用3A分子筛作模板构建灵敏的表面增强拉曼光谱银基底

Construction of a sensitive silver substrate for surface-enhanced Raman scattering spectroscopy by using 3A molecular sieves as templates

成功地制备了一种灵敏的表面增强拉曼散射（SERS）银基底。即以3A分子筛为模板，以葡萄糖为还原剂，通过改善的银镜反应在分子筛上建构银壳，再用稀氢氟酸去掉分子筛核制备中带有平的内表面的平板堆砌而成的聚集体。通过扫描电子显微镜观测了其大小和形貌，通过X-射线粉末衍射仪研究了其结构。以4-羟基苯硫酚（4-MPH）为探针分子，考察了其SERS活性，与在玻璃基底上构建的银纳米粒子和商品微米银粉末相比，吸附在该平板银聚集体上的4-MPH在～1078cm^-1处谱带的SERS峰强度是吸附在以玻璃为基底的银纳米粒子的40倍左右，是吸附在商品微米银粉未的13倍左右。通过计算，该SERS活性基底的增强因子约为2.8×10^5。这种灵敏的SERS基底容易制备，成本合适，在设计、开发SERS光谱探针装置等方面有很好的应用前景。

A sensitive silver substrate has been successfully fabricated for surface-enhanced Raman scattering （SERS） spectroscopy. 3A molecular sieves covered with silver shells were prepared by using a modified silver mirror reaction. Here, the process was performed by using 3A molecular sieves as templates and glucose as reductive agent. By subsequent treatment with dilute hydrofluoric acid,3A molecular sieve cores were removed to produce the planar silver aggregations. The size and morphologies of the planar silver aggregations were studied by means of scanning electron microscopy, and its structures were monitored through X-ray powder diffractometer. The SERS activity of the product was examined using 4-Mercaptophenol （4-MPH） as probing adsorbate;its SERS activity was compared with those of the silver nanoparticles coated on a glass substrate and the commercially available 2 μm-sized silver（μAg） powders. It has prominent advantages that the SERS peak intensity of the ～1078 cm^-1 band of 4- MPH adsorbed on the planar silver aggregations is about 40 and 13 times greater than when it is adsorbed on the silver nanoparticles coated on a glass substrate or on the μAg powders, respectively. The enhancement factor of the planar silver aggregations was estimated to be ～2. 8×10^5. The sensitive SERS-active substrate is produced simply and cost-effectively, so it is expected to play a great role in the development of SERS-based analytical devices.