表面增強拉曼散射(SERS)是一種在一系列電化學應用中研究納米尺度分子-金屬界面的有力工具。表面增強拉曼散射將分子水平的信息和高度的表面特異性結合在了一起,使其成為了了解界面過程的理想手段。從了解分析物和電解質如何在金屬表面附近結合到實時觀測表面調控的反應,都可以進行觀測。然而,由於表面增強拉曼散射依賴於局部表面等離子體激元的激發,因此產生如熱電荷載流子和光熱加熱等額外效應,進而會影響電化學表面增強拉曼散射信號。當使用表面增強拉曼散射進行定量電化學研究時,這些效應必須加以考慮。
Surface-enhanced Raman scattering (SERS) is a powerful tool for studying nanoscale molecule-metal interfaces across a range of electrochemical applications. SERS combines molecular-level information with a high degree of surface specificity, making it an ideal tool for understanding interfacial processes, from understanding how analytes and electrolytes organize near metal surfaces to following surface-mediated reactions in realtime. However, because SERS relies on the excitation of localized surface plasmons, additional effects such as the production of hot charge carriers and photothermal heating can impact electrochemical SERS signals. These effects must also be considered when using SERS for quantitative electrochemical studies.
Figure 1. (A) Geometry of NPoMsubstrate for EC-SERS. (B) Changes in dark field scattering spectral properties as the voltage is switched on (shaded region) and off. The red datarepresent transitions between +0.3 V and 0 V, while the blue data represent transitions between −1.2 V and 0 V (vs. Ptpseudo-reference). (C) SERS spectrum of a biphenyl-4-thiol SAM at different voltages.
Figure 2. (A) Schematic and (B)photograph of EC-SERS using a plasmonic liquid marble substrate. (C)SERS is excited by a laser to track redox chemistry of [Ru(NH3)6]3+/2+ inside the plasmonic liquid marble. (D) Cyclic voltammogram, (E) SERSspectra, and (F) SERS intensities during oxidation and reduction. Data associated with [Ru(NH3)6]3+ is shown in blue, while data associated with [Ru(NH3)6]2+ is shown in orange.
Figure 3. EC-SERSof 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMI-TFSI), a room temperature ionic liquid, on a silver nanoparticle electrode. Bands labeled in different colors correspond to the following species: cationicEMI species (black), anionic TFSI species (blue), alkyl sidechains of EMI (pink), new species (red). The peak at 1330 cm−1 is ascribed to reorientation of the EMI cation in the EDL, while the1613 cm−1 peak is assigned as cation reduction.
Figure 4. (A-B) Photoelectrochemicaldeposition of Pt(0) and Pt(IV) onto gold nanoparticles from a solution of Pt(II). Deposition occurs preferentially along the direction of the laser polarization (inset of panel A). (C) SERS confirms that the electrodeposited shell contains PtO2.
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https://doi.org/10.1016/j.coelec.2018.10.005