Stabilizing Ag Nanoparticles Using Anatase TiO2 and Cu on Al Surface

Chemical adsorption of anatase TiO2, silver nanoparticles (Ag NPs), and Cu particles (Cu Ps) on aluminum (Al) surface yielded an active surface-enhanced Raman scattering (SERS) substrate. TiO2 is known to reduce both silver (Ag) and copper (Cu). In an oxidizing environment, Ag NPs remain unoxidized since Cu has a more negative redox potential than Ag. Ag is therefore protected by Cu from getting oxidized. Although Ag NPs exhibit better SERS activity than Au NPs, Ag is relatively easier to oxidize, limiting the development of Ag-based nanomaterials. Therefore, despite the poor SERS activity of Au nanoparticles than that of Ag nanoparticles, Au nanoparticles have been widely used. Herein, the stabilization of Ag nanoparticles by incorporating a reductive process using anatase TiO2 is reported. The fabricated substrates bearing anatase, Ag NPs, and Cu Ps were stable, as seen by Raman spectra, and remained unchanged for more than 2 months.