ZnO@Co Hybrid Nanotube Arrays Growth From Electrochemical Deposition: Structural, Optical, Photocatalytic And Magnetic Properties

Hybrid nanostructures which have multifunction and perform several technological tasks simultaneously are at the forefront of current research. The heterodimer structures realize new combination of material properties, and have unique and different physical properties because of the interaction between two or more inorganic components which can modulate properties of one component. Semiconductor-based hybrid nanocrystals inaugurate new applications for biotechnology such as drug delivery, cellular imaging, and microlasers, and potocatalysis in the environmental problems. Semiconductor nanocrystals have more excellent fluorescent semiconductor with high chemical stability than organic dye. Therefore, it is a challenge to develop new methods or strategies to design and synthesize semiconductor-based nanostructures with unique properties. In this thesis, we focus on designing and synthesizing ZnO-based hybrid nanomaterials, and investigate their properties and potential applications.In Chapter I, we first introduced the applications of semiconductor quantum dots, magnetic nanoparticles, and noble metal nanoparticles in both nano-electronics and nanobiology fields briefly. Then we summarized the important features and different synthesis routes of the hybrid nanomaterials such as, metal/semiconductor, magnet/semiconductor, and metal/magnet and so on. Their unique properties and potential applications were discussed.In Chapter II, well-aligned ZnO@Co hybrid nanotube arrays on conductive glass substrates have been fabricated by an electrochemical deposition approach. Vertical-aligned ZnO nanotubes with sizes between 300 and 600 nm in diameter and wall thickness of ~100 nm have been prepared by selective dissolution from the nanorods. The ZnO@Co heterostructures can be prepared by optimizing the deposition time and controlling the stability of Co2+ ions. Compared to the nanorod arrays, both nanotube arrays and the ZnO@Co heterostructures show enhanced photoluminescent properties. In addition, ZnO and ZnO@Co nanotubes show improved photocatalytic property compared with the bare ZnO nanorod array, and the hybrid nanotubes exhibit better adsorptive property than the bare ZnO nanotubes. The ZnO@Co heterostructures show ferromagnetism at room-temperature.In Chapter III, we take a survey for the nowadays development of Fuel Cells, which informs me that the materials of anode in Fuel Cells is the key factor to the performance and development of Fuel Cells. Investigating new materials to substitute the noble metal becomes more and more urgent for nowadays research on Full Cells. We plan to design and fabricate new materials to cater the demand of anode in Fuel Cells, such as the tolerance to the impurities in the fuel, the low capital cost and low operating cost and so on.