Nano-crystalline FeOOH particles （5-10 nm） have been uniformly mixed with electric matrix of single-walled carbon nanotubes （SWNTs） for forming FeOOH/SWNT composite via a facile ultrasonication method. Directly us...Nano-crystalline FeOOH particles （5-10 nm） have been uniformly mixed with electric matrix of single-walled carbon nanotubes （SWNTs） for forming FeOOH/SWNT composite via a facile ultrasonication method. Directly using the FeOOH/SWNT composite （containing 15 wt% SWNTs） as anode material for lithium battery enhances kinetics of the Li＋ insertion/extraction processes, thereby effectively improving re- versible capacity and cycle performance, which delivers a high reversible capacity of 758 mAh.g-1 under a current density of 400 mA.g-1 even after 180 cycles, being comparable with previous reports in terms of electrochemical performance for FeOOH anode. The good electrochemical performance should be ascribed to the small particle size and nano-crystalline of FeOOH, as well as the good electronic conductivity of SWNT matrix.展开更多
Single-wall carbon nanotubes （SWNTs） with high surface area were synthesized over nanoporous Co-Mo/MgO by a chemical vapor deposition （CVD） method. The SWNTs were used as catalyst support for selective hydrogenati...Single-wall carbon nanotubes （SWNTs） with high surface area were synthesized over nanoporous Co-Mo/MgO by a chemical vapor deposition （CVD） method. The SWNTs were used as catalyst support for selective hydrogenation of syngas to hydrocarbons. Here an extensive study of Fischer-Tropsch synthesis （FTS） on CNT-supported cobalt catalysts with different amounts of cobalt loading up to 40 wt% is reported. The catalysts were characterized by different methods including N2 adsorption-desorption, X-ray diffraction, hydrogen chemisorption, inductively coupled plasma （ICP） and temperature-programmed reduction. Enhancement of the reducibility of Co3O4 to CoO, CoO to Co° and small cobalt oxide particles, dispersion of the cobalt, and activity and selectivity of FTS were investigated and compared with a conventional support. The CNT supported catalysts achieve a high dispersion and high loading of the active metal, cobalt in particular, so that the bulk formation of cobalt metal, which tends to occur in conventional support, can be avoided. The results showed that the specific activity of CNT supported catalysts increase significantly （there is a two fold increase in CO Conversion per gram of the active metal） with respect to the conventional supported catalyst.展开更多
We report a theoretical study on the electronic structures of O2 chemisorbed on a（8,0） SWNT with different oxygen contents of 6.25,12.5 and 25%,respectively.On the basis of DFT calculations,we find that eight O2 mol...We report a theoretical study on the electronic structures of O2 chemisorbed on a（8,0） SWNT with different oxygen contents of 6.25,12.5 and 25%,respectively.On the basis of DFT calculations,we find that eight O2 molecules chemisorbed on the（8,0） SWNT aligned in the middle row of the circumference of the tube in proportional spacing way,is seen to become metallic,and a significant increase in conductivity is expected.There are different electronic structures of the functionalized systems related to different oxygen contents or O2 molecules＇ chemisorbed positions.展开更多
Conducting supporters of purified single-walled carbon nanotubes（SWNTs） and graphene oxide（GO）were used to confine pomegranate-structured Sn O2 nanospheres for forming SnO-GO-SWNT composites.As anode material for ...Conducting supporters of purified single-walled carbon nanotubes（SWNTs） and graphene oxide（GO）were used to confine pomegranate-structured Sn O2 nanospheres for forming SnO-GO-SWNT composites.As anode material for lithium ion batteries（LIBs）, this composite exhibits a stable and large reversible capacity together with an excellent rate capability. In addition, an analysis of the AC impedance spectroscopy has been used to confirm the enhanced mechanism for LIB performance. The improved electrochemical performance should be ascribed greatly to the reinforced synergistic effects between GO and SWNT networks, and their enhanced contribution of the conductivity. These results indicate that this composite has potential for utilization in high-rate and durable LIBs.展开更多
This paper reveals, by analyses of nitrogen cryo-adsorption isotherm, the energetic and structural heterogeneity of single-walled carbon nanotubes (SWNTs) which has a high hydrogen storage capacity. It was found that ...This paper reveals, by analyses of nitrogen cryo-adsorption isotherm, the energetic and structural heterogeneity of single-walled carbon nanotubes (SWNTs) which has a high hydrogen storage capacity. It was found that SWNTs had manifold pore structures and distributed surface energy. By comparison of the pore structures and energy distributions of SWNTs before and after hydrogen adsorption, it is preliminarily indicated that hydrogen adsorption occurred in micropores and mesopores with smaller diameter, and that the pores of different diameters determined different hydrogen adsorption processes and underwent different structure changes during hydrogen adsorption.展开更多
