Studies On Surface-Enhanced Raman Scattering In Electrochemical System

Surface Enhanced Raman Scattering (SERS) is sensitive for in situ studying of orientation of molecules adsorbed on the substrate and probing of interfacial phenomena. SERS technology, using silver, gold, or other noble metals as substrates, has been a powerful and sensitive instrumental tool for obtaining detailed information of adsorbed molecules, such as the adsorption configuration of molecules and the interaction mechanism of the molecules with the surface of the substrate. It is well known that potential is an important factor influencing surface adsorption and reaction. The adsorption behavior of the adsorbate on the substrate would be greatly affected by the surface configuration of the adsorbate and the applied electrode potential in electrochemically system. At the same potential, if the surface configurations of adsorbates are different, the adsorption patterns of the adsorbates may be different though the composing of them is same. At different applied potential, the adsorption behaviors of the same adsorbates are also probably different.The potential-dependent surface-enhanced Raman spectrum of adsorbed p-nitrobenzoic acid (PNBA) on the roughened Au electrode has been obtained by using ultraviolet (UV) excitation at 325 nm. The surface-enhanced Raman spectra of PNBA intensely changed when the voltage was in the rang of negative value, and the electrode potential at which the resonance (potential of maximum intensity) occurs varied when the vibrational mode changes, indicating that the PNBA molecules were chemisorbed on the roughened Au surface. The charge transfer (CT) mechanism could probably explain the experiment results in the present work.Due to small solubility, It is difficult to research SERS in water for some molecule. Other substance, even if dissolved in water, but oxidation and deoxidize don't study enough because of limited voltage range.If we choose right solvent, then we will extend voltage range and avoid effect due to divided hydragen and oxygen. So, it is important to study SERS in water for remedy shortage of conventional electrochemistry.