Synthesis of carbon nanotubes （CNTs） below 600℃ using supporting catalyst chemical vapor deposition method was reported by many research groups. However, the floating catalyst chemical vapor deposition received les...Synthesis of carbon nanotubes （CNTs） below 600℃ using supporting catalyst chemical vapor deposition method was reported by many research groups. However, the floating catalyst chemical vapor deposition received less attention due to imperfect nanotubes produced. In this work, the effects of varying the preheating temperature on the synthesis of CNT were investigated. The reaction temperature was set at 570℃. The preheating set temperature was varied from 150 to 400℃ at 50℃ interval. Three O-ring shape heating mantels were used as heating source for the preheater. In situ monitoring device was used to observe the temperature profile in the reactor. Benzene and ferrocene were used as the carbon source and catalyst precursor, respectively. Vertically aligned CNTs were synthesized when the preheating temperature was set at 400℃. When the preheating temperature was increased up to 400℃, both the length and the alignment of CNTs produced were improved.展开更多
A strategy to prepare horizontally aligned single-walled carbon nanotubes(SWNTs) at moderate temperatures(≤600 ℃) were developed.Using ferocene as the catalyst precursor,Fe nanoparticles are formed in the gaseous ph...A strategy to prepare horizontally aligned single-walled carbon nanotubes(SWNTs) at moderate temperatures(≤600 ℃) were developed.Using ferocene as the catalyst precursor,Fe nanoparticles are formed in the gaseous phase and catalyze the nucleation and growth of SWNTs in situ.Then the resultant SWNTs are deposited onto the substrates downstream and aligned by the surface lattice of the ST-cut single crystal quartz.The preparation of SWNT arrays at moderate temperatures is important for combining the tube growth with device fabrication.展开更多
A novel photocatalyst based on TiO2-PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline（PANI）-modified TiO2 on cork. The TiO2-PANI/Cor...A novel photocatalyst based on TiO2-PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline（PANI）-modified TiO2 on cork. The TiO2-PANI/Cork catalyst shows the unique feature of floating on the water surface. The as-synthesized catalyst was characterized by X-ray diffraction（XRD）,scanning electron micrograph（SEM）, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, Fourier transform infrared spectroscopy（FT-IR）, UV-vis diffuse reflectance spectra（UV-vis DRS） and the Brunauer-Emmett-Teller（BET） surface area analysis. Characterization suggested the formation of anatase highly dispersed on the cork surface. The prepared floating photocatalyst showed high efficiency for the degradation of methyl orange dye and other organic pollutants under solar irradiation and constrained conditions, i.e., no-stirring and no-oxygenation. The TiO2-PANI/Cork floating photocatalyst can be reused for at least four consecutive times without significant decrease of the degradation efficiency.展开更多
The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor depositio...The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor deposition(FCCVD) requires a large amount of non-renewable carbon sources. Here, the continuous production of highly graphitized CNT yarns from biomass tannic acid(TA) is reported. The chelation of TA and catalyst promotes the rapid cracking of biomass into carbon source gas, and the pyrolysis cracking produces the reducing gas, which solves the problems of the continuous production of CNT yarns using biomass. Through simple twisting, the mechanical strength of CNT yarn can reach 886 ± 46 MPa, and the electrical conductivity and graphitization(IG/ID) can reach 2 × 10^(5)S m^(-1)and 6.3, respectively. This work presents a promising solution for the continuous preparation of CNT yarns based on green raw material.展开更多
We report a new scheme for fabrication of clean,suspended superconducting weak links from pristine single-walled carbon nanotubes(SWCNT).The SWCNTs were grown using the floating-catalyst chemical vapour deposition(FC-...We report a new scheme for fabrication of clean,suspended superconducting weak links from pristine single-walled carbon nanotubes(SWCNT).The SWCNTs were grown using the floating-catalyst chemical vapour deposition(FC-CVD)and directly deposited on top of prefabricated superconducting molybdenum-rhenium(MoRe)electrodes by thermophoresis at nearly ambient conditions.Transparent contacts to SWCNTs were obtained by vacuum-annealing the devices at 900℃,which enabled proximity-induced supercurrents up to 53 nA.SWCNT weak links fabricated on MoRe/palladium bilayer sustained supercurrents up to 0.4 nA after annealing at relatively low temperature of 220℃.The fabrication process does neither expose SWCNTs to lithographic chemicals,nor the contact electrodes to the harsh conditions of in situ CVD growth.Our scheme facilitates new experimental possibilities for hybrid superconducting devices.展开更多
