TIME-RESOLVED SURFACE-ENHANCED RAMAN-SPECTROSCOPIC STUDIES ON COADSORPTION OF DERIVATIVES OF THIOUREA WITH CLO4- AT AG ELECTRODES

By means of Surface-enhanced Raman Spectroscopy (SERS),Time-resolved S urface-enhanced Raman Spectroscopy (TRSERS) and potential step method, the coadsorption behavior of methyl thiourea (MTU) and 1-allyl-2-thio urea (ATU) with ClO4- respectively at Ag electrodes has been studied. The SERS intensity-time profiles show that the intensities of differen t SERS bands have surprisingly different response rates to the potenti al step. The response rates of the groups of the adsorbed species whic h is close to the electrode surface are fast. The results also indicat e that MTU is vertically adsorbed on Ag electrode surface via S atom,w hile ATU is adsorbed on the surface via S atom and the molecules leane d to the electrode surface.