[Electrochemical character of gold/silver nanoparticles and SERS studies on benzidine]

Colloidal gold was prepared by sodium citrate-induced reduction of hydrogen tetrachloroaurate. Colloidal silver was prepared by the reduction of silver nitrate by sodium borohydride respectively. The gold and silver sols were characterized by means of UV-Vis, SEM and CVs. Results show that the gold and silver colloids were a monodisperse suspension with the average size of 16 and 10 nm respectively; Ordered sub-monolayer structure of gold and silver nanoparticles on the ITO was fabricated by self-assembly technique. The CV character of gold and silver nanoparticles features a pair of asymmetrical ox-red peaks separately, moreover, the positions of these peaks are influenced by the concentrations of gold and silver nanoparticles. Ordered double-layer structures of gold/silver nanoparticles on roughened gold substrates were obtained by self-assembly method, where benzidine was used as the coupling molecules. The results of surface-enhanced Raman spectroscopic characterization show that Raman scattering of benzidine molecules during self-assembly is enhanced.