Single-walled carbon nanotube(SWCNT)transparent conducting films(TCFs)are attracting increasing attention due to their exceptional optoelectronic properties.Toluene is a proposed carbon source for SWCNT synthesis,but ...Single-walled carbon nanotube(SWCNT)transparent conducting films(TCFs)are attracting increasing attention due to their exceptional optoelectronic properties.Toluene is a proposed carbon source for SWCNT synthesis,but the growth parameters of SWCNTs and their TCF optoelectronic performance(i.e.,sheet resistance versus transmittance)have been insufficiently evaluated.Here,we have for the first time reported a systematic study of the fabrication of high-performance SWCNT TCFs using toluene alone as the carbon source.The mechanisms behind each observed phenomenon were elucidated using optical and microscopy techniques.By optimizing the growth parameters,high yields of SWCNT TCFs exhibiting a considerably low sheet resistance of 57Ω/sq at 90%transmittance were obtained.This competitive optoelectronic performance is mainly attributable to long SWCNT bundles(mean length is 41.4μm)in the film.Additionally,a chirality map determined by electron diffraction displays a bimodal distribution of chiral angles divided at 15°,which is close to both armchair and zigzag edges.Our study paved the way towards scaled-up production of SWCNTs for the fabrication of high-performance TCFs for industrial applications.展开更多
基金supported by Research Universiti Grant,Universiti Putra Malaysia (Project No. RU01154)
文摘Synthesis of carbon nanotubes （CNTs） below 600℃ using supporting catalyst chemical vapor deposition method was reported by many research groups. However, the floating catalyst chemical vapor deposition received less attention due to imperfect nanotubes produced. In this work, the effects of varying the preheating temperature on the synthesis of CNT were investigated. The reaction temperature was set at 570℃. The preheating set temperature was varied from 150 to 400℃ at 50℃ interval. Three O-ring shape heating mantels were used as heating source for the preheater. In situ monitoring device was used to observe the temperature profile in the reactor. Benzene and ferrocene were used as the carbon source and catalyst precursor, respectively. Vertically aligned CNTs were synthesized when the preheating temperature was set at 400℃. When the preheating temperature was increased up to 400℃, both the length and the alignment of CNTs produced were improved.
基金supported by Ministry of Science and Technology of China(2016YFA0201904)the National Natural Science Foundation of China(21631002,U1632119)
文摘A strategy to prepare horizontally aligned single-walled carbon nanotubes(SWNTs) at moderate temperatures(≤600 ℃) were developed.Using ferocene as the catalyst precursor,Fe nanoparticles are formed in the gaseous phase and catalyze the nucleation and growth of SWNTs in situ.Then the resultant SWNTs are deposited onto the substrates downstream and aligned by the surface lattice of the ST-cut single crystal quartz.The preparation of SWNT arrays at moderate temperatures is important for combining the tube growth with device fabrication.
文摘A novel photocatalyst based on TiO2-PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline（PANI）-modified TiO2 on cork. The TiO2-PANI/Cork catalyst shows the unique feature of floating on the water surface. The as-synthesized catalyst was characterized by X-ray diffraction（XRD）,scanning electron micrograph（SEM）, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, Fourier transform infrared spectroscopy（FT-IR）, UV-vis diffuse reflectance spectra（UV-vis DRS） and the Brunauer-Emmett-Teller（BET） surface area analysis. Characterization suggested the formation of anatase highly dispersed on the cork surface. The prepared floating photocatalyst showed high efficiency for the degradation of methyl orange dye and other organic pollutants under solar irradiation and constrained conditions, i.e., no-stirring and no-oxygenation. The TiO2-PANI/Cork floating photocatalyst can be reused for at least four consecutive times without significant decrease of the degradation efficiency.
