Studied The Preparation Of Low-dimensional Metal Oxide Material Microstructure And Physical And Chemical Properties

As an important functional material, low-dimensional metal oxide has good optical, electrical, thermal and mechanical properties. The application of low-dimensional metal oxide has been demonstrated in many areas, such as laser device, catalysis, and sensors. The chemical and physical properties of low-dimensional metal oxides depend greatly on their microstructure. In this thesis, preparation, microstructure, physical and chemical properties of low-dimensional transitional metal oxides are systematically investigated.In chapter1, the preparation, characterization, physical and chemical properties, application fields and prospects of low-dimensional metal oxides are reviewed. In addition, the studies of in-situ electrical properties and photocatalytic performance of nanomaterials are also introduced in details.In chapter2, bicrystalline a-Fe2O3nanoblades were synthesized through oxidation of sandblasted Fe foils. Transmission electron microscopy examination of individual nanoblades demonstrates that all the bicrystalline nanoblades possess coincidence site lattice (CSL) boundaries with only three distinct∑values of9,13, and19. In-situ electrical measurement shows thata-Fe2Ob nanoblade has a lower resistivity compared with a-Fe2O3nanowire,, and the resistivity decreases with the increase of∑value of the CSL boundaries. Magnetic measurement shows that a-Fe2O3nanoblade has a sharp transition from canted ferromagnetic phase to another antiferromagnetically ordered state.In chapter3, polyhedral Cu2O NPs/CuO NWs were produced by thermal reduction of CuO NWs in vacuum. The parent CuO NWs serve as a skeleton and the lower oxide of Cu2O phase resulting from the CuO reduction forms as cubic or octahedral NPs on the parent CuO NWs. The shape selection of the Cu2O nanocrystals is governed by the orientation relationship between Cu2O NPs and CuO NWs. Under the same experimental conditions, the photocatalytic degradation efficiency of CuO NWs is about18%, while the photocatalytic degradation efficiency of Cu2O NPs/CuO NWs is75%.In chapter4, various ZnO nanostructures were synthesized through thermal oxidation of Cuo.7Zno.3alloy (brass) and pure Zn foils. The oxidation temperature below the melting point of Zn results in the growth of bicrystalline ZnO nanowires, while the oxidation temperature between the melting and boiling points of Zn leads to formation of single-crystalline ZnO nanowires. However, ZnO tetrapods will form when the temperature is above the boiling point of Zn. The temperature-dependent growth morphology and microstructure are attributed to the temperature effect on the oxidation mechanism of Zn. For the Cuo.7Zno.3substrate, the density of ZnO nanowires decreases with the increase of the thermal oxidation temperature.