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Synthesis of Nanoparticles by Electrical Arc Discharge in Liquid Media and Characterization

Ashkarran, Ali Akbar | 2009

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 39714 (48)
  4. University: Sharif University of Technology
  5. Department: Institute for Nanoscience and Nanotechnology
  6. Advisor(s): Iraji Zad, Azam; Mahdavi, Mohammad
  7. Abstract:
  8. In this research we focus on synthesis and analysis of metal and metal oxide nanoparticles and their photocatalytic activity. At the beginning a high current DC power supply and a reactor for the electrical arc discharge process designed and implemented. Several nanoparticles such as tungsten oxide, zinc oxide, silver and gold have synthesized by this method in deionized water, deionized water including surfactants and stabilizers and analyzed. Several characterization techniques such as X-ray diffraction (XRD), dynamic light scattering (DLS) X-ray photoelectron spectroscopy (XPS), BET, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis spectroscopy have used to analyze nanoparticles. XRD analysis of metal oxide nanoparticles demonstrates formation of WO3 and ZnO phase and Optical absorption of metal nanoparticles in DI water exhibits formation of silver and gold. Microscopy analyzes of metal and metal oxide nanoparticles show formation of nanometric particles which found to increase by increasing the arc current and also their size distribution broads. DLS measurements show formation of nanoparticles with average size of 30 nm which grow to 39 and 64 nm by increasing the arc current to 35 and 45 A, respectively. This was 100 to 260 nm for ZnO nanoparticles by increasing the current from 5 to 15 A. surface areas of WO3 and ZnO nanoparticles were 26 and 34 m2/g, respectively. A novel method for synthesis of gold nanoparticles without using gold electrodes proposed. Optical absorption of metal nanoparticles in DI water exhibits silver and gold plasmon resonance at 392 and 550 nm which precipitated in water after 3 weeks. The effect of different stabilizers on stability of metal nanoparticles was evaluated and sodium citrate and CTAB with 10 μM and 50 μM concentrations were chosen as optimum concentration, respectively. Photocatalytic activity of metal oxide nanoparticles reveals their high efficiency in photodegradation of organic compounds such as Rhodamine B
  9. Keywords:
  10. Electric Arc Discharge ; Metallic Nanoparticles ; Liquid Media ; Photocatalytic Activity

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