Preparation Of TiO₂ Nanowires And Applied In H ₂O₂ Sensor And Lithium Ion Batttery

One-dimensional (1D) nanostructure semiconductor materials, which have excellent physical and chemical properties due to the shape anisotropy, have attracted worldwide attention. As a typical semiconductor, 1D TiO₂ nanomaterial has been researched extensively in many fields because of its inexpensive, non-toxic, chemical stability and other perfect physical and chemical performance. However, so far few publications reported the application of titania-nanowires (TNWs) in biomolecule immobilization and biosensor construction. In this thesis, TNWs were prepared by modified hydrothermal method. A H₂O₂ biosensor was fabricated based on TNWs. Furthermore, the electrochemical performances of TNWs were also studied as an anode material of lithium ion battery. The details are summarized as follows.In chapter 2, TNWs with diameter about 50 nm were synthesized with modified hydrothermal method. The morphology of TNWs was characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM). Crystal structural characterization of TNWs was performed by X-ray diffraction (XRD). Then, a H₂O₂ biosensor was prepared based on coimmobilized of TNWs and horseradish-peroxidase on glassy carbon electrode (GCE) with the help of chitosan (CHIT). The experimental parameters were optimized for best analytical performance. Under optimum conditions, the H₂O₂ biosensor showed a linear response to H₂O₂ in the concentration range of 4μM to 1.15 mM. The sensitivity of the biosensor to H₂O₂ was calculated to be 124μA mM^-1 cm^-2 and the detection limit was calculated as 0.32μM based on signal/noise = 3 with a correlation coefficient of 0.99996. The response time of the biosensor was less than 3 s. The apparent Michaelis-Menten constant were 4.31 mM. In summary, the biosensor with low detection limit, fast response, wide detection range and high sensitivity was a promising sensor for the online determination of H₂O₂.In chapter 3, we prepared the TNWs by hydrothermal processing. The effect of H₂O₂ processed on the morphology and element composing of TNWs was examined by Digital Camera (DC), SEM, XRD and EDS. We also investigated the effect of anneal on the morphology and element composing. The results indicated that the raw TiO₂ particles with anatase transfered to TNWs with TiO₂-B. TNWs were of good thermal stability, H₂O₂ processing and anneal could not effect the morphology of TNWs, but they can modify the element composing. After processed by H₂O₂, the O/Ti of TNWs rose. However, it decreased after TNWs annealed. Lastly, the electrochemical performances of TNWs were further explored in terms of their potential application as anode materials for lithium-ion batteries. TiO₂ nanowires without H₂O₂ processed exhibited the largest discharge capacity up to 124 mA h/g at a current density of 20 mA/g at 1-3 V versus Li⁺(1 M)/Li and retained 55 mA h/g over 30 cycles. The largest discharge capacity of TiO₂ nanowires with H₂O₂ processed and raw TiO₂ powder were 120 mA h/g and 108 mA h/g. The discharge capacity of all of the TiO₂ materials underwent an enhancement and decreasement with the cycle number rising.