Raman Spectroscopy of Electrode Surfaces

Abstract

The sections in this article are Introduction History of Raman Spectroscopy Applied in Electrochemistry Normal Raman Scattering and Resonance Raman Scattering Normal Raman Effect Resonance Raman Effect Surface‐enhanced Raman Scattering Experimental Characteristics of SERS Electromagnetic Enhancement Chemical Enhancement Vibrational Properties of Electrode Surface Species Molecular Symmetry of Surface Species Dipole Coupling Electrochemical Stark Effect and the Influence of a Solvent Surface Selection Rules Comparison of Raman Spectroscopy with Infrared ( IR ) Spectroscopy and their Applications in Electrochemistry Experimental Details Instrumentation for Raman Spectroscopy Lasers Monochannel Instruments Multichannel Instruments Fourier Transform Raman ( FT ‐ R aman) Spectrometer Raman Microscope Confocal Raman Microscope Comparison of Different Raman Systems Experimental Setup for Electrochemical Raman Spectroscopy Optical Operation Modes Spectroelectrochemical Cells Electrode Preparation SERS ‐active Electrode Surfaces Non‐ SERS ‐active Electrodes Electrochemical Raman Measurements Measurement Procedures Sensitivity Spectral Resolution Temporal Resolution Single Shot Measurement Pump‐probe Measurement Potential Averaged Raman Spectroscopy ( PARS ) Spatial Resolution Lateral Resolution Vertical Resolution Calculation of the Surface Enhancement Factor ( SEF ) Combined and Hyphenated Techniques Optical Fiber Raman Spectroscopy Hyphenated Techniques of R aman Spectroscopy with SPM Troubleshooting Optical Alignment Interference of Solution Species Interference of Gas Evolution during In situ Measurements Electrode Stability and Potential Reversibility Surface Heating and Damage Fluorescence Elimination Applications Surface Bonding Identification of Different Surface Species Determination of the Surface Adsorption Sites Distinguishing Different Interactions of the Adsorbate with Substrates Surface Configuration Adsorption Orientation Coadsorption of Thiourea and Thiocyanide Surface Water Water Adsorption in Aqueous Systems Water Adsorption in Nonaqueous Systems Surface Reactions Surface Adlayers Batteries and Fuel Cells Lithium Ion Batteries Methanol Fuel Cells Corrosion Passive Films Corrosion Inhibitors Electrodeposition and Surface Processing Electrodeposition Semiconductor Processing Prospective and Future Developments New Surfaces Ordered Nanostructured Surfaces Well‐defined Single Crystal Surfaces New Methods Tip‐enhanced Raman Spectroscopy Near‐field Raman Spectroscopy Surface Enhanced Hyper‐ R aman Spectroscopy ( SEHRS ) Acknowledgments

Theoretical and Spectroelectrochemical Studies on the Adsorption and Oxidation of Glyoxylate and Hydrated Glyoxylate Anions at Gold Electrodes

“…In situ studies of adsorption and reactivity at the metal/solution interface are relevant for the understanding of the electrocatalytic processes operating in fuel cells and in the electrochemical synthesis of different substances. In these studies, the use of in situ vibrational spectroscopies, such as infrared and Raman, can provide valuable and complementary information on some microscopic aspects of adsorption processes such as preferred adsorption sites, bonding geometry, and molecular orientation with respect to the solid surface, as well as on the adsorbate−metal and adsorbate−adsorbate interactions. − Whereas the external reflection infrared experiments allow the use of single crystal electrodes in order to spectroscopically explore structural aspects of the interfacial processes, , the ATR-SEIRAS ,, and SERS techniques provide a significant enhancement of the infrared absorption and Raman scattering by adsorbed species, allowing the detection of weakly absorbing modes and/or low coverage intermediates. Moreover, the ATR-SEIRAS experiments also provide information on the potential-dependent water−metal and water−adsorbate interactions and allows time-dependent studies in the submillisecond range due to the small time constant of the spectroelectrochemical cells used in these experiments. ,, Irrespective of the acquisition mode (internal vs external reflection configurations in the case of the infrared experiments), the correct interpretation of the vibrational data for adsorbed species at metal surfaces gains additional support from the application of density functional theory (DFT) methods, which can be used to calculate vibrational frequencies and intensities for adsorbates .…”

Electrochemical Tip-Enhanced Raman Spectroscopy

“…Once the potential control or electrolyte is disconnected, the interfacial processes will change and the interfacial structure may relax to the state at the open-circuit potential and will be different from the potential of interest. Therefore, there is an increasing interest in developing electrochemical TERS (EC-TERS) for characterization of important interfaces, − especially a scanning tunneling microscopy (STM)-based method, because STM can provide high spatial resolution. As far as we know, there was only one TERS report in liquid but not under EC condition …”

Novel Electrochemical Raman Spectroscopy Enabled by Water Immersion Objective

“…There have been several generations of electrochemical Raman cells since the first type reported by Fleischmann and later by Van Duyne groups, where thick window and ultrathin electrolyte layer were used in their setup. , This type of cell fits for the macro sample chamber with a low numerical aperture and does not work well with the confocal Raman systems. We have systematically investigated the effect of different cell designs on the collection efficiency of Raman signal under electrochemical conditions. ,, In 2000, we developed a new type of EC-Raman cell made of Teflon or Kel-F with a facing up working electrode . In such a design, a thin electrolyte layer, a quartz window, and air were sandwiched between the objective and electrode surface.…”

“…We have systematically investigated the effect of different cell designs on the collection efficiency of Raman signal under electrochemical conditions. 8,21,22 In 2000, we developed a new type of EC-Raman cell made of Teflon or Kel-F with a facing up working electrode. 21 In such a design, a thin electrolyte layer, a quartz window, and air were sandwiched between the objective and electrode surface.…”