α-Fe2O3/Ag核壳结构纳米复合颗粒的制备及SESR性能

摘要

With the seeding method, α-Fe2O3/Ag core-shell composite powders were prepared by the reduction of Ag [(NH3 )2 ]+ with formaldehyde as reductant, and 3-aminopropyl triethoxysilane as additive. 3-Aminopropyl triethoxysilane (APS) acted as a “bridge” to connect α-Fe2O3 and Ag particles. The obtained nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy-dispersive X-ray spectrometry (EDX). The influences of concentration of APS, volume ratio of alcohol to water on the coating effect and performance of nanoeomposites were investigated. With pyridine (Py) as a molecule probe, Raman spectroscopy (SERS)properties and stability of the α-Fe2 O3/Ag core/shell composite particles were studied. The results showed that the obtained α-Fe2O3/Ag composites were coated completely, well-dispersed and the average sizes were approximately 65 nm, when the dosage of APS was 0. 75％ (mass) and the volume ratio of alcohol to water was 5: 1. By coating Ag layer, the intensities of SERS were enhanced at 1010 cm-1 and 1038 cm-1 .Especially, the signals of Py absorbed on α-Fe2 O3/Ag substrate were greatly increased at 1038 cm-1. And this substrate was fairly stable after being placed in air for one month.%用籽晶法,以甲醛为还原剂、3-氨丙基三乙氧基硅烷(APS)为改性剂,在Ag[(NH3)2]+溶液中制备α-Fe2O3/Ag核壳结构复合粉体.采用XRD、TEM和EDX对样品进行表征,系统研究了APS改性剂、醇水比等对复合纳米颗粒包覆效果及性能的影响;并用吡啶(Py)为探针,研究了α-Fe2O3/Ag核壳纳米颗粒作为拉曼衬底时的拉曼增强性能(SERS)及稳定性.结果表明,当APS=0.75%(质量),醇水比=5:1时,α-Fe2O3/Ag核壳结构纳米颗粒的平均粒径为65 nm左右,包覆完整,分散均匀,位于1010 cm-1和1038 cm-1处吡啶信号显著增强,具有良好的SERS活性.在空气中放置一段时间后仍能保持较好的增强效果,稳定性好.