Synthesis Of Metal Oxides Nanostructures With Zeolites And High-silica MOR Type Zeolite With Ether

This thesis includes two parts: No 1: Synthesis of metal oxides nanostructures with various morphologies with zeolites as scaffold. No 2: Synthesis of high-silica MOR type zeolite with ether as the template.Semiconducting oxides are the basis of smart and functional materials, which are broadly used as a very important material for application of gas sensors, transistors, electrode, catalysis and solar cells. It is well known that small particles with the size in nanometer region exhibit physical and chemical properties that differ markedly from those of the bulk material, such as quantum confinement, effect of small size and effect of surface. The enormous surface area-to mass ratio of metal oxide nanoparticles leads their chemical and physical properties in difference with those of the bulk material with the same chemical composition. Nanoparticles of metal oxides are usually used as a important material in the fields of chemistry, biology, physics, materials and medicine.The phenomenon of inter-surface between metal oxides with high melting point and zeolites has been explained by thermodynamics and physical Chemistry of Surface. We believe that there isn't monolayer spreading of the metal oxides on zeolites, and suppose that there is de-wetting effect for the metal oxides on zeolites. In the light of the idea, we design some experiments by using FAU (NaY) type zeolite with various silicon-aluminum-ratio, and MFI, FER, STI type zeolite, which possess two MR channels, and TON, LTL type zeolite with one MR channels as scaffolds, and tin dioxide (SnO₂) as the metal oxide with high melting point.Nanorods, nanocones, and nanoparticles of SnO₂ on NaY zeolite with low silicon-aluminum-ratio were prepared. The morphology of the oxid nano-crystallites formed on NaY zeolite depends intensively on the calcination temperature in the preparing process. Nanoparticles of SnO₂ form at 350℃. Cone like nano-crystallites form at the temperature < 500℃ such as at 400℃. The SnO₂ nanorods crystallize at 500℃ or at 600℃. The size of the perfect uniform and single nanorod with smooth crystal faces is about 12×60 nm and with the aspect ratio of 5. An isotropic spherical growth occurs at 700℃. The growth of SnO₂ nanorods on the zeolite is dominated by a self-catalytic vapor-liquid-solid mechanism.In the same condition of preparation, SnO₂ nanorods on NaY zeolite can't be prepared byusing NaY zeolite with higher silica/alumina ratio as the scaffold. This is because of the increase of spreading effects between SnO₂ and NaY zeolite. The square form of SnO₂ nanoparticles with size of 15 nm were found to form on NaY zeolite. On the other hand, the SnO₂ nanoparticles of 5nm form on NaY with higher silica/alumina ratio since increasing the spreading effects between SnO₂ and NaY zeolite.Salts present lower free surface energy than that of high melting point metal oxides, and are easier to form monolayer on zeolites. It is favorable to reduce the free surface energy of zeolites for growing SnO₂ nanorods. NaCl was added as a salt to the synthesis system for growing SnO₂ nanorods on zeolite. Therefore, SnO₂ single nanorods with the size of about 100 X 10 nm and the aspect ratio of 10, form on the outer surface of NaY zeolite. The nonorods are perfect and uniform single crystallites with smooth crystal faces, which were obtained by decomposition of SnO₂-NaY in 40% hydrofluoric acid at room temperature.The property of surface bonds of FAU type zeolite would be modified by ion exchange. Increasing the spreading effects of SnO₂ on the zeolite would be possible by using an FAU zeolite which was exchanged with alkaline-earth metal ion for replacing Na+ in NaY. Square form nano-particles of SnO₂ with 10-20nm in size were found to grow on the outer surface of MgY zeolite. The SnO₂ nano-particles with 15nm in size form on the surface of CaY zeolite crystallites. Obviously, the replacing Na+ with Cu2+ in NaY intensively changes the property of the surface bonds of the zeolite. As a result, SnO₂ nanoparticles, 10 nm in size, were found to form a compact shell on CuY zeolite. SnO₂ microcapsules, which have a shell composed by SnO₂ nanoparticles and a hollow core in size of micron or submicron, were obtained by decomposition of SnCuY in 40% hydrofluoric acid at room temperature. The microcapsules are a type of nanostructure material and would exhibit novel physical and chemical properties. The nanoparticles of the oxide, 15 nm in size, were also found to form on the outer surface of the crystallites of BEA type zeolite with three MR channels.The nanoparticles of SnO₂ can also grow on the outer surface of the crystallites of MF1, FER, STI type zeolites which possess two MR channel systems in our preparation. But the morphology of the nanoparticle is quite different from those grown on FAU type zeolite because of difference of surface bonds. SnO₂ nanoparticles gather at the crystal angles and edges of MFI type zeolite (ZSM-5). The nets of SnO₂ nanoparticles formed were obtained by decomposition of ZSM-5...