Surface-enhanced Raman scattering-active Au/TiO2 films prepared by electrochemical and photochemical methods

In this work, we report a new strategy for the preparation of surface-enhanced Raman scattering (SERS)-active Au/TiO2(P25) nanocomposites (NCs), using electrochemical and photochemical methods. First, Au substrates were subjected to electrochemical oxidation–reduction cycles (ORCs) in a deoxygenated aqueous solution containing 0.1 M HCl and 1 mM TiO2. After the ORC treatment AuCl4−-adsorbed TiO2 complexes were produced in the solution. These complex-containing substrates were then irradiated with UV light at 310 nm to synthesize Au/TiO2 NCs with strong SERS activities for probe molecules of rhodamine 6G (R6G) and conductive polymers of polypyrrole (PPy). Experimental results indicated that the wavelength of UV light and the presence of TiO2 before and after the ORC procedure during the preparation process both affected the resulting SERS activities.