Electrochemical And Optical Properties Of Noble Metal Materials

The synthesis, properties study and application in various fields of noble metal nanomaterials is a hot research topic recently, various new types of nanostructures, the specific composition of nanocomposites as well as the innovation of the construction methods has been a steady stream of report. In many unique properties of nanomaterials, catalytic properties and optical properties have been a universal attention by researchers, while noble metal nanomaterials have a wide range of applications used in alcohol fuel cells, biological sensors and surface enhanced Raman scattering, etc. In this paper, we used the electrodeposition method and the hydrothermal synthesis method to have the success of the preparation of palladium based bimetal thin film electrode and silver base metal materials, discussed the influence in electrochemical and optical properties of metal materials under different conditions, studied their applications in direct methanol fuel cell, nonenzymatic electrochemical glucose biosensor and surface enhanced Raman spectroscopy. The main contents include the following three parts:Part one:the preparation of palladium-based bimetallic thin film electrodes by electrodeposition and the oxidation of methanolWe prepared palladium-iron, palladium-cobalt and palladium-nickel porous thin electrodes through the direct electrochemical deposition method on the activated glassy carbon electrode, focused on the influence of the structure of porous thin film electrode by changing metal composition of deposited solution in this method, tested its electrochemical behavior in the alkaline methanol solution by using cyclic voltammetry. At last, we choosed the best direct electrochemical deposition reaction conditions through the comparison of electrochemical behavior on porous palladium based thin film electrode synthesized under different reaction conditions and tested at different conditions. For palladium iron thin film electrode, when the palladium content was90%, the current density of the oxidation peak reached maximum value77.63mA cm-2; For palladium cobalt thin film electrode, when the palladium content was90%, the current density of the oxidation peak reached maximum value35.81mA cm-2; For palladium nickel thin film electrode, when the palladium content was80%, the current density of the oxidation peak reached maximum value43.31mA cm-2; but the current density of the oxidation peak of the palladium thin film electrode that has the same metal content was23.06mA cm-2and the current density of the oxidation peak of the standard palladium electrode was0.86 mA cm-2. It can be seen that the catalytic capability of bimetallic palladium based electrode is better than the pure palladium electrode, and in the different bimetallic system, the palladium iron thin film modified electrode had the best electrooxidation effect for methanol in alkaline medium.Part two:reserch of the nonenzymatic glucose electrochemical sensor loaded highly dispersed palladium nanoparticles based on PS templateUsing PS spheres as the template, we researched to synthetize the modified electrode highly dispersed Pd nanoparticles by electrodeposition and synthetised the electrochemical sensor that has strong selectivity and high sensitivity. First, we droped the homogeneous dispersed PS spheres, nanoparticles electrodeposited can be highly dispersed in the gap of PS spheres and around, have very good stability and dispersion. Then loaded palladium particles on the template by electrodeposition method, finally removed the template to get the modified palladium electrode. As a sensor interface, we studied the enfluence to the selectivity of glucose test by the detection potential and the amounts of PS layer, in determining the optimal experimental conditions. Finally, we realized the high sensitivity and high selectivity of nonenzymatic glucose detection successfully, and the test based on the actual samples show that the method for real-time detection of glucose is feasible.Part three:the reserch of Surface Enhanced Raman Scattering on silver thin film substrate made by hydrothermal synthesisWe deposited silver substrate material on titanium plate by hydrothermal synthesis method, focused the enfluence to porous strcture of silver by the changing of the composition of base solution, and detected the Raman intensity of R6G on silver nanoparticles synthesized by using Raman spetroscopy. We discussed R6G adsorption properties through the contrast of Raman intensities under different conditions on silver nanomaterial synthesized. It was found that when the ratio of the silver nitrate and ammonia joined respectively is1:3, it has the best effect of Raman enhancement. The research results of this chapter show that the Ag/TiO2substrate of porous structure has a good application prospect in the study of adsorption properties of R6G and is expected to have wide development in life science field.