lecture-hydrothermalreaction摘要.ppt

* * * TEDDI (Tomographic Energy-Dispersive Diffraction Imaging). * * * * * Hydrothermal synthesis is a common method to synthesize zeolite/molecular sieve crystals. This method exploits the solubility of almost all inorganic substances in water at elevated temperatures and pressures and subsequent crystallization of the dissolved material from the fluid. Water at elevated temperatures plays an essential role in the precursor material transformation because the vapor pressure is much higher and the structure of water at elevated temperatures is different from that at room temperature. The properties of the reactants, including their solubility and reactivity, also change at high temperatures. The changes mentioned above provide more parameters to produce different high-quality nanoparticles and nanotubes, which are not possible at low temperatures. During the synthesis of nanocrystals, parameters such as water pressure, temperature, reaction time, and the respective precursor- product system can be tuned to maintain a high simultaneous nucleation rate and good size distribution. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * TEM images of the samples H-titanate fibers HRTEM image of the fibers The product of the phase conversion reaction at 373K, a titanate fiber covered with anatase crystals The product obtained at 393 K, fibril aggregates of anatase nanocrystals Hydroxyapatite sheet prepared by hydrothermal one-process method Hydroxyapatite (Ca10(PO4)6(OH)2, HA) Excellent biocompatibility Bone-repairing material: directly bond to natural bones in bony defect Using hydrothermal reactions for HA preparation, it is possible to control the crystal face, pore structure, and its chemical composition. Hydrothermal deposition of functional ceramic thin films Crystalline TiO2 films have been synthesised at 60?C and are targeted for use as optical and photocatalytic coatings. AFM micrographs of film