| As one of the most important research points, nanomaterials have been applied in varies aspects, improved human's life. Due to their characteristic of small size, nanomaterials possess many excellent properties compare with traditional materials (e. g. surface effect and quantum size effect), which makes them be used more widely as functional materials. Some of the properties of nanomaterials, for example, catalyzing property, are associated with the size and surface area of the materials. Small size and big ratio large aspect and surface-to-volume ratio are found to be important factors that affect the efficient parameters, especially when the size of the material is reduced to nanoscale. For nanobelts and nanoplates, the single crystalline nature and, in particular, their large aspect ratio as well as the faceting nature make them ideal candidates for probing size- and dimensionality-dependent physical or chemical phenomena as well as for applications in nanodevices.MoO3 and MoO2 are two of the most important in molybdenum oxides. MoO3 prefer to form layered morphology because of its unique layered structure. While MoO2 materials with nanosize, especially plates-like morphology are rarely found. Synthesizing and studying MoO3 and MoO2 nanostructures will help to wider application of molybdenum-based materials. Highpressure study of nanomaterials is an important aspect when study materials physical behavior under extreme conditions. By comparing the phase transition of nanomaterial and correspondent traditional materials, and exploring the possible new properties and application, it is easy for people to make more wide usage of nanomaterials.In this thesis, we synthesized hexagonal and truncated hexagonal shaped MoO3 nanoplates (MoO3 HNP) and MoO2 rhombus microplates through a simple vapor-deposition method in Ar atmosphere under ambient pressure without the assistant of any catalysts; MoO3 HNP were characterized by varies methods, and photoluminescence (PL) were taken. Possible growth mechanism were reported; structure of MoO2 rhombus microplates are given by XRD test and the shape is shown by SEM test; synchrotron radiation X-ray diffraction was taken on MoO2 rhombus microplates using ultra-highpressure instrument(DAC), highpressure data of MoO2 under ambient pressure was given for the first time, possible phase transitions are found.The structure and morphology of MoO3 HNP were investigated by XRD, EDX, SEM, TEM, and HRTEM. The results reveal that the HNP areα-MoO3 and have a large area surface. The Raman spectrum shows a significant size effect on the vibrational property of MoO3 HNP. The photoluminescence (PL) spectrum was carried out, and two peaks at 351 and 410 nm were observed in the spectrum. In addition, a possible growth mechanism proposed as VS is discussed in detail.The XRD data suggests that the MoO2 rhombus microplates are monocline with high crystallinity. The SEM pictures showed that the rhombus microplates are regular in shape with smooth surface and straight edge. Generally, MoO2 materials prefer to form nanosticks or nanoparticles, plates like structures are firstly found in synthesis of MoO2 nanomaters. It is possible to reduce the size of the microplates to nanosize by controlling the reaction conditions (e. g. temperature or reaction time). These microplates possess high surface area, which points to important application meaning in optical devices and catalysts.Synchrotron radiation X-ray diffraction was taken on MoO2 rhombus microplates. Highpressure X-ray data of MoO2 is tested for the first time. The pressure is from 0.63GPa to 39GPa. Two possible phase transitions are found at 10.88GPa and 28.6GPa, respectively. |
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