基金the support from the Science and Technology Commission of Shanghai Municipality (20JC1414900)the Joint Funds of the National Natural Science Foundation of China (U20A20257)+1 种基金the Program of Shanghai Academic/Technology Research Leader (20XD1433700)the International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality (20520740800)。
文摘The rapid growth of the demand for carbon nanotubes(CNTs) has greatly promoted their large-scale synthesis and development. However,the continuous production of CNT fibers by floating catalyst chemical vapor deposition(FCCVD) requires a large amount of non-renewable carbon sources. Here, the continuous production of highly graphitized CNT yarns from biomass tannic acid(TA) is reported. The chelation of TA and catalyst promotes the rapid cracking of biomass into carbon source gas, and the pyrolysis cracking produces the reducing gas, which solves the problems of the continuous production of CNT yarns using biomass. Through simple twisting, the mechanical strength of CNT yarn can reach 886 ± 46 MPa, and the electrical conductivity and graphitization(IG/ID) can reach 2 × 10^(5)S m^(-1)and 6.3, respectively. This work presents a promising solution for the continuous preparation of CNT yarns based on green raw material.
基金This work was supported by the Academy of Finland projects 314448(BOLOSE)312295(CoE,Quantum Technology Finland)as well as by ERC(grant no.670743)+3 种基金The research also received partial funding from the European Union Seventh Framework Program FP7 Nanosciences,Nanotechnologies,Materials and new Production Technologies(FP7/2007-2013)under Grant Agreement No.604472(IRENA project)the Aalto Energy Efficiency(AEF)Research Program through the MOPPI projectIn addition,the research was partially supported by the Academy of Finland(Luonnontieteiden ja Tekniikan Tutkimuksen Toimikunta)via projects 286546(DEMEC)and 292600(SUPER)as well as by TEKES Finland via projects 3303/31/2015(cNT-PV)and 1882/31/2016(FEDOC).
文摘We report a new scheme for fabrication of clean,suspended superconducting weak links from pristine single-walled carbon nanotubes(SWCNT).The SWCNTs were grown using the floating-catalyst chemical vapour deposition(FC-CVD)and directly deposited on top of prefabricated superconducting molybdenum-rhenium(MoRe)electrodes by thermophoresis at nearly ambient conditions.Transparent contacts to SWCNTs were obtained by vacuum-annealing the devices at 900℃,which enabled proximity-induced supercurrents up to 53 nA.SWCNT weak links fabricated on MoRe/palladium bilayer sustained supercurrents up to 0.4 nA after annealing at relatively low temperature of 220℃.The fabrication process does neither expose SWCNTs to lithographic chemicals,nor the contact electrodes to the harsh conditions of in situ CVD growth.Our scheme facilitates new experimental possibilities for hybrid superconducting devices.
基金funding from projects 286546(DEMEC)and 292600(SUPER)supported by the Academy of Finland,as well as projects 3303/31/2015(CNT-PV)and 1882/31/2016(FEDOC)supported by TEKES in Finland.
文摘Single-walled carbon nanotube(SWCNT)transparent conducting films(TCFs)are attracting increasing attention due to their exceptional optoelectronic properties.Toluene is a proposed carbon source for SWCNT synthesis,but the growth parameters of SWCNTs and their TCF optoelectronic performance(i.e.,sheet resistance versus transmittance)have been insufficiently evaluated.Here,we have for the first time reported a systematic study of the fabrication of high-performance SWCNT TCFs using toluene alone as the carbon source.The mechanisms behind each observed phenomenon were elucidated using optical and microscopy techniques.By optimizing the growth parameters,high yields of SWCNT TCFs exhibiting a considerably low sheet resistance of 57Ω/sq at 90%transmittance were obtained.This competitive optoelectronic performance is mainly attributable to long SWCNT bundles(mean length is 41.4μm)in the film.Additionally,a chirality map determined by electron diffraction displays a bimodal distribution of chiral angles divided at 15°,which is close to both armchair and zigzag edges.Our study paved the way towards scaled-up production of SWCNTs for the fabrication of high-performance TCFs for industrial applications.
