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

Abstract

In this work, we designed a simple substrate-immersed solvothermal route for the one-step synthesis of novel ordered SiO2/Ag arrays, employing SiO2 colloidal crystals as templates and alcohol as reducing agent. The Ag nanoparticles were uniformly deposited in situ onto SiO2 colloidal crystals, which exhibited high surface enhanced Raman spectroscopy (SERS) activity and uniform SERS intensity. It was found that ordered SiO2/Ag arrays could rapidly scavenge the absorbed-Nile blue A (NBA) molecules from the surfaces with the assistance of H2O2, 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 [Formula: see text] 74.8% SERS intensity versus the original. The high activity and durability of the as-prepared SiO2/Ag SERS substrate endow them as a promising candidate for trace detection.