Department of Chemistry, University of Memphis, 3774 Walker Ave., Memphis, TN 38152, USA.
Spectrochim Acta A Mol Biomol Spectrosc. 2010 Sep 1;76(5):484-9. doi: 10.1016/j.saa.2010.04.004. Epub 2010 Apr 24.
Iron oxide magnetic nano-particles have been prepared by precipitation in an aqueