Adsorption of 2-mercaptopyridine and 4-mercaptopyridine on a silver surfaces investigated by SERS spectroscopy

In this study, the 2-mercaptopyridine (2-MPY) and 4-mercaptopyridine (4-MPY) on to silver mirror and silver sol substrates have been studied by surface enhanced Raman scattering (SERS). The surface enhanced properties of 2-MPY and 4-MPY showed that the substrate of silver mirror was superior to the sliver sol. The silver mirror and silver sol substrates were prepared by Tollenʹs and gamma irradiation method respectively. UV-visible spectra indicate that Ag nanoparticles were produced by this method. Considerable differences were found in the SERS spectra of 2-MPY and 4-MPY molecules onto silver mirror and silver sol substrates. From the analysis of the SERS data, it was evidenced that 2-MPY was chemisorbed through its S atom to Ag surfaces at a perpendicular orientation, whereas 4-MPY was bonded to Ag surface via the S atom and N atom assuming a tilted orientation.