 fmol/L.In vitro and in vivo toxicity studies reveal that highly water soluble and serum stable nanotubes are biocompatible,nontoxic,and potentially useful for biomedical applications.In vivo biodistributions vary with the functionalization and possibly also size of nanotubes,with a tendency to accumulate in the reticuloendothelial system(RES),including the liver and spleen,after intravenous administration.If well functionalized,nanotubes may be excreted mainly through the biliary pathway in feces.Carbon nanotube-based drug delivery has shown promise in various In vitro and in vivo experiments including delivery of small interfering RNA(siRNA),paclitaxel and doxorubicin.Moreover,single-walled carbon nanotubes with various interesting intrinsic optical properties have been used as novel photoluminescence,Raman,and photoacoustic contrast agents for imaging of cells and animals.Further multidisciplinary explorations in this field may bring new opportunities in the realm of biomedicine.
文摘Two novel heterogeneous nickel a-diimine based polymerization catalysts, containing MWCNT as the main ligand, were synthesized by novel in situ catalyst preparation technique. The in situ synthesis was performed by covalent attachment of the acenaphthenic ligand core to amine functionalized MWCNT ligand arms through diimine bonding and further nickel dibromide chelation. The prepared catalysts were fully characterized and their structures and supporting efficiencies were determined. Single or double introduction of the MWCNTs through their ends or sidewall（s） in the catalytic system, as a ligand, influenced the catalytic performance, microstructure and morphology of obtained polyethylenes. MWCNT sidewall bonding to para-aryl position of the tetramethylphenyl moiety performed as more electron-donating ligand than MWCNT ends linked to the imine bond and protected the catalytic system to retain its activity. This character resulted in the maintenance of the resulting polymer topology at elevated temperatures so that the catalytic activity and the obtained polymer melting points remained around 110 g PE·mmol^-1 Ni·h^-1 and 123 ℃ in all polymerization temperatures respectively. In polymerization trials, molecular weight fall against temperature was not as sharp as what had been observed in sequentially prepared catalysts insofar as the molecular weight of resultant polymer at 60 ℃ reached to 310000 g·mol^-1 which was close to the highest value had been reported at 30 ℃ for sequentially prepared catalysts. TEM observations showed the presence of the stopped-growth polymer chains due to geometrical constrains or ligand debonding for both catalytic systems.
基金supported by the Startup Foundation of Beijing Institute of Technology,China(3160011181808).
文摘As one kind of promising zero-dimensional nanomaterials,carbon dots(CDs)have attracted extensive attention recently in green chemistry and engineering on account of their excellent properties,such as water solubility,comparable optical properties,low toxicity,and surface passivation and functionalization.One direction in CDs research is to prepare these materials with low cost and high quantum yield(QY).As an alternative protocol,utilizing biomass or its derivatives as the raw materials would create more chances to produce biocompatible and cheap CDs.Due to the good solvability for biomass,various ionic liquids(ILs)have been tested in the field of biomass derived CDs,which are found multiple roles of solvation and surface functionalization in the synthesis and application of these materials.This review will not cover the whole developed picture of CDs,but just summarizes the latest research progresses on the ILs based preparation and applications of CDs from biomass and its derivatives.The roles of ILs displayed in the corresponding processing including intensification and surface modification were discussed in detail.At the end of this review,an outlook was provided to highlight the challenges and opportunities associated with this interesting and promising area.
基金supported by the National Natural Science Foundation of China(Grant Nos.11179038 and 10974073)the Specialized Re-search Fund for the Doctoral Program of Higher Education(Grant No.20120211130005)
文摘Tubular nanocomposite with interconnected MnO2 nanoflakes coated on MWCNTs(MWCNTs@MnO2)was fabricated by an aqueous solution method at 80°C.Scanning electron microscopy,X-ray diffraction and galvanostatic charge-discharge tests were used to characterize the structures and electrochemical performances of the as-prepared nanocomposite.The capacity reaches 1233.6 mA h g-1 at a current density of 100 mA g-1 for the first discharge,and it can still maintain a capacity of 633.1mA h g-1 after 100 charge-discharge cycles.The results show that MWCNTs with good electrical conductivity as anchors of MnO2 can provide fast electron transport channels for MnO2 in the electrochemical reactions,and the as-prepared MWCNTs@MnO2 nanocomposite is a potential anode material for lithium ion batteries.
基金NSFC (50073029) and Natural Science Foundation of Guangdong province (001276)
文摘Activated carbon fiber is one kind of important adsorption materials. These novel fibrous adsorbents have high specific surface areas or abundant functional groups, which make them have greater adsorption/desorption rates and larger adsorption capacities than other adsorbents. They can be prepared as bundle, paper, cloth and felt to meet various technical requirement. They also show reduction property. In this paper the latest progress on the studies of the preparation and adsorption properties of activated carbon fibers is reviewed. The application of these materials in drinking water purification, environmental control, resource recovery, chemical industry, and in medicine and health care is also presented.
文摘Graphene and carbon nanotube(CNT) are representative carbon nanomaterials which have aroused numerous research interest due to their extraordinary material properties and promising application potentials,especially in the energy storage and conversion areas.However,the agglomeration happening in these materials has largely blocked their applications.Hybridization of CNT with graphene can,on one hand,prevent the agglomeration behavior,on the other hand,generate a synergistic effect between them with enhanced physical and chemical properties.There have been many studies conducted to find out the suitable approaches to synthesize graphene/CNT composites,and realize the application potentials of these structures.Based on the recent advances,this paper reviews the current research progress that has been achieved in synthesizing graphene/CNT composites,and the energy-related applications.Through this review,we aim at stimulating more significant research on this subject.
