Synthesis And Electrochemical Properties Of Micro-/Nanostructures Of Metal Oxides

The purpose of this dissertation is to explore the controllable synthesisof inorganic micro-/nanostructures in solution phase by applying a simplecoordination chemistry principle, developing the effective methodologyto control both the phase and morphology of the final products. Moreover,the corresponding properties of the as-obtained inorganic micro-/nanostructures on electrochemical sensors of heavy metal ion of Hg²⁺orlithium ion batteries were also investigated. The details are summarizedbriefly as follows:1. Folding flake-like CuO （FFL CuO） micro-/nanostructure wassuccessfully prepared on a large scale using a facile1,6-hexanediaminassisted low-temperature solution approach. The growth mechanism ofthe sample was discussed based on the time-resolved experiments. Theexperimental results demonstrated that the microstructures of CuOstrongly depended on the concentration of the1,6-hexanediamin. Theas-prepared CuO micro-/nanostructures were dispersed in Chitosan （CH）solution to fabricate composite film on glass carbon electrode （GCE）. Theelectrochemical study has shown that the FFL CuO sub-microstructureexhibits highest catalytic effect on Hg²⁺than other CuO micro-/nanostructures. The amperometric response exhibited that the FFL CuOmicro-/nanostructure modified glassy carbon electrode has a goodresponse for Hg²⁺with a linear range of1μM to200μM in pH6.0phosphate buffered solutions.2. NiO nanosheets with uniformly distributed mesoporosity weresuccessfully synthesized on a large scale by calcination-Ni（OH）2nanosheet precursor, which was simply prepared using1,6-hexanediaminassisted solution approach. The as-prepared mesoporous NiO nanosheetshave been introduced for the first time for the sensing of mercury ionsbased on the construction of the NiO-CH/GCE electrode, which wasfound to be useful for selective electrochemical detection of Hg²⁺with alinear range of0.8μM to500μM in pH6.0phosphate buffered solutions, providing us another opportunity for exploring new electrochemicalapplication of NiO nanomaterials.3. Two different phases of vanadium dioxide, tetragonal phase of VO₂（A）and monoclinic phase of VO₂（B） with one-dimensional （1D）nanostructures of nanosheets and nanorods were successfully synthesizedon a large scale by a simple hydrothermal growth route using the rawmaterial vanadyl acetylacetonate （VO（acac）₂） and water. The possiblemechanisms of the formation of1D nanostructures were elucidated basedon the layered structure of vanadium dioxide and the hydrolysis andcondensation of the material of VO（acac）₂. In addition, we haveinvestigated the electrochemical intercalation properties with Li+of thesynthesized two different phases of1D vanadium dioxide. It was foundthat the nanorod VO₂（B） electrode possesses better electrochemicalperformance in lithium ion batteries compared with nanosheet VO₂（A）electrode, which is consistent with the tunnel structure in theircrystallographic structure.