Adsorption behavior of urea on silver electrode and the influence of thiourea on its adsorption in snlphuric acid solution were illvestigated by polarization curves and Surface Enhanccd Raman Spectroscopy. Urea was found to undergo a condensation reaction on roughcned silvcr electrode. Billret was the condensation compound, and was adsorbed in the protonatcd forrn on the silver surface. Obvious synergistic mechanism between thiourea and protonated biuret was proposed.
Adsorption of thiourea (TU) and ethylthiourea(ETU) on roughened silver electrode was investigated using in- situ surface enhanced Raman spectroscopy(SERS).Using quantum chemistry and HSAB theories, the influences of electrode potential and the different substituent groups on SERS were discussed. TU is chemisorbed perpendicularly by Ag-S bond on silver at E=-0.3 V and adsorption of TU turns into a parallel orientation at E=-0.9 V. ETU is always chemisorbed at an angle from Ag. The adsorption of ETU is through C=C andC=O groups at E=-0.3 V, and mainly through C=C at E=-0.9V.
