A new and facile method has been developed for the fabrication of low noise carbon fiber nanoelectrodes. The carbon fiber was flame fused sealed in a tip of the glass capillary. The carbon fiber microelectrodes were m...A new and facile method has been developed for the fabrication of low noise carbon fiber nanoelectrodes. The carbon fiber was flame fused sealed in a tip of the glass capillary. The carbon fiber microelectrodes were made by cutting the protruding carbon fiber to a desired length, and the carbon fiber nanoelectrodes were achieved by etching the protruding carbon on the flame to form a nanometer scale tip. The tip of carbon fiber nanoelectrodes can be controlled within the range from 100 to 300 nm. Thus no epoxy wax was involved in the carbon fiber sealed in glass capillary procedure. The carbon fiber nanoelectrodes were inspected by scanning electron microscopy. The results demonstrated that the surface of the electrodes and the glass/fiber interface are very smooth. Thus the noise caused by the glass/fiber is much lower than that caused by fabricates conventionally. The electrodes were characterized by CV and FSCV measurements of the ferricyanide and 5 Hydroxytryptamine(5 HT) neurotransmitters. The results show that the carbon fiber nanoelectrodes have a very excellent electrochemical behaviors and high sensitivity. This experiments offers a new and facile method for the fabrication of carbon fiber nanoelectrodes with very high sensitivity and low noise.展开更多
DNA immobilization on electrode surfaces has been widely used for fabricating sensors since DNA can interact with a wide variety of biomolecules. Recendy, DNA has been demonstrated as an electronic super conductor... DNA immobilization on electrode surfaces has been widely used for fabricating sensors since DNA can interact with a wide variety of biomolecules. Recendy, DNA has been demonstrated as an electronic super conductor and become the most promising biomolecule for application of chemical sensing in biological system. Calf thymus DNA (ct-DNA) is a most popularly used native DNA in many applications. An electrochemical deposition on carbon fiber micro electrode can provide sensitive detection of dopamine in presence of large amount of ascorbic acid.……展开更多
Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtain...Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtained by using microelectrodes. When the nanoelectrode was in a distance 1 μm above the PC12 cell, only one peak signal corresponding to a single vesicle exocytotic event was detected caused from the stimulation with 1 mmol/L nicotine. The spatial difference of exocytosis was also detected by placing the electrode onto the different locations of the cell body, the results have demostrated that the spatial distribution of dopamine in cells is not uniform and the time for stimulating secretion is very different. Nanoelectrodes electrochemical method can provide a powerful tool for observing the temporal and spatial characteristics of the secretion from single cells directly.展开更多
The inherently low electrical conductivity of TiO2-based electrodes as well as the high electrical resistance between an electrode and a current collector represents a major obstacle to their use as an anode for lithi...The inherently low electrical conductivity of TiO2-based electrodes as well as the high electrical resistance between an electrode and a current collector represents a major obstacle to their use as an anode for lithium ion batteries. In this study, we report on high-density TiO2 nanotubes （NTs） branched onto a carbon nanofiber （CNF） ＂tree＂ that provide a low resistance current path between the current collector and the TiO2 NTs. Compared to a TiO2 NT array grown directly on the current collector, the branched TiO2 NTs tree, coupled with the CNF electrode, exhibited -10 times higher areal energy density and excellent rate capability （discharge capacity of -150 mA.h.g-1 at a current density of 1,000 mA·g-1）. Based on the detailed experimental results and associated theoretical analysis, we demonstrate that the introduction of CNFs with direct electric contact with the current collector enables a significant increase in areal capacity （mA·h·cm-2） as well as excellent rate capability.展开更多
Owing to the excellent redox reversibility and structural diversity,polytriphenylamine(PTPAn)has been regarded as one of the promising cathode candidates for sodium-ion batteries.However,it still suffers from the bulk...Owing to the excellent redox reversibility and structural diversity,polytriphenylamine(PTPAn)has been regarded as one of the promising cathode candidates for sodium-ion batteries.However,it still suffers from the bulk aggregation and low operating capacity in practical applications.Assisted by the in-situ polymerization,leaf-like PTPAn nanosheets are uniformly introduced on the surface of carbon nanofibers(CNFs)to form the free-standing CNF@PTPAn composite electrodes.Interestingly,the formation mechanism of the leaf-on-branch structure of CNF@PTPAn composites is systematically explored,confirming that the controlling of oxidation rate and growth degree plays crucial roles in tuning the morphology and active material content of the composite electrodes.Supported by the capacity-cutting analysis,the effective coupling between the active PTPAn and conductive CNFs can provide fast electron/ion-shuttling channels and deepen the electrochemical reaction process.At 50mAg^(-1),the capacity of the optimized CNF@PTPAn composite can reach 105mAh g^(-1),with a stable rate capability of 78mAh g^(-1)even at 400mAg^(-1)after 500 cycles in a half cell.The detailed kinetic analysis confirms that the ion-storage behaviors in the lowvoltage region can be tailored for the improved capacitive contribution and diffusion coefficients.Meanwhile,the flexible CNF-based full cell with CNF@PTPAn as the cathode and CNFs as the anode exhibits a high energy density of 60Wh kg^(-1)at 938Wkg^(-1).Based on this,the rational design is expected to provide more possibilities to obtain advanced freestanding electrode systems.展开更多
文摘A new and facile method has been developed for the fabrication of low noise carbon fiber nanoelectrodes. The carbon fiber was flame fused sealed in a tip of the glass capillary. The carbon fiber microelectrodes were made by cutting the protruding carbon fiber to a desired length, and the carbon fiber nanoelectrodes were achieved by etching the protruding carbon on the flame to form a nanometer scale tip. The tip of carbon fiber nanoelectrodes can be controlled within the range from 100 to 300 nm. Thus no epoxy wax was involved in the carbon fiber sealed in glass capillary procedure. The carbon fiber nanoelectrodes were inspected by scanning electron microscopy. The results demonstrated that the surface of the electrodes and the glass/fiber interface are very smooth. Thus the noise caused by the glass/fiber is much lower than that caused by fabricates conventionally. The electrodes were characterized by CV and FSCV measurements of the ferricyanide and 5 Hydroxytryptamine(5 HT) neurotransmitters. The results show that the carbon fiber nanoelectrodes have a very excellent electrochemical behaviors and high sensitivity. This experiments offers a new and facile method for the fabrication of carbon fiber nanoelectrodes with very high sensitivity and low noise.
