Dissertation > Excellent graduate degree dissertation topics show

Single - source precursor prepared oxides and sulfides nanomaterials

Author: SunJiQuan
Tutor: ShenXiaoPing
School: Jiangsu University
Course: Inorganic Chemistry
Keywords: nanomaterials microwave synthesis solvothermal synthesis single-source precursor oxide sulfide
CLC: TB383.1
Type: Master's thesis
Year: 2009
Downloads: 11
Quote: 0
Read: Download Dissertation

Abstract


Nanomaterials can exhibit unique physical and chemical property arising from their small size effect, quantum size effect, surface effect and macroscopic quantum tunneling effect, and thus they are expected to have many potential applications in electronics, catalysis, sensors, energy storage, solar cells, and nanodevices etc. It is generally accepted that the preparation of nanomaterials is fundamental to the development of nano-science and nano-technology. In recent decade, much attention has been paid to the preparation of nanomaterials with controllable size and shape, and a great progress has been achieved. In this paper, the basic concept, preparation methods, properties and development trends for nanomaterials were first reviewed. Then, a single-source method for nanomaterial preparation was investigated under microwave and solvothermal conditions and a variety of nanomaterials including ZnO, ZnS, PbS, NiS and Sb2-xBixS3 with various shape and size were successfully synthesized and characterized by XRD, SEM, FESEM, TEM, HRTEM and SAED etc. The optical properties of them were also studied.1. Using Zn（acac）2·H2O （acac = acetylacetonate） as a single-source precursor,the flower-, rod-, sheet- and spindle-like ZnO nanostructures have been synthesized via microwave method by adjusting the reaction time, surfactant and solvent. A possible formation mechanism for these ZnO nanostructures was proposed. The UV-Vis absorption spectrum and photoluminescence spectrum of these ZnO nanostructures were investigated.2. Hexagonal phase ZnS nanocrystals with the size of 5 nm were synthesizedby microwave thermolysis of a single-source molecular precursor of zinc diethyldithiocarbamate [Zn（DDTC）2]（DDTC=diethyldithiocarbamate） in ethylene glycol at low temperature. A strong blue emission band centered at about 426 nm was observed in the photoluminescence spectrum, which could be associated with the sulfur vacancy and interstitial sulfur lattice defects.3. PbS crystals with flower-, sheet-, cube-like morphology have been synthesized via microwave method by adjusting the reaction time, surfactant and solvent by microwave thermolysis of a single-source molecular precursor of lead diethyldithiocarbamate （Pb（DDTC）2·5H2O）. The reaction mechanism together with the role of ethylenediamine was discussed. A strong blue-shifted absorption band centered at about 260 nm was observed in the UV-Vis absorption spectrum of the flower-like PbS crystals, which could be attributed to the quantum confinement possibly occurs near the tip of the PbS petals.4. The urchin-like nanostructures of NiS were successfully prepared usingnickel diethyldithiocarbamate （Ni（DDTC）2） as a single-source precursor via a solvothermal treatment in presence of SDS as surfactant. The urchin-like pattern has a diameter of about 15 nm with acicular crystallites radiating from the center core. The average diameters of nanoneedles are about 20 nm. A possible formation mechanism for the NiS nanostructures was proposed. We found that both the solvent and the surfactant played important roles in the formation of urchin-like NiS.5. The flower-like nanostructures of Sb2-xBixS3（x=0.4, 1） were successfullyprepared using a mixed precursor of Sb（DDTC）3 and Bi（DDTC）3 at various ratios via a solvothermal process at 180℃. The flower-like architectures, with an average diameter of 4μm, were composed of single-crystalline nanorods with orthorhombic structures. The optical absorption properties of the Sb2-xBixS3 nanostructures were investigated by UV-Visible spectroscopy, and the results indicate that the Sb2-xBixS3compounds are semiconducting with direct band gaps of 3.0 and 3.2 eV for x=0.4 and 1.0, respectively. On the basis of the experimental results, a possible growth mechanism for the flower-like Sb2-xBixS3 nanostractures is suggested.

Related Dissertations

  1. Technology of Filling Clearance and Optimizing the Bonds during Ultrasonic Brazing,TG454
  2. Phosphogypsum to restore the system vulcanizing process optimization and research of calcium,X786
  3. Under microaerobic conditions closed calcium carbide furnace exhaust COS gas adsorption purification,X781
  4. Design, Synthesis and Antitumor Activities Study of Quinoxaline-1,4-dioxide Derivatives,R914
  5. Of Bi N Co-doped TiO \u003csub\u003e 2 \u003c/ sub\u003e of the preparation and performance,O614.411
  6. Department of Bi-based Co-based oxide thermoelectric ceramics and thin films,TQ174.7
  7. LSGM electrolyte thin films and electrochemical properties of,TM911.4
  8. Synthesis and properties of new functionalized graphene oxide drug carriers,TQ460.4
  9. Preparation, Characterization and Application of Prussian Blue Composite Nanomaterials,TB383.1
  10. Recovery Sulphur from Zinc Concentrate of Pressure Acid Leaching Residue,X751
  11. Studies on the Effects of Exogenous Nitric Oxide on Rice under Cadmium Stress,S511
  12. Study on Heat Resistance of Chrysanthemum Floral Organ and Effects of Exogenously Nitric Oxide on Heat Resistance of Chrysanthemum,S682.11
  13. Tissue-engineered Construction and Preliminary Implantation Study of Diamond-like Carbon Films for Artificial Mechanical Valve Applications,R654.2
  14. The protective effect of the new gaseous signal molecule of non-steroidal anti-inflammatory drug -induced gastric lesions,R96
  15. Kinase Activities Analysis and Localization of ZmCCaMK Induced by Abscisic Acid in Leaves of Maize Plants,S513
  16. Effects of Cold-adaptation Swimming on Hemorheology and Quantity of NO and NOS in Aorta of SD Rats in Acute Cold Water Stress,R87
  17. Preparation and Photocatalytic Properties of Semiconductor Oxides,O643.36
  18. First-Principles Studies of Cathode Material Srn+1TinO3n+1（n=1,2,3,∞） for Solid Oxide Fuel Cell,TM911.4
  19. Changes and Roles of Plasma Hydrogen Sulfide in Elderly Patients with Ischemic Heart Failure,R541.6
  20. The Relationship between Exhale Nitric Oxide and Serum Eosinophil Cationic Protein, IL-13, IL-8 in Acute Asthma Exacerbation,R562.25
  21. The Role and Mechanism of Hippocampus H2S/CBS Systemon Epilepsy Production,R742.1

CLC: > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials
© 2012 www.DissertationTopic.Net  Mobile