| Nanomaterial and nanotechnology have existed for about 30 years and they have important and deep influences on material science, bioscience, military technology, electronic technology, micro device fabrication and human daily lives in this century. Nanomaterials are the base of the whole nanoscience and nanotechnology and many synthesis methods have been exploited and developed to effectively control the formation of nanomaterials. The ultimate purpose is to manipulate the physical and chemical properties of nanomaterials to make them competent for different practical applications and perform best.Nano SnO2 is an n-type semiconductor with a wide band gap and can be used in catalysis, sensing and electrodes of lithium-ion batteries etc. Now, the research on nano SnO2 mainly includes the control over morphology, doping and coating, assembly of building units and their applications. People can fabricate SnO2 nanomaterials and adjust their properties at human own will and realize the use values of SnO2 if only people can perfectly master all the fabrication methods.The subject clue of this thesis is the synthsis of SnO2. Some methods of the fabrication of nano SnO2 are studied and further applied to fabricate other inorganic nanomaterials. So the thesis contains 3 major parts on the basis of different methods.The first part includes chapter 2,3 and is about the Interface Reaction-Hydrothermal Crystallization of metal-oleate. Chapter 2 is about the synthesis of nanocrystalline SnO2 via the Interface Reaction-Hydrothermal Crystallization of Tin-oleate and its properties and applications. The employed solvents affect the quality of final products. When the mixed solvent composed of water and ethanol is used, the final powder has better dispersity and higher BET surface. When pure water is used, SnO2 nanoparticles tend to agglomerate closer and adhere to each other and have lower BET surface. What's more, the SnO2 synthesized in pure water is brown, which is due to the mild carbonization of adsorbed oleic acid. The difference of the surface condition between the two products affects the optical band gap. Additionally, the synthesed SnO2 is used in lithium-ion batteries and shows good performance. Chapter 3 is about the application of the Interface Reaction-Hydrothermal Crystallization to synthesis of NiFe2O4 and CoFe2O4 magnetic nanomaterials and the microwave absorbing application. Taking NiFe2O4 for example, the influences of temperature, time, solvents and alkali are systematically studied. It is showed that only if the temperature is not lower than certain degrees, metal-oleate complex can react with alkali and be changed into corresponding ferrite. Viscosity, dielectric constant, alkali and time affect the final products. Due to the high crystallization, good dispersity and high saturation magnetization, the synthesed nano NiFe2O4 shows good microwave absorbing properties.The second part includes chapter 4,5 and is about the high temperature carbonization of metal-oleate under the nitrogen atmosphere. Chapter 4 describes the synthesis of SnO2&C nano composite by high temperature carbonization of water-rich Tin-oleate under the nitrogen atmosphere. By the hydrolysis of Tin-oleate at low temperature and the carbonization of oleic acid at high temperature, the black SnO2&C nano composite can be gotton. Due to the protection of carbon, the size of SnO2 nanoparticles is small and uniform. But, the reduction happens during the carbonization process, which can be suppressed to decrease the amount of the reduced Sn by lowing down the carbonization temperature. The fabricated SnO2&C nano composite with high surface area shows good performance in lithium-ion batteries application. Chapter 5 is about the application of high temperature carbonization of metal-oleate under the nitrogen atmosphere to synthesis of magnetic Co&C and Ni&C nano composite. By comparing with the high temperature carbonization of Mn-oleate, the formation mechanism is discussed. The diversity of thermolysis temperature and the catalyzed carbonization determine the chemical valence of the final products.The third part includes chapter 6,7. Chapter 6 introduces the hydrothermal synthesis of 3D SnO2 nanoflowers and its optical properties. Na2SnS3, as a new Tin source, is used here, and the mechanism is fully discussed. The controlled release of Sn(OH)62-is important to the oriented growth along the favored growth direction (c-axis). During the whole process, the controlled release of Sn(OH)62- is achieved via the gradual hydrolysis of SnS32-, and the low concentration of Sn(OH)62- keeps. The low concentration of Sn(OH)62- ensures the growth along the favored growth direction at a relatively low speed. The synthesized 3D SnO2 nanoflowers show different photoluminescence properties under various excitation wavelengths. As the extending of chapter 6, chapter 7 is about the synthesis of nano SnS2 by using acid precipitation method that has been mentioned in chapter 6. The influences of acids and solvents are studied. When HCl is used, due to the coordination dissolution of SnS2, there exist a lot amount of SnO2. While acetic acid or oleic acid is used, sheet-like or flower-like SnS2 can be gotton. What's more, the solvents affect the stacking of SnS2 sandwich layers and induce different structures. |
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