CoFe₂O₄/Ag Nanostructures as Highly Sensitive Surface-Enhanced Raman Scattering Substrates

At present, there is an urgent need to design sensitive substrates for the Raman analysis system to detect potential substances that have major ramifications for health care and the ecological environment. In this work, CoFe2O4/Ag nanostructures with two different morphologies were successfully synthesized as surface-enhanced Raman scattering (SERS) substrates. The as-prepared strawberry-like CoFe2O4@SiO2@Ag and snowman-like CoFe2O4-Ag Janus not only displayed high sensitivity due to the surface plasma resonance (SPR) of Ag nanoparticles and special micro-nano structure but also showed good stability, which was determined by Raman measurement and enhancement factor calculation. Moreover, excellent magnetic response ensured that the composites could be separated rapidly and reused effectively. It was demonstrated that the as-synthesized CoFe2O4@SiO2@Ag and CoFe2O4-Ag Janus composites had great potential as separable, reusable, and active SERS substrates.