Helical amylose/SWNTs complexes (A/S-C) of various sizes, a single nanotube wrapped by amylose in particular, were demonstrated. The formation process of the helical A/S-C was further explained by a novel hierarchical...Helical amylose/SWNTs complexes (A/S-C) of various sizes, a single nanotube wrapped by amylose in particular, were demonstrated. The formation process of the helical A/S-C was further explained by a novel hierarchical self-assembly model, including the wrapping of amylose chains around SWNT and the hierarchical self-assembly of wrapped-SWNTs into the superstructural A/S-C. Besides the hydrophobic interaction, the hydrogen bonding also plays a certain role in the self-assembly process.展开更多
One dimensional(1 D) nanostructures have many possible applications in electronic, optical, and sensing devices associated with their nanosized lateral dimensions. In this regard, a general and bottom-up strategy to s...One dimensional(1 D) nanostructures have many possible applications in electronic, optical, and sensing devices associated with their nanosized lateral dimensions. In this regard, a general and bottom-up strategy to synthesize 1 D nanoparticle arrays and conductive nanowires with a facile structural/compositional control is highly desired. We herein report a protein-sheathed single walled carbon nanotube(SWNT) that satisfies the criteria for an ideal template to assemble micron-long gold nanoparticle(Au NP) linear arrays with high structural rigidity. The resulting Au NP array has minimized inter-particle gaps, which is especially useful to template the overgrowth of Ag, Pd, and Pd/Ag metals into continuous nanowires(Au@M, M=Ag, Pd, Ag/Pd). Our method successfully overcomes the incompatibility between carbon and metal materials, and the resulting superstructured metal nanowires have a tunable diameter below 100 nm and a shape closely replicating a SWNT. The Ag nanowires are composed of coalesced Au@Ag coreshell nanoparticles, while the Pd and Pd/Ag nanowires are made of very fine Pd nanocrystallites around the Au NP cores. These unique structural features are pivotal to various applications including surface enhanced Raman scattering(SERS), electrocatalysis, and gas sensors.展开更多
We reported the growth of horizontally aligned nitrogen-doped single-walled carbon nanotubes (SWNTs) on quartz substrates. The synthesized SWNTs were comprehensively characterized at the single nanotube level. Owing t...We reported the growth of horizontally aligned nitrogen-doped single-walled carbon nanotubes (SWNTs) on quartz substrates. The synthesized SWNTs were comprehensively characterized at the single nanotube level. Owing to the highly aligned nature of the nanotubes, we were able to investigate the diameter dependent doping mechanism through systematic resonant Raman spectroscopy studies. Other than the formerly found narrowing effect by N-doping, we proposed that the nanotube diameter affects the introduction of N atoms into the carbon lattice in an elaborate way. The obtained doping level increased along with the nanotube diameter but lost the increasing trend when the diameter became larger and experienced a slight decrease after reaching the local peak value. These insights about the heteroatom doping into the carbon nanotubes could benefit the development of the carbon nanotube based functional materials and extend their application in a broad range of areas.展开更多
基金supportted by the Natural Science Foundations of China(No.21203025,No.11004032 and No.11074039)
文摘Nano-crystalline FeOOH particles （5-10 nm） have been uniformly mixed with electric matrix of single-walled carbon nanotubes （SWNTs） for forming FeOOH/SWNT composite via a facile ultrasonication method. Directly using the FeOOH/SWNT composite （containing 15 wt% SWNTs） as anode material for lithium battery enhances kinetics of the Li＋ insertion/extraction processes, thereby effectively improving re- versible capacity and cycle performance, which delivers a high reversible capacity of 758 mAh.g-1 under a current density of 400 mA.g-1 even after 180 cycles, being comparable with previous reports in terms of electrochemical performance for FeOOH anode. The good electrochemical performance should be ascribed to the small particle size and nano-crystalline of FeOOH, as well as the good electronic conductivity of SWNT matrix.
