Preparation, characterization, and Surface-Enhanced Raman Spectroscopy activity of Spherical α-Fe2O3/Ag core/shell Nanoparticles

Spherical alpha-Fe(2)O(3)/Ag core/shell nanoparticles were prepared by reducing Ag(NH(3))(2)(+) with formaldehyde using the seeding method. 3- Aminopropyltriethoxysilane (APS) acts as a "bridge" to link between alpha-Fe(2)O(3) core and Ag shell. The obtained nanoparticles were characterized by XRD, TEM, SEM, EDS, and Roman. The results show that alpha-Fe(2)O(3) cores are coated by Ag shell completely. The average size of alpha-Fe(2)O(3)/Ag nanoparticles is 95 nm and the thicknesses of Ag shell are 15nm in 3.7% HCHO and 1.0M AgNO(3). The thickness of Ag shell can be tunable by changing reaction conditions, such as the concentration of AgNO(3), reduction reaction rate. The surface-enhanced Raman scattering (SERS) effect of the core/shell particles are measured with Pyridine (Py) as molecule probe. SERS indicate that the Raman signals of Py adsorbed on alpha-Fe(2)O(3)/Ag nanoparticles exhibit large enhancement at 1010 and 1038 cm(-1) respectively. And the intensity of signals is enhanced with the increase of the thickness of Ag shell. The uniform and rough surface of alpha-Fe(2)O(3)/Ag particles exhibits strong SERS activity in 3.7% HCHO and 1.0M AgNO(3). The spherical alpha-Fe(2)O(3)/Ag core/shell nanoparticles exhibit SERS activity.