| Autor: |
Boulares, Asma, Dhouibi, Leila, Berçot, Patrice, Rezrazi, El |
| Zdroj: |
Chemistry Africa; December 2018, Vol. 1 Issue: 3-4 p127-144, 18p |
| Abstrakt: |
The elaboration of titanium oxyhydroxide/manganese oxide composite on pure copper was made through a cathodic electrodeposition by local pH variations for depositing titanium oxyhydroxide and a cathodic reduction for depositing manganese oxide. The structural and morphological techniques [scanning electron microscopy (SEM) coupled with dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GD-OES)], show that the films have a nodular structure with a co-distribution of titanium and manganese on the copper surface. The dispersion of the doping reagent, namely manganese oxide in the doped precursor titanium oxyhydroxide forming thereby the composite, is confirmed by XRD spectra by the low crystallinity of titanium oxyhydroxide and the absence of diffraction peaks relative to manganese oxide. The electrochemical behaviors of bare copper and copper surface modified by the composite were compared in 3% NaCl medium. The linear polarization and cyclic voltammetric curves show that copper substrate reacts as an antioxidant by preventing the composite oxidation even at very anodic potentials. The electrochemical impedance spectroscopy (EIS) proves that copper contributes through its passive behavior, to the improvement of the stability of the composite over time in chloride medium. |
| Databáze: |
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