Measurement Procedures for EC-SERS

Electrodes Solution composition CV measurement Defining potentials of interest 

Molecules (or ions) of interest in liquid (solid) sample and in electrolyte solution Assigning the main vibrational modes 

Before starting a new EC-SERS study, it is important to first obtain the normal Raman spectrum of the species in its original form, such as the pure hquid or solid. In addition, spectra should be collected for theexpected produces) of the electrode reaction to be studied. The Raman spectra of the molecules/materials in the solution to be measured during the in-situ study should then be recorded. These good-quality spectra will serve as references to compare with the surface Raman spectra. If the spectrum is too complex, an isotopic study will be very helpful for identifying the vibrational modes. Before the EC-SERS study, it is important to define the electrochemical behavior to obtain the characteristic potential for use in the in-situ EC-SERS study. 

For some systems, there is no resonance Raman or SERS effect to be utilized, and the sensitivity becomes the main problem. In this case, a potential difference method will be of great help [11], Here, a spectrum is acquired at potentials where there is no or only a weak surface signal which is subtracted from that at the potential of interest. In addition, a change in the composition of the electrolyte or an isotopic labeling experiment may be considered to identify the surface species and verify its orientation and structure. For temporally resolved studies, electrochemical transient techniques are helpful to understand the surface dynamics and the reconstruction processes of surfaces. For nonuniform surfaces, spatially resolved measurements provide more reliable and complete information on the surface. This is also useful for electrode surfaces that change either chemically or topographically in a microzone upon variation of potential. 

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