مشخصات پژوهش

The formation of platinum nucleus on the freshly polished aluminum (Al) and anodized aluminum electrodes (Al2O3/Al) was studied by cyclic voltammetry. Results showed that the deposition of platinum on freshly polished aluminum from an aqueous 0.5M phosphate buffer solution containing H2PtCl6 takes place rapidly through the electroreduction of dissolved Pt (IV) ions. At shorter deposition times, small particles of platinum crystals were formed on the aluminum and the surface coverage was imperfect. At longer deposition times, the size of the platinum crystals increases while their number decreases due to the coalescence and agglomeration processes. The electrodeposition of Pt on the Al electrode was conveniently carried out over the Al2O3/Al electrode. The electrochemical and catalytic activities of the Pt/Al and Pt/Al2O3/Al electrodes were studied in 0.1M H2SO4 solution. In cyclic voltammetry, the two pair symmetric peaks appeared in 0.1M H2SO4 solution which was attributed to the formation of strongly (Hs) and weakly bounded hydrogen (Hw). The occurrence of the third anodic hydrogen peak (H3rd) was revealed at low scan rate and in high concentration of H2SO4. At potentials more negative than 0.3V vs. SCE, the current is mainly due to hydrogen evolution reaction. The influence of the various parameters such as deposition method and amount of platinum, sulfuric acid concentration and medium temperature on the hydrogen evolution reaction is described. Finally the kinetic of the hydrogen evolution reaction is also discussed on the Pt/Al electrode.