Peculiarities of surface layer formation at galvanic displacement of lead by platinum. Activity of Pt0(Pb) composites in FAOR
| Autor: | Yu. M. Maksimov, Boris I. Podlovchenko |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Chemistry
General Chemical Engineering chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Analytical Chemistry X-ray photoelectron spectroscopy Desorption Electrochemistry Galvanic cell Surface layer Composite material 0210 nano-technology Polarization (electrochemistry) Platinum Displacement (fluid) Order of magnitude |
| Zdroj: | Journal of Electroanalytical Chemistry. 801:319-327 |
| ISSN: | 1572-6657 |
| DOI: | 10.1016/j.jelechem.2017.08.002 |
| Popis: | Galvanic displacement (GD) of lead (e.d. Pb/GC) by platinum in 10 − 3 М K 2 PtCl 4 + 0.1 M HClO 4 solution is carried out. The formation of Pt 0 in the course of GD at Е + → Pb 2 + + Н 2 . The deposit formed at GD (Pt 0 (Pb) in ) is modified by potential cycling in the Е interval of 0.05–1.45 V (1–20 cycles). All the samples are characterized by SEM, EDX, XPS, AES-1CP, and CVA methods. It is shown that no dense Pt shell is formed in the synthesis of Pt 0 (Pb) in . This is explained by the fact that at the stationary potential Е st established at GD, Pb ad fails to desorb completely from the Pt 0 surface. A scheme of partial incorporation of Pb ad into the surface layer of Pt 0 (Pb) in is put forward. After 20 potential cycles, the Pb content in the first atomic layer on the Pt 0 (Pb) 20c surface becomes insignificant. Nonstationary (CVA) and stationary polarization measurements in the 0.5 М НСООН + 0.1 М HClO 4 solution demonstrate the very high activity of Pt 0 (Pb) composites in FAOR. Thus, in the low Е range (0.2–0.3 V), which is the region most interesting for practice, the specific stationary currents on Pt(Pb) in composites exceeds the analogous currents on e.d. Pt by two orders of magnitude. However, the activity of Pt 0 (Pb) 20c turns out to be only ~ 3 times higher than the activity of e.d. Pt. The possible reasons for the observed high activity of Pt 0 (Pb) composites in FAOR and instability of their characteristics are discussed. |
| Databáze: | OpenAIRE |
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