Underpotential Co-deposition of Cu1-xPtx Alloys
| Autor: | William F. Egelhoff, Alexander J. Shapiro, Ugo Bertocci, Jonathan J. Mallett, Thomas P. Moffat, Erik B. Svedberg, John Bovevich |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | ECS Transactions. 2:315-328 |
| ISSN: | 1938-6737 1938-5862 |
| Popis: | The electrodeposition of Cu1-xPtx alloys by underpotential co- deposition of Cu with Pt is demonstrated using an H2SO4-CuSO4- PtCl42- electrolyte. The composition and structure of 1 micrometer thick alloy films grown at different potentials were examined by EDS, XRD and TEM. A thermodynamic rational for the alloying process is provided by a symmetrical regular solution model whereby underpotential co-deposition of Cu is ascribed to the negative enthalpy of mixing with Pt. The observed dependence of alloy composition on potential is in good agreement with equiatomic mixing enthalpy of -18 kJ/mol, obtained from calculations by Miedema et al. An EQCM was used to provide a time resolved assessment of the alloy formation process. Simultaneous measurement of the mass and current transients during potential steps enable the effects of submonolayer underpotential deposition of Cu onto a Pt rich surface to be observed and separated from the subsequent steady-state co-deposition of Cu with Pt. |
| Databáze: | OpenAIRE |
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