Synthesis and Thermal Characterization of Co-Doped ZnO Nanocomposites Prepared by Sol-Gel Method

Polyparaphenylene/Zn0.925Co0.075O(PPP/Zn0.925Co0.075O) nanocomposites were synthesized by using a sol-gel method and their thermal conductivity properties were measured. The XRD pattern of Zn0.925Co0.075O shows the single phase wurtzite structure. The SEM images show that the lighter-contrast area is PPP and the dark-contrast area is the polycrystalline of Zn0.925Co0.075O. The increase in the band edge is a clear indication for the incorporation of Co inside the ZnO lattice. The observation of three additional absorption peaks provided evidence that the 3d7 high-spin configuration of Co2+ under the tetrahedral crystal field was probably formed by neighboring O2- ions. With the increase of the PPP content, the thermal conductivity of nanocomposite samples is smaller than those of pure Zn0.925Co0.075O. Due to the high density of interfaces and grain boundaries present in the nanocomposites, the scattering of phonon across a broad wavelength spectrum was enhanced. This suppressed the lattice thermal conductivity of the nanocomposites significantly.

Download Full-text

Structural, Textural and Thermal Characterization of Nano-Mg/Al Hydrotalcite before and after Cr (VI) Removal

Materials Science Forum ◽

10.4028/www.scientific.net/msf.755.53 ◽

2013 ◽

Vol 755 ◽

pp. 53-60

Author(s):

Esthela Ramos Ramírez ◽

Norma Leticia Gutiérrez Ortega ◽

Cesar Augusto Contreras Soto ◽

Gustavo Rangel Porras

Keyword(s):

Crystalline Structure ◽

Sol Gel ◽

Textural Properties ◽

Kinetic Studies ◽

Thermal Characterization ◽

Gel Method ◽

Sol Gel Method ◽

Before And After ◽

Short Time

In this work there was studied the structural, textural and effect that has treat thermal on the removal of Cr (VI) of nanoMg/Al hydrotalcite (NHT) synthesized by the sol-gel method with a ratio of Mg/Al=3. These present the characterization of the nanoMg/Al hydrotalcite before and after Cr (VI) removal, as well as the kinetic studies and of balance. In agreement with the results, when the NHT are thermal treated to 350 °C the hydrotalcite crystalline structure remains but the textural properties are improved and structural. The NHT synthesized by the sol-gel method present a good capacity of removal with values of 91 mg of Cr (VI) removed / g of NHT. The above mentioned capacity of removal gets improved after thermal treating the material, reaching values of removal of 124 mg of Cr (VI) removed / g of NHT. The NHT with the Cr (VI) absorbed show decrease of the crystalline structure, as well as a saturation of the pores that annuls the porosity due to the fact that the Cr (VI) lodges both at the pores and at the intersheets. The time that him takes the HLM to remove the Cr (VI) of the watery solution is alone of 2 minutes, with which it is possible to conclude that the NHT have an excellent aptitude to remove Cr (VI) of watery solutions in an interval of very short time.

Download Full-text

Growth and Characterization of CuO Nanostructures on Si for the Fabrication of CuO/p-Si Schottky Diodes

The Scientific World JOURNAL ◽

10.1155/2013/126982 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 6

Author(s):

S. Çetinkaya ◽

H. A. Çetinkara ◽

F. Bayansal ◽

S. Kahraman

Keyword(s):

Schottky Diodes ◽

Sol Gel ◽

Sem Images ◽

Gel Method ◽

Sol Gel Method ◽

Current Voltage ◽

Current Voltage Characteristics ◽

Cbd Method ◽

Xrd Techniques

CuO interlayers in the CuO/p-Si Schottky diodes were fabricated by using CBD and sol-gel methods. Deposited CuO layers were characterized by SEM and XRD techniques. From the SEM images, it was seen that the film grown by CBD method is denser than the film grown by sol-gel method. This result is compatible with XRD results which show that the crystallization in CBD method is higher than it is in sol-gel method. For the electrical investigations, current-voltage characteristics of the diodes have been studied at room temperature. ConventionalI-Vand Norde’s methods were used in order to determine the ideality factor, barrier height, and series resistance values. It was seen that the morphological and structural analysis are compatible with the results of electrical investigations.

Download Full-text