The reorientation of benzonitrile on Platinum electrode probed by surfaceenhanced Raman spectroscopy

摘要

The adsorption and reorientation behavior of benzonitrile on an electrochemical roughened Pt electrodewere studied by surface-enhanced Raman spectroscopy (SERS) over a wide potential range. The resultsrevealed that benzonitrile was adsorbed on the surface in a vertical orientation through the nitrogenatom of CN group in the relative positive potential region (>-0.6 V), while the benzonitrile moleculechanged its orientation with the negative movement of potential (<-0.8 V). In the hydrogen evolutionregion, the intensity of the Raman bands from the benzene ring and CN group decreased dramatically,and the frequency of CN red-shifted about 160 cm~(-1). It indicated that the benzonitrile was adsorbedon the Pt electrode in a flat orientation by interacting with the electrode surface via CN and/or benzenering. A schematic model about the adsorption configurations of benzonitrile in different potential regionswas proposed.