Synthesis Of Micro-nano Materials With Specific Morphology Through Microwave Heating

As the interdisciplinary of material science and nanotechnology, nanomaterials are also the most basic and active area of nanotechnology and have intense influence on the development of economy and society. In general, nanomaterials is at least one dimension in nanometer-scale range or by the scale as the basic structural unit composed of ultra-fine grain materials. As the particle size approaches nanometer scale, their peculiar physical and chemical properties become quite different with broad application potentials and have great potential applications in many fields.The fabrication of nanomaterials goes deeper with the understanding of their unique properties and the study on nanomaterials' application. Recently, there are many widely used methods to be utilized to synthesize nanomaterials, such as, vapor deposition method, solvothermal reaction, template method, sol-gel method, thermal decomposition method and the ultrasonic method, etc. But these methods have many drawbacks, for instance, environmental pollution, high energy consumption, high cost and rigorous conditions like high temperature and high pressure or usage of expensive equipment. To overcome these shortcomings, we employ environmentally friendly microwave chemistry to synthesis a series of micro-nano materials.Firstly, CdS nanoparticles with average particle size of 50 nm was prepared with microwave method. XRD results indicate that the products are hexagonal crystal structure. The concentration of surfactants and reacting temperature all play important roles in the final morphologies of CdS nanoparticle. The reacting process was studied and mechanism governing the growth of CdS nanoparticle was discussed.Secondly, typical spinning top shape ZnO with average particle size of 1.0μm was prepared with microwave method. XRD results indicate that the products are hexagonal crystal structure. The concentration of surfactants, reacting temperature and blending of magneton all play important roles in the final morphologies of ZnO micro-nano structure. The reacting process was studied and mechanism governing the growth of micro-nano structure was discussed.Thirdly, unusual flower-like ZnO micro-structure was prepared with microwave method. XRD results indicate that the products are hexagonal crystal structure. The concentration of reactants (TEA and ammonia) and reacting temperature all play important roles in the final morphologies of ZnO micro-nano structure. The reacting process was studied and mechanism governing the growth of micro-nano structure was discussed.Finally, super thin Te nanowire was fast prepared with microwave method in 5 min. XRD results indicate that the products are hexagonal crystal structure. HRTEM and FESEM show that Te nanowire is about 5 nm in diameter. Then we use Te nanowire as sacrificial template to fabricate CdTe, PbTe and Au nanowire. The reacting process was studied and mechanism governing the growth of nanowire was discussed.In summary, a systematic investigation has been conducted on the microwave chemistry assisted preparation of micro-nano materials. And we synthesized a series of uniform and good crystallinity of micro-nano crystal.