在 Fe3 O4存在下，以聚乙烯吡咯烷酮（ PVP）为分散剂和还原剂，利用简单的一步法制备了 Fe3 O4＠SiO2／Ag纳米复合材料。所制得的 Fe3 O4＠SiO2／Ag纳米复合物对罗丹明B（ RhB）具有较好的表面拉曼光谱增强（ SERS）效果，可以用作SERS基底。二氧化硅作为贵金属Ag纳米颗粒的载体，不仅可以起到分散贵金属的作用，还可以稳定金属相，更好地吸附RhB，使SERS效应得以稳定，可用于痕量检测，其检测极限可达1×10－12 mol／L。此外，该材料具有较好的磁性，方便回收再利用。该复合材料制备方法简便易行、条件温和，为合成其他纳米复合材料提供了启示。%By using PVP as the dispersant and reducing agent, Fe3 O4@SiO2/Ag nanocomposites are synthesized via a simple and one-step method in the present of Fe3 O4 .The nanocomposites are acted well as a SERS-active substrates for RhB.The SiO2 shell between Fe3 O4 nanoparticles and Ag nanoparticles is used to avoid the agglomeration of Ag nanoparticles and stabilize metal phase.The unique Raman enhancement effect of Fe3 O4@SiO2/Ag substrates indicates that RhB can be detected at a concentra-tion as low as 1 ×10 -12 M.Furthermore, the super paramagnetic property of Fe3O4 facilitates the efficient recycling of products with the assistance of an external magnetic field .This synthetic method provides a revelation for the preparation of other nanocom-posites.
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