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
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
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
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.
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.
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.
