| New nano-composite is a new material with broad prospect in the fields ofmaterials science and engineering. The preparation of core-shell structuralnanoparticles and supported nano-composites according to people’s intend, andfurther reveal their new properties and principles have become one of the hot researchareas. In this dissertation, we reported a new synthetic route and self-assemblymethods to prepare a series of novel nano-composites. And their formationmechanism, structure features, physical and chemical characteristics were researchedsystematically. Furthermore, the catalytic principle and properties of glucose, H2O2and hydrazine hydrate on the nonenzymatic electrochemical sensor were furtherinvestigated through electrochemical experiments. The following researches havebeen carried out：1. With Au nanoparticles for seeds and without any surfactant, the flower shapeAu@Pd nanoparticles were prepared by seed-mediated growth method, the clustershave a core diameter of~20nm and a shell average thickness of~3nm. Ionic liquidsacted as bridge connecting Au@Pd one another and bucky gel as platform within thewhole nanocomposite, and a novel nonenzymatic glucose sensor was reported. TheFS Au@Pd nanoparticles was a good candidate for the catalytic efficiency ofnanometallic surfaces because of its flower-shaped nature, which has greater surfacearea and adsorption capacity, the most important is their surface is positively charged,profitting the oxidation process of glucose. Furthermore, Pd coated Au core-shellnanoparticles can enhance electrocatalytic activity, provide selective biofunctionaliza-tion docking points, and improve biocompatibility. So the modified electrode hashigher sensitivity, selectivity, stability and repeatability than other modified electrodes,the glucose oxidation current is linear to its concentration in the range of5nM~0.5μM, and it’s detection limit was found to be1.0nM (S/N=3).2. TiO2nanotubes were prepared by hydrothermal treatment of TiO2powders inconcentrated NaOH solution at140℃for24hours, which with high surfacearea(184.9m2/g) and adsorption ability are introduced as catalyst support to load metal nanoparticles(MNPs). Here, we present a simple strategy for surfacemodification of TiO2nanotubes by3-ami-nopropyltrime thoxysilane to prepare afunctionalized TiO2nanomaterial (f-TiO2NTs), which is positively or negativelycharged in different pH conditions and offer versatile solid supports for FS Au@Pdand Au nanostructures. Therefore, a series of novel supported nano-compositesprepared by self-assembly method. The loaded Au@Pd NPs didn’t change the porestructure of TiO2NTs, but increases the catalyst activice area of the supportednano-composites. In this dissertation, H2O2and hydrazine hydrate were selected asprobe molecules to investigate the photoelectrocatalysis property of f-TiO2NTs-Au@Pd nanocomposites. This result indicates that the overall electrochemical reaction ofH2O2at the modified electrode might be controlled by the diffusion process, the H2O2reduction current is linear to its concentration in the range of1×10-7~5×10-4M, andit’s detection limit was found to be2×108M(S/N=3). The hydrazine hydrate might becontrolled by adsorption process and the rate-determining step is a one-electronreaction, the hydrazine hydrate oxidation current is linear to its concentration in therange of5×10-9~5×10-7M, and it’s detection limit was found to be1.0×10-9M.3. An easy surface-modified method has been developed to link PDDA to theTiO2nanotubes through ultrasonic vibration. The functionalized TiO2nanotubes arepositively charged and offer versatile solid supports for PdCl42-. Then based on PdNPs-PDDA-TiO2NTs/GCE nonenzymatic glucose sensor was prepared by subsequentchemical reduction of the precursor in NaBH4aqueous solution. The results indicatedthat the proposed approach provided a highly sensitive, good anti-poisoning ability,wide linear range, more facile method and good reproducibility for glucosedetermination, promising the development of Pd-based material in nonenzymaticglucose sensing. The electrocatalytic mechanism is that Pd(OH)xwere formed inalkaline solution, which is beneficial in oxidizing the poisoning intermediates derivedfrom the glucose electroadsorption. This process released free active PdNP sites forthe direct oxidation of glucose. Furthermore, The electrochemical results suggest thatthe nonenzymatic glucose senser have a good linear relationship between anodic peakcurrent and glucose concentration was obtained in the range of4×10-7~8×10-4M withthe detection limit of8×10-8M(S/N=3). |
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