Direct Observation of Ion Pairing at the Liquid/Solid Interfaces by Surface Enhanced Raman Spectroscopy
| Autor: | Charles B. Nettles, Dongmao Zhang, Shengli Zou, Yadong Zhou, Ganganath S. Perera, T. Keith Hollis |
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| Rok vydání: | 2015 |
| Předmět: |
Chemistry
Analytical chemistry Metal Nanoparticles Nanoparticle Ionic bonding Surfaces and Interfaces Electrolyte Surface-enhanced Raman spectroscopy Spectrum Analysis Raman Condensed Matter Physics Phase Transition Ion Electrolytes Adsorption Colloidal gold Chemical physics Electrochemistry Molecule General Materials Science Gold Spectroscopy |
| Zdroj: | Langmuir. 31:8998-9005 |
| ISSN: | 1520-5827 0743-7463 |
| Popis: | Ion-pairing, the association of oppositely charged ionic species in solution and at liquid/solid interfaces has been proposed as a key factor for a wide range of physicochemical phenomena. However, experimental observations of ion pairing at the ligand/solid interfaces are challenging due to difficulties in differentiating ion species in the electrical double layer from that adsorbed on the solid surfaces. Using surface enhanced Raman spectroscopy in combination with electrolyte washing, we presented herein the first direct experimental evidence of ion pairing, the coadsorption of oppositely charged ionic species onto gold nanoparticles (AuNPs). Ion pairing reduces the electrolyte concentration threshold in inducing AuNP aggregation and enhances the competitiveness of electrolyte over neutral molecules for binding to AuNP surfaces. The methodology and insights provided in this work should be important for understanding electrolyte interfacial interactions with nanoparticles. |
| Databáze: | OpenAIRE |
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