1,10-Phenanthroline Adsorption on Iron Electrode Monitored by Surface-Enhanced Raman Scattering (SERS). Comparison to SERS of Phen and Its Transition Metal Complex on Silver Electrode

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• 作者：Gustavo F. S. Andrade ; Marcia L. A. Temperini
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：September 20, 2007
• 年：2007
• 卷：111
• 期：37
• 页码：13821 - 13830
• 全文大小：393K
• 年卷期：v.111,no.37(September 20, 2007)
• ISSN：1932-7455

文摘

The SER spectra of 1,10-phenanthroline (phen) adsorbed on Fe electrode in chloride medium as a functionof applied potentials at 632.8 and 514.5 nm excitation wavelengths are presented. SERS spectra of phen onCo and Ni electrodes at 632.8 nm are also shown. The SER signatures of the surface complex indicate itssimilarity with the chemically prepared [M(phen)₃]²⁺, where M = Fe²⁺, Co²⁺, or Ni²⁺. The same changes inrelative intensities of the bands with applied potential are observed for phen on transition metals and for[M(phen)₃]²⁺ on silver electrodes. These spectral changes at 632.8 nm excitation radiation resemble the spectralchanges in the resonance Raman spectra of [M(phen)₃]Cl₂ at different excitation laser lines. At the potentialof maximum intensity, the strongest band in phen on Ag SER spectrum is ca. 70 times higher than that inphen on Fe, while the phen on Fe SER excitation profile is ca. 5 times higher than that of phen on Ag. At632.8 nm radiation, the band at 557 cm^-1 for phen on Fe shows the highest profile in SER excitation profiles,while for phen on Ag the most enhanced band is at 1578 cm^-1. These results indicate that the CT excitedstates in phen on Fe and phen on Ag are different and that the SER CT mechanism in phen on Fe is moreeffective. The magnitude and dissimilarities in the [Fe(phen)₃]Cl₂ resonance Raman profiles as compared tothe SER excitation profiles of [Fe(phen)₃]²⁺ on Ag emphasize the different origins of the two enhancementprocesses.