Synthesis And Electrochemical Application Of Porous Metal Nanoparticles

As a novel species of material, nanomaterials are widely used in many applications, such as sensors, catalysis and optics. These properties are closely related to their morphology structures, especially some new nanomaterials with opening holes structures. As a subset of nanostructured porous materials, nanoporous metals with highly ordered networks and uniform poresize distributions have important practical applications in the field of electrochemical sensors. Porous metal nanoparticles, a novel nanostructure, both having nanoporous structure and nanosize can not only increase the active area accessible to the target molecules but can also improve electron mobility. Electrochemical sensors with high sensitivity can be fabricated by taking these advantages of the porous metal nanoparticles.There are two research sections for this thesis:1. Ag NPs were deposited on ITO surface by cyclic voltammetry. Then Au PNPs were prepared by galvanic replacement reaction. The Au PNPs on ITO substrate were characterized by means of UV-vis spectroscopy, scanning electron microscopy(SEM), atomic force microscopy(AFM), cyclic voltammetry(CV), and X-ray diffraction(XRD). Based on the Au PNPs/ITO working electrode, the responsibility of the sensor to Hg2+ by differential pulse anodic stripping voltammotry(DPASV) was symmetrically studied. A calibration curve form 0.1 to 10 μg/L Hg2+ was obtained under the optimization condition. The detection limit was 0.03μg/L at a signal-to-noise ratio of 3. The performance of the proposed electrode was also applied in detection trace Hg2+ in different real samples with satisfactory results.2. Porous Au-Pt NPs were prepared by galvanic replacement reaction. Firstly, the Au-Ag NPs/ITO electrode was prepared by galvanic replacement reaction between Ag PNPs /ITO electrode and HAuCl4. Then the Au-Pt PNPs /ITO electrode was synthesized by further reacting with H2PtCl6. The catalytic properties to direct electrochemistry oxidation of H2O2 of the Au PNPs /ITO electrode and the Au-Pt PNPs /ITO electrode was compared. The results indicated that the Au-Pt PNPs /ITO electrode showed a much higher electrocatalytic efficiency and detection sensitivity to H2O2 compared to the Au PNPs /ITO electrode.The Au-Pt PNPs /ITO electrode exhibited a liner range from 0.002 mM.to 3 mM with a detection limit of 0.6 μM at a signal-to-noise ratio of 3. The proposed electrode thus is promising to detect the real samples.