Design, Preparation And Properties Of CuO And ZnO Nanomaterials

Metal oxide nanomaterials combine an infinite variety of structural geometriesand morphological features, which can exhibit metallic, semiconductor, or insulatorcharacteristics, as well as unique chemicophysics and quantum properties ofnanomaterials. The broad application prospect of metal oxide nanomaterials inchemistry, physics and material science makes them an indispensable part fornanotechnological innovations. In this work, CuO and ZnO are chosen asinvestigative subjects. Various morphologies and structures of metal oxides (CuO,ZnO) nanomaterials have been successfully designed and prepared using typicalliquid-phase methods. The properties of the as-obtained CuO nanomaterials havebeen investigated as anode materials of lithium ion batteries and the as-preparednanostructured ZnO samples have been used as photocatalysts for photodegradationof RhB aqueous solution. The relationships between morphologies, structures andproperties have also been studied. The main points are summarized as follows:1. A green synthetic pathway for CuO hollow nanostructures is proposed inthis thesis. The Cu2O nanospheres as precursor are prepared by precipitationmethod at room temperature. Followed by a simple thermal oxidation strategy, CuOhollow nanospheres are successfully synthesized due to Kirkendall effect. As anodematerials for lithium ion batteries, the as-prepared CuO hollow nanospheresassembled by nanoparticles exhibit higher discharge capacity and better cycleperformance compared with the single-structured CuO nanoparticles.2. Microemulsion combined with direct growth on Cu substrate can achievethe controllable synthesis of CuO nanostructured films. InCTAB/n-hexanol/n-hexane system, rod bundle-like Cu(OH)2nanostructured filmsare firstly synthesized on Cu foils at room temperature. Subsequently, CuOnanostructured films are obtained by thermal treatment of the Cu(OH)2precursor.The as-prepared CuO nanostructured films on Cu substrate as anode materials oflithium ion batteries exhibit excellent electrochemical lithiation performance. Theeffect of film density on the electrochemical performance of the CuO electrodes hasbeen discussed. It is confirmed that adequate increase of film density can improvethe reversible capacity and rate capability.3. ZnO micro/nanomaterials with different morphologies and structures can be obtained by adjusting hydrothermal reaction conditions. During the hydrothermalprocess, ZnO with different morphologies such as microspheres and microflowerscan be controllable obtained by simply varying the amount of diethylamine. ZnOmicrospheres and microflowers are assembled by nanoparticles and nanoplates,respectively. The morphology dependent photocatalytic results show both ZnOproducts exhibit good photocatalytic activities, while ZnO microflowers cancompletely degrade RhB solution in a short time because of their highconcentration of native defects.4. Microemulsion combined with direct growth on Zn substrate can achievethe controllable synthesis of ZnO nanostructured films. In NaAOT/isooctanesystem, flower-like ZnO nanostructured films are synthesized on Zn foils underhydrothermal condition. The photocatalysis results show that the RhB solution canbe completely degraded in3h using ZnO nanostructured film as photocatalyst.Meanwhile, it keeps excellent catalytic activity up to5cycles, which shows theZnO nanostructured film is stable and feasible to be used as an efficient andrecyclable photocatalyst material.