New pathway to prepare surface-enhanced Raman scattering-active Au/TiO 2 nanocomposites-containing substrates by sonoelectrochemical methods

Many methods have been reported in the literature to improve signals and stabilities of surface-enhanced Raman scattering (SERS) for their reliable applications. In this work, we propose a new pathway to prepare SERS-active substrates with Au/TiO₂ nanocomposites (NCs) by electrochemical methods to achieve these goals. First, Au substrate was treated by electrochemical oxidation-reduction cycles (ORCs) in a solution containing 0.1 M HCl and 1 mM TiO₂ nanoparticles (NPs). Subsequently, the Au substrate was immediately replaced by Pt substrate, and a cathodic overpotential of 0.6 V was applied under sonication to prepare SERS-active Au/TiO₂ NCs on the Pt substrate. Experimental results indicate that the SERS enhancement capability of the Au/TiO₂ NCs-deposited Pt substrate is seriously destroyed only at temperature higher than 225 °C. Also, aging of the SERS effect in 50% RH and 20% (v/v) O₂ at 30 °C is slight based on this substrate. Conclusively, the stabilities of the developed SERS-active substrates are satisfactory.