In this work, thermal stabilities of electrochemically prepared surface-enhanced Raman scattering (SERS)-active gold and silver substrates were first investigated. The results indicate that the SERS enhancement capabilities of gold and silver substrates are seriously destroyed at temperatures higher than 200 and 125 °C, respectively. Further experiments reveal that the decrease in SERS enhancement capability mainly comes from the decrease of the chemical (CHEM) enhancement for gold substrates. However, the decrease in SERS enhancement capability can be ascribed to the decreases of both the electromagnetic (EM) enhancement and the chemical (CHEM) enhancement for silver substrates.

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 SiO(2) 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/SiO(2) nanocomposites (NCs) with an enhancement factor of 5.4 × 10(8). Experimental results indicate that pH value of solution and addition of SiO(2) 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/SiO(2) 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.

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In this work, surface-enhanced Raman scattering (SERS)-active silver substrates were prepared by electrochemical methods via oxidation-reduction cycles. These SERS-active substrates were further modified with different contents of SiO 2 nanoparticles to improve their corresponding SERS performances. With the modified substrate prepared in a 0.1 mM SiO 2 solution, the SERS of Rhodamine 6G (R6G) exhibits a higher intensity by a 3-fold order of magnitude as compared with that of R6G adsorbed on a SERS-active Ag substrate without the incorporation of SiO 2 nanoparticles. Moreover, the modified substrate prepared in a 1 mM SiO 2 solution can improve the thermal stability of the SERS-active Ag substrate. The operation temperature of the modified Ag substrate can be raised by 50 °C. The aging SERS intensity is also depressed on this modified Ag substrate due to the contribution of SiO 2 nanoparticles to SERS effects.