Substrate-Immersed Solvothermal Synthesis of Ordered SiO2/Ag Arrays as Catalytic SERS Substrates

In this work, we designed a simple substrate-immersed solvothermal route for the one-step synthesis of novel ordered SiO 2 /Ag arrays, employing SiO 2 colloidal crystals as templates and alcohol as reducing agent. The Ag nanoparticles were uniformly deposited in situ onto SiO 2 colloidal crystals, which exhibited high surface enhanced Raman spectroscopy (SERS) activity and uniform SERS intensity. It was found that ordered SiO 2 /Ag arrays could rapidly scavenge the absorbed-Nile blue A (NBA) molecules from the surfaces with the assistance of H 2 O 2 , while the SERS signals of NBA decreased sharply and almost completely disappeared within four minutes. This can be attributed to the superior catalytic activity of Ag nanoparticles. After five times of re-immersion and re-absorbing process of NBA, the substrates could still keep ∼ 74.8% SERS intensity versus the original. The high activity and durability of the as-prepared SiO 2 /Ag SERS substrate endow them as a promising candidate for trace detection.