Electrochemical deposition of Cobalt, Nickel-Cobalt, Nickel-Copper and Zinc-Nickel nanostructured materials on aluminium by template self-organization [article]

Adolphe Foyet, Martin-Luther Universität, Universitäts- Und Landesbibliothek Sachsen-Anhalt
In the present work, a thin aluminum oxide was prepared on aluminum by double anodization of the aluminum foil in 0.3 M oxalic acid. The influence of the electrolyte (oxalic acid) temperature on the structure of alumina membrane was studied. The membrane anodized at 10 °C had a long-range organization of hexagonal pores with uniform diameter. Highly ordered cobalt and alloy nanomaterials were deposited from aqueous solution into the pore of this alumina membrane with intact barrier layer.
more » ... arrier layer. Nanorods of about 1.2 µm in length with a periodicity (center-to center spacing between two close particles) of about 125 nm were grown in the pores of aluminum oxide. The combination of this alumina membrane with a lyotropic liquid crystal containing metallic ions (double template deposition) leads to materials with many substructures. Many columns of liquid crystals went into one pore of alumina; after deposition and removal of the surfactant, the nanorods showed many subdivisions. Two surfactants with different molecular size were investigated; the hexagonal phase of a non ionic surfactant (Brij 78) with a diameter of columns close to 8 nm and that of an ionic surfactant (CTAB) with smaller (Φ ~ 4 nm) columns. The film deposited from CTAB consisted of very small nanoparticles and their corrosion potential shifted to more negative value. The polarization curves gave various peaks characteristic of metal oxidation in the case of single element (Cobalt) or phase transition during alloy oxidation in the case of multiphase alloy such as ZnNi. The impedance curves were typically characteristic of porous electrodes. The Mott-Schottky analysis of the space charge capacitance data revealed that the films of metal or alloy nanomaterials behave like semiconductor with high dopant (oxygen vacancies or cation vacancies) concentration.
doi:10.25673/2740 fatcat:gzkc5435ibeu5msp5nndccmyfu