Galvanic displacement and electrochemical leaching for synthesizing Pd-Ag catalysts highly active in FAOR
| Autor: | Boris I. Podlovchenko, Konstantin I. Maslakov, Dmitry S. Volkov, Stanislav A. Evlashin, Yu. M. Maksimov |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Chemistry
Supporting electrolyte General Chemical Engineering Inorganic chemistry Metallurgy chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry Catalysis X-ray photoelectron spectroscopy Galvanic cell 0210 nano-technology Polarization (electrochemistry) Dissolution Palladium |
| Zdroj: | Journal of Electroanalytical Chemistry. 788:217-224 |
| ISSN: | 1572-6657 |
| DOI: | 10.1016/j.jelechem.2017.02.012 |
| Popis: | The galvanic displacement (GD) of a silver electrodeposit on gold by palladium (displacing agent – Pd2 +) is carried out. The resulting composite Pd0(Ag)in is subjected to potential cycling in the supporting electrolyte (0.5 М Н2SO4) solution (1–3 cycles) in the Е interval 0.09–1.4 V (RHE). All samples are characterized by SEM, XPS, AES-ICP, and CVA methods. The GD fails to produce a Pd shell, which is explained by the fact that Ag adatoms are incorporated into the surface layer on the top of Pd0 and cannot be substituted by Pd2 +. Potential cycling of the initial deposit Pd0(Ag)in results in preferential dissolution of Ag; however, no sufficiently dense Pd shell is formed. Stationary polarization curves at Е < 250 mV (vs RHE) in 0.5 М Н2SO4 + 0.5 М НСOОН solution reveal the very high specific activity for all Pd0(Ag) composites (per cm2 of EASA) in FAOR, 5–10 times exceeding the activity of electrodeposited (e.d.) Pd. The promotion of Pd by Ag additions was explained by both the inhibition of formation of chemisorbed species and the development of new active sites at the Pd/Ag boundary. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect