Surface-Enhanced Raman Scattering-Active Au/SiO₂ Nanocomposites Prepared Using Sonoelectrochemical Pulse Deposition Methods

For improving signals, reproducibility, and stabilities of surface-enhanced Raman scattering (SERS), numerous technologies have recently been reported in the literature. However, the fabrication processes are usually complicated. It is well-known that nanoparticles (NPs) of Au and SiO₂ are SERS active and inactive materials, respectively. In this work, a simple synthesis route based on sonoelectrochemical pulse deposition (SEPD) methods has been developed to synthesize effectively SERS-active Au/SiO₂ nanocomposites (NCs) with an enhancement factor of 5.4 × 10⁸. Experimental results indicate that pH value of solution and addition of SiO₂ NPs before and after oxidation–reduction cycles (ORCs) can significantly influence the corresponding SERS activities. Encouragingly, the SERS of Rhodamine 6G (R6G) adsorbed on the developed Au/SiO₂ NCs exhibits a higher intensity by more than 1 order of magnitude, as compared with that of R6G adsorbed on Au NPs synthesized using the same method. Moreover, this improved SERS activity is successfully verified from the mechanisms of electromagnetic (EM) and chemical (CHEM) enhancements