Syntesis And Electrochemical Performance Of Transition Metal (Oxide) Based Nanomaterials

Among the numerous nanomaterials, metal or metal oxides based nanomaterialshave been extensively applied in various research fields due to their superiorcharacteristic of simple preparation, controllable morphology, high mechanicalstrength and strong electrocatalytic activity. Carbon nanomaterials also attractedconsiderable interest in electrochemistry aspect since their high surface area, excellentelectric conductivity, and be facilitate to functionalization. When coupled with othernanomaterials, carbon nanomaterials can serve as the substrate to fasten thenanoparticles and prevent them from aggregating. In this thesis, we designed toprepare a series of nanocomposites with specific structure and function as electrodematerials for constructing electrochemistry sensors or supercapacitors. The mainworks include the following three parts:1. A novel nonenzymatic hydrogen peroxide （H2O₂） sensor based on Ptnanoparticles （Pt NPs） deposited on Ni foam was simply prepared by UV-irradiation.Scanning electron microscopy was applied to characterize the changes ofmorphologies with deferent time of UV-irradiation. Energy dispersive spectroscopyconfirmed that the main components of the Pt NPs-Ni foam were Pt and Ni. This PtNPs-Ni foam composite electrode combined the high electric conductivity, largesurface area, high porosity of Ni foam and the strong electrocatalytic activity of PtNPs. Its application in H2O₂detecting, surprisingly, showed the high sensitivity andlow detection limit.2. A simple strategy for synthesis manganese dioxide nanoparticles （MnO₂NPs）loaded on Carbon nanofibers （CNFs） was designed by combining electrospinningtechnique and thermal treatment. Scanning electron microscopy images showed thatthe surface of the CNFs was decorated with a large number of homogeneous MnO₂nanoparticles. For the strong catalytic oxidation ability of MnO₂towards hydrogenperoxide, the composite material was used as the matrix for nonenzymatic sensorconstruction. The resulted sensor displayed good performance along with highsensitivity, wide linear detection range and low detection limit, which could beattributed to the large surface area and excellent electrocatalytic activity of theMnO₂NPs-CNFs.3. A green method for fabrication reduced graphene oxide （RGO）/nickel cobaltite （NiCo₂O₄） nanoflake composites were designed by combining in situ assembling andthermal treatment. Scanning electron microscopy images showed that the compositeswere constituted with many ultrathin nanoflakes. For the binary redox couples(Ni²⁺/Ni³⁺and Co²⁺/Co³⁺) of NiCo₂O₄, the RGO/NiCo₂O₄was used as the electrodematerials for capacitance testing. The resulted electrode achieved high specificcapacitance, good rate capability and long-term cyclability, which could be attributedto the large surface area, superior conductivity and the rich redox couples of theRGO/NiCo₂O₄.