文摘 DNA immobilization on electrode surfaces has been widely used for fabricating sensors since DNA can interact with a wide variety of biomolecules. Recendy, DNA has been demonstrated as an electronic super conductor and become the most promising biomolecule for application of chemical sensing in biological system. Calf thymus DNA (ct-DNA) is a most popularly used native DNA in many applications. An electrochemical deposition on carbon fiber micro electrode can provide sensitive detection of dopamine in presence of large amount of ascorbic acid.……
文摘Carbon fiber nanoelectrodes(200-300 nm) were firstly used to amperometricaly monitor the dopamine release from single PC12 cells with temporal resolution and especially more higher spatial resolution than those obtained by using microelectrodes. When the nanoelectrode was in a distance 1 μm above the PC12 cell, only one peak signal corresponding to a single vesicle exocytotic event was detected caused from the stimulation with 1 mmol/L nicotine. The spatial difference of exocytosis was also detected by placing the electrode onto the different locations of the cell body, the results have demostrated that the spatial distribution of dopamine in cells is not uniform and the time for stimulating secretion is very different. Nanoelectrodes electrochemical method can provide a powerful tool for observing the temporal and spatial characteristics of the secretion from single cells directly.
文摘The inherently low electrical conductivity of TiO2-based electrodes as well as the high electrical resistance between an electrode and a current collector represents a major obstacle to their use as an anode for lithium ion batteries. In this study, we report on high-density TiO2 nanotubes （NTs） branched onto a carbon nanofiber （CNF） ＂tree＂ that provide a low resistance current path between the current collector and the TiO2 NTs. Compared to a TiO2 NT array grown directly on the current collector, the branched TiO2 NTs tree, coupled with the CNF electrode, exhibited -10 times higher areal energy density and excellent rate capability （discharge capacity of -150 mA.h.g-1 at a current density of 1,000 mA·g-1）. Based on the detailed experimental results and associated theoretical analysis, we demonstrate that the introduction of CNFs with direct electric contact with the current collector enables a significant increase in areal capacity （mA·h·cm-2） as well as excellent rate capability.
基金financially supported by the National Natural Science Foundation of China(22075042)the Natural Science Foundation of Shanghai(20ZR1401400 and 18ZR1401600)+1 种基金the Shanghai Scientific and Technological Innovation Project(18JC1410600)the Fundamental Research Funds for the Central Universities and DHU Distinguished Young Professor Program(LZB2021002).
文摘Owing to the excellent redox reversibility and structural diversity,polytriphenylamine(PTPAn)has been regarded as one of the promising cathode candidates for sodium-ion batteries.However,it still suffers from the bulk aggregation and low operating capacity in practical applications.Assisted by the in-situ polymerization,leaf-like PTPAn nanosheets are uniformly introduced on the surface of carbon nanofibers(CNFs)to form the free-standing CNF@PTPAn composite electrodes.Interestingly,the formation mechanism of the leaf-on-branch structure of CNF@PTPAn composites is systematically explored,confirming that the controlling of oxidation rate and growth degree plays crucial roles in tuning the morphology and active material content of the composite electrodes.Supported by the capacity-cutting analysis,the effective coupling between the active PTPAn and conductive CNFs can provide fast electron/ion-shuttling channels and deepen the electrochemical reaction process.At 50mAg^(-1),the capacity of the optimized CNF@PTPAn composite can reach 105mAh g^(-1),with a stable rate capability of 78mAh g^(-1)even at 400mAg^(-1)after 500 cycles in a half cell.The detailed kinetic analysis confirms that the ion-storage behaviors in the lowvoltage region can be tailored for the improved capacitive contribution and diffusion coefficients.Meanwhile,the flexible CNF-based full cell with CNF@PTPAn as the cathode and CNFs as the anode exhibits a high energy density of 60Wh kg^(-1)at 938Wkg^(-1).Based on this,the rational design is expected to provide more possibilities to obtain advanced freestanding electrode systems.
