Effect of TiO2 nanoparticles on the improved surface-enhanced raman scattering of polypyrrole deposited on roughened gold substrates

We report here the first electrochemical oxidation-reduction cycle procedure to roughen gold substrates in 0.1 N HCl aqueous solution containing 1 mM rutile TiO₂ nanoparticles under the irradiation of UV light. It is encouraging to find that the oxidized peak in the anodic scan, which is responsible for the surface-enhanced Raman scattering, increases significantly due to the effect of adding TiO₂ under an electric field and UV irradiation. Moreover, the SERS spectrum of polypyrrole electrodeposited on the corresponding roughened gold substrate exhibits a 5-fold higher intensity compared to that without the contribution of TiO₂ nanoparticles.