Fabrication Of Au/Ag Core-shell Nanoflower As SERS Substrates And Its Application In H₂O₂ Detection

Precious metal nanoparticles such as gold, silver and platinum exhibit Localized Surface Plasmon Resonance(LSPR) upon interaction with incident light. Following this interaction, strong electromagnetic fields appeared on the surface of nanoparticles. When prepared molecules were placed on these electromagnetic fields for testing, the optical phenomena, such as Raman scattering of molecules were enhanced. This amplification of optical signals made precious metal nanoparticles act as Surface Enhanced Raman Scattering(SERS) substrates which are now widely used for substance detection.“Hot spots”, the area in which electromagnetic fields are highly magnified, have attracted lots of interests in the fields of SERS. In this paper, colloidal Ag/Au nanoflower fabrication was performed and MES was added to the colloid for stable aggregation. 4-MBA acted as Raman probe molecules to demonstrate compatibility between “hot spots” and SERS. The results showed that “hot spots” actually played a significant role in SERS and showed that the enhancement factor of Ag/Au nanoflower substrates could be up to 106.Furthermore, these creative SERS substrates were applied to detect hydrogen peroxide, the oxidizability of hydrogen peroxide can be used to change the element silver into an ionized state. This oxidation results in sharply decreased SERS’ ability. The standard curve of hydrogen peroxide detection was based on the change of 4-MBA‘s Raman signal intensity, determined by the concentration of hydrogen peroxide. The sensitive detection range of this novel sensor was between 10-6 M and 10-3 M, and the lowest detection limitation reached up to 10-7 M. This highperformance hydrogen peroxide sensor achieved ultra-sensitive detection with low cost and celerity. Therefore, the above advantage of the Ag/Au nanoflower substrate is expected to be widely utilized to detect hydrogen peroxide in food.