Research On Synthesis Of Nanometer-sized CuO_x(x=0, 0.5, 1) Powders And Their Catalytic Performances On NH₄ClO₄ Decomposition And Photo-degradation Of Methylene Blue

CuO_x(x=0, 0.5, 1) based materials has drawn significant attentions in the applications of the catalysis on NH4ClO4 decomposition, gas sensors and photocatalysts. In past decade, nanostructures of oxides became a focus of attention of researchers because of their unique properties and potential applications in the future nanodevices. It has been well accepted that size and morphology of nanomaterials are crucial issues for their application and great efforts have been devoted to achieve size and morphological controllable syntheses of semiconductor nanocrystals. Therefore, it is of great importance to produce CuO_x based materials with well-controlled dimensionality, sizes and crystal structure for basic research, as well as being relevant for industrial and high-technology applications.In this dissertation, valuable explorations have been carried out on the solution-based routes to CuO_x-based nanomaterials, their optimum preparation conditions as well as their formation mechanism. Based on a wide and in-depth literature investigation, CuO_x-based nano-oxides with different morphologies have been successfully synthesized by wet chemical method (hydrothermal, microwave hydrothermal or ultrasonic route). The obtained powders were characterized by XRD and TEM. The catalysis of the different morphologies of nanocrystalline CuO_x powders on AP decomposition and photo-catalytic degradation of methylene blue were investgated,respectively. The details are summarized as follows:1. Rod-shaped, spherical, shuttle-shaped and starfruit-like CuO nanopowders were prepared with a sonochemical process and microwave-hydrothermal technique, respectively. The catalysis of the different morphologies of nanocrystalline CuO powders on NH4ClO4 decomposition was investigated by thermal analysis. The results show that CuO nanocrystals of different morphologies can all catalyze strongly the AP's decomposition. The rod-shaped and spherical CuO nanopowders show better catalytic properties due to their smaller sizes. The spherical CuO lowers the second thermal decomposition temperature of AP by 122℃, and the temperature is lowered by 124.4℃for rod-shaped one. The low exothermic peak of AP decomposition disappears for both of spherical and rod-shaped ones.2. Cu₂O hollow nano-cubic and nano-ball, Cu nano-ring and nano-beam, and nano-CuO/ZnO were obtained by using HMTA as a reducing agent and auxiliary reagents with hydrothermal method. Their catalytic activities on AP was investigated by thermal analysis. The results show that Cu2O hollow nano-cubic and nano-CuO/ZnO can all catalyze strongly the AP's decomposition. The nano-CuO/ZnO shows better catalytic property due to its hybrid structure, and lowers the second thermal decomposition temperature of AP by 170℃.3. Nano-porous Cu₂O and solid cubic structure nano-Cu powders have been synthesized with hydrothermal method, using starch as the reductant. The nano-porous Cu2O shows excellent photocatalytic property by investigating its uv-visible absorption spectra. The degradation rate of methylene blue solution(50 ppm) up to 99.45% under sunlight illumination within 98 min.4. Summary for the contents of this paper was discussed and the prospect of the development of our work based on the current experiments was addressed.