文摘Single-wall carbon nanotubes （SWNTs） with high surface area were synthesized over nanoporous Co-Mo/MgO by a chemical vapor deposition （CVD） method. The SWNTs were used as catalyst support for selective hydrogenation of syngas to hydrocarbons. Here an extensive study of Fischer-Tropsch synthesis （FTS） on CNT-supported cobalt catalysts with different amounts of cobalt loading up to 40 wt% is reported. The catalysts were characterized by different methods including N2 adsorption-desorption, X-ray diffraction, hydrogen chemisorption, inductively coupled plasma （ICP） and temperature-programmed reduction. Enhancement of the reducibility of Co3O4 to CoO, CoO to Co° and small cobalt oxide particles, dispersion of the cobalt, and activity and selectivity of FTS were investigated and compared with a conventional support. The CNT supported catalysts achieve a high dispersion and high loading of the active metal, cobalt in particular, so that the bulk formation of cobalt metal, which tends to occur in conventional support, can be avoided. The results showed that the specific activity of CNT supported catalysts increase significantly （there is a two fold increase in CO Conversion per gram of the active metal） with respect to the conventional supported catalyst.
基金Supported by the National Natural Science Foundation of China (No. 20673019)
文摘We report a theoretical study on the electronic structures of O2 chemisorbed on a（8,0） SWNT with different oxygen contents of 6.25,12.5 and 25%,respectively.On the basis of DFT calculations,we find that eight O2 molecules chemisorbed on the（8,0） SWNT aligned in the middle row of the circumference of the tube in proportional spacing way,is seen to become metallic,and a significant increase in conductivity is expected.There are different electronic structures of the functionalized systems related to different oxygen contents or O2 molecules＇ chemisorbed positions.
基金supported by the Natural Science Foundations of China(No.21203025,51202031,11004032 and 11074039)Funds of Education Committee of Fujian Province(JK2013010 and JA13064)
文摘Conducting supporters of purified single-walled carbon nanotubes（SWNTs） and graphene oxide（GO）were used to confine pomegranate-structured Sn O2 nanospheres for forming SnO-GO-SWNT composites.As anode material for lithium ion batteries（LIBs）, this composite exhibits a stable and large reversible capacity together with an excellent rate capability. In addition, an analysis of the AC impedance spectroscopy has been used to confirm the enhanced mechanism for LIB performance. The improved electrochemical performance should be ascribed greatly to the reinforced synergistic effects between GO and SWNT networks, and their enhanced contribution of the conductivity. These results indicate that this composite has potential for utilization in high-rate and durable LIBs.
基金This work was supported by the Special Fund for Major Basic Research Projects (G2000026403)the National Natural Science Foundation of China (Grant Nos. 50032020 and 50025204)Yang Quanhong is also indebted to China Postdoctoral Science Foundation
文摘This paper reveals, by analyses of nitrogen cryo-adsorption isotherm, the energetic and structural heterogeneity of single-walled carbon nanotubes (SWNTs) which has a high hydrogen storage capacity. It was found that SWNTs had manifold pore structures and distributed surface energy. By comparison of the pore structures and energy distributions of SWNTs before and after hydrogen adsorption, it is preliminarily indicated that hydrogen adsorption occurred in micropores and mesopores with smaller diameter, and that the pores of different diameters determined different hydrogen adsorption processes and underwent different structure changes during hydrogen adsorption.
