-
[show abstract]
[hide abstract]
ABSTRACT: Polyaniline-intercalated layered vanadium oxide nanocomposites were successfully synthesized by an one-pot hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR), and Raman spectroscopy. The effects of reaction conditions, such as pH value of the precursor solution, reaction temperature and time, and the amount of aniline on the structure and morphology of the obtained samples, were systematically investigated. Based on the experimental results, an in situ intercalation-polymerization-exfoliation mechanism was put forward for the formation of layered nanocomposites. The application of the resulting layered nanocomposite as the cathode material in lithium battery was tested and the results showed that the polyaniline-intercalated layered vanadium oxide nanocomposite prepared at 140 °C had a good cycling performance and might act as a promising cathode material for high-energy-density rechargeable lithium batteries.
Nanoscale 10/2010; 2(10):2131-8. · 5.91 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Ag2V4O11 nanobelt has been synthesized through a hydrothermal process and its surface segregation leading to the in-situ controllable synthesis of Ag nanoparticles under different irradiation conditions is investigated. The resulted materials are characterized by XRD, TEM, HRTEM, and SAED measurements. It is found that well-distributed Ag nanoparticles with a controlled average diameter in the range of 2-50 nm can be formed in-situ and self-loaded on the surface of Ag2V4O11 nanobelt. The segregation mechanism is also discussed in detail. The silver vanadium salt with self-loaded Ag nanoparticles may find application in catalysis and lithium batteries.
Journal of Nanoscience and Nanotechnology 11/2009; 9(11):6554-9. · 1.56 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Polyaniline (PANI)/Au composite hollow spheres were successfully synthesized using polystyrene/sulfonated polystyrene core/shell gel particle templates. The PANI shell thickness and the number of Au nanoparticles decorating the PANI could be controlled effectively by adjusting the experimental conditions. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres. Furthermore, PANI/Au composites were immobilized on the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI/Au-modified GCEs showed one pair of redox peaks and high catalytic activity for the oxidation of dopamine. The possible formation mechanism of the PANI/Au composite hollow spheres was also discussed.
Langmuir 05/2006; 22(9):4384-9. · 4.19 Impact Factor
-
Macromolecular Rapid Communications 12/2005; 27(1):31 - 36. · 4.60 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A novel and economical microwave route has been developed for the synthesis of electrochemically active LiV(3)O(8) material by using a domestic microwave oven. The heating behavior of the designed reaction system guided the preparation of LiV(3)O(8) at a suitable irradiation power (i.e. heating rate), reaction time, and temperature. At the lowest irradiation power, the conversion fraction of reactants was mainly controlled by reaction temperature. Characterization results of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy, and BET surface areas indicated that the phases of samples prepared by microwave and traditional methods were in good agreement. Nevertheless, the crystallinity, crystallite configuration, and morphology of the samples were different, and were affected by the irradiation time and power. A floppy superposition structure of nanosheets (the size of one nanosheet was about 4.5 microm x 1.2 microm x 3 nm) was preferentially grown at the lowest irradiation power, and this effect on structure was more in evidence as the nanorods formed at the highest irradiation power. Electrochemical studies on ionic conductivity, electrochemical impedance spectroscopy (EIS), and charge-discharge capacity were carried out. It was found that the conductivity, first discharge capacity, and cycle performances of the samples were affected by the crystal size, crystallinity, and crystal configuration and defection concentration. The sample L30 prepared at the lowest irradiation power and the shortest time (30 min) showed the highest discharge capacity (335 mAh/g), but its discharge capacity decreased rapidly. By comparison, the sample L100 had a floppy superposition structure of nanosheets and a high surface area, provided a good two-dimensional channel for the transition of Li(+) ions, and was stable during the intercalation/deintercalation process of Li(+) ions, therefore the high ionic conductivity, high discharge capacity, and good cycle performance were presented. The relationship between the electrochemical properties and the irradiation power was discussed.
The Journal of Physical Chemistry B 07/2005; 109(22):11186-96. · 3.70 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A simple microwave solid-state reactor was designed on the basis of a domestic microwave oven by using graphite powder as heating medium. The heating behavior of the reactor was studied by using an on-line computer to monitor the real-time temperature during irradiation. It was found that the temperature (T) was related to the time (t) and that microwave power depended on the duty cycle (x) of microwave irradiation. Two empirical equations were proposed and could be applied to the similar microwave solid-state reactors. Four inorganic layered materials, LiV(3)O(8), KNb(3)O(8), KTiNbO(5), and KSr(2)Nb(3)O(10), were successfully synthesized in the designed reactor at a suitable heating rate and temperature that were fully controlled by the empirical equations. Characterization results of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, and scanning (SEM) and transmission (TEM) electron microscopy indicated that the phases of samples prepared by traditional and microwave methods were in good agreement; nevertheless, the heating nature and the morphologies of products were quite different. The samples synthesized in the microwave field had crystallographic defects and showed an incompactly stacking structure of nanosheets. Due to the rapid formation of crystallites and different extended growth rate along the crystal axis of the products in microwave field, the crystal growth mechanism of layered metal oxides was not according to that of the traditional method and is briefly discussed.
The Journal of Physical Chemistry B 03/2005; 109(4):1371-9. · 3.70 Impact Factor
