Dynamics of surface alloying promoted by cadmium underpotential deposition-anodic stripping cycles on irregular silver electrodeposits
The underpotential deposition of Cd from dilute aqueous 5 × 10<sup>−3</sup> M CdSO<sub>4</sub> + 0.5 M Na<sub>2</sub>SO<sub>4</sub> + 0.01 M H<sub>2</sub>SO<sub>4</sub> on Ag electrodeposits grown on polyfaceted Pt single-crysta...
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| Autores principales: | , , , |
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| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
1994
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/119361 |
| Aporte de: |
| Sumario: | The underpotential deposition of Cd from dilute aqueous 5 × 10<sup>−3</sup> M CdSO<sub>4</sub> + 0.5 M Na<sub>2</sub>SO<sub>4</sub> + 0.01 M H<sub>2</sub>SO<sub>4</sub> on Ag electrodeposits grown on polyfaceted Pt single-crystal microspheres was studied using potentiodynamic and potentiostatic techniques, transmission electron diffraction, scanning tunneling microscopy and X-ray photoelectron spectroscopy. Ag electrodeposits were grown in 5 × 10<sup>−3</sup> M Ag<sub>2</sub>SO<sub>4</sub> + 0.5 M Na<sub>2</sub>SO<sub>4</sub> + 0.01 M H<sub>2</sub>SO<sub>4</sub> at cathodic overpotentials η<sub>c</sub> of −0.06 V and −0.58 V to form a columnar and dendritic Ag surface respectively. Surface rearrangement processes involving the formation of Cd + Ag alloys were studied by stripping voltammetry after the potential was held for a certain time at different preset values covering the potential range in which the degree of surface coverage by Cd atoms was less than or close to unity (θ<sub>c</sub>⩽ 1) on both Ag surfaces. Surface diffusion and penetration of Cd atoms into bulk Ag for θ<sub>c</sub>⩽ 1 are discussed. A place-exchange mechanism is advanced to account for the kinetics of Cd + Ag alloy formation. |
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