基金Supported by the National Natural Science Foundation of China (Grant No. 60577049)Shanghai Municipal Science and Technology Commission (Grant Nos. 034319224 and 0652nm017)
文摘Helical amylose/SWNTs complexes (A/S-C) of various sizes, a single nanotube wrapped by amylose in particular, were demonstrated. The formation process of the helical A/S-C was further explained by a novel hierarchical self-assembly model, including the wrapping of amylose chains around SWNT and the hierarchical self-assembly of wrapped-SWNTs into the superstructural A/S-C. Besides the hydrophobic interaction, the hydrogen bonding also plays a certain role in the self-assembly process.
基金supported by the National Science Fund for Distinguished Young Scholars (21425521)the National Natural Science Foundation of China (21521001)+1 种基金the National Key Research and Development Program of China (2016YFA0201300)the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘One dimensional(1 D) nanostructures have many possible applications in electronic, optical, and sensing devices associated with their nanosized lateral dimensions. In this regard, a general and bottom-up strategy to synthesize 1 D nanoparticle arrays and conductive nanowires with a facile structural/compositional control is highly desired. We herein report a protein-sheathed single walled carbon nanotube(SWNT) that satisfies the criteria for an ideal template to assemble micron-long gold nanoparticle(Au NP) linear arrays with high structural rigidity. The resulting Au NP array has minimized inter-particle gaps, which is especially useful to template the overgrowth of Ag, Pd, and Pd/Ag metals into continuous nanowires(Au@M, M=Ag, Pd, Ag/Pd). Our method successfully overcomes the incompatibility between carbon and metal materials, and the resulting superstructured metal nanowires have a tunable diameter below 100 nm and a shape closely replicating a SWNT. The Ag nanowires are composed of coalesced Au@Ag coreshell nanoparticles, while the Pd and Pd/Ag nanowires are made of very fine Pd nanocrystallites around the Au NP cores. These unique structural features are pivotal to various applications including surface enhanced Raman scattering(SERS), electrocatalysis, and gas sensors.
基金supported by the National Natural Science Foundation of China (Nos.51802161, 51772157, and 61504062)Natural Science Foundation of Jiangsu Province (No.BK20160886)+5 种基金Priority Academic Program Development of Jiangsu Higher Education Institutions (No.YX03001)Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Synergistic Innovation Center for Organic Electronics and Information Displays, Jiangsu Province "Six Talent Peak"(No.2014-XCL-014)Qing Lan Project of Jiangsu Province, Jiangsu Higher Education Institutions NSF (No.17KJB430026)Scientific Research Foundation of NUPT (No.NY217012)Graduate Education Innovation Project in Jiangsu Province (No.CXZZ12_0461)Keypoint Research and Invention Program of Jiangsu Province (No.BE2018010-3).
文摘We reported the growth of horizontally aligned nitrogen-doped single-walled carbon nanotubes (SWNTs) on quartz substrates. The synthesized SWNTs were comprehensively characterized at the single nanotube level. Owing to the highly aligned nature of the nanotubes, we were able to investigate the diameter dependent doping mechanism through systematic resonant Raman spectroscopy studies. Other than the formerly found narrowing effect by N-doping, we proposed that the nanotube diameter affects the introduction of N atoms into the carbon lattice in an elaborate way. The obtained doping level increased along with the nanotube diameter but lost the increasing trend when the diameter became larger and experienced a slight decrease after reaching the local peak value. These insights about the heteroatom doping into the carbon nanotubes could benefit the development of the carbon nanotube based functional materials and extend their application in a broad range of areas.
