Preparation And Electrocatalytic Properties Of Gold And Platinum Nanostructured Films

Nanostructured thin-films have been widely used in various fields such as medical diagnosis, catalysis and sensing because of their unique optical, mechanical, electromagnetism and gas-sensitive properties. Among the preparation methods of nanostructured thin-films, self-assembly and electrodeposition have attracted much more attention of research workers due to their simpleness and convenience. Thus, this thesis involves assembly of gold-platinum core-shell nanoparticles and electrodepositon of gold and platinum, attempting to develop controllable preparation techniques of nanostructured thin-films. In addition, electrocatalytic behavior of part of as-prepared nanostrucured films was also systematically studied. The main research contents are summarized as follows:1. Gold-platinum core-shell nanoparticles with different diameters were synthesized and assembled into monolayer film arrays. Scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and electrochemical techniques were exployed to characterize as-prepared monolayer films. In the study of methanol electrooxidization, the optimized Au-Pt core-shell array showed excellent electrocatalytic properties: the mass-normalized current density is about 11 and 40 times better than that of the non-array electrode and the commercial Pt/C electrode.2. The hierarchical dendritic gold microstructures （HDGMs） were fabricated by chronopotentiometry in a self-made electrolytic cell. The surface morphologies and roughness of as-prepaed HDGMs were characterized by SEM and contact angel measurements. The optimized HDGMs exhibited an excellent electrocatalytic activity towards the reduction of hydrogen peroxide （H₂O₂） and were used for H₂O₂ detection. The detection linear range and the detection limit were 2.4×10-5 7.2×10-3 mol·dm-3 and 1.2×10-5 mol·dm-3 （S/N=3）, respectively, exhibiting a satisfactory sensitivity and stability.3. Uniform Pt nanostructured thin-films were elctrodeposited by sepereating nucleation and growth of Pt, and the fine control of microstructure of Pt nanostructrued thin-films was achieved by using SiO2 particle film as a blocking layer. The primary study indicates that SiO2 particle film can effectively control the density and distribution of Pt nanopartiles in the resulting Pt nanostrutured thin-films by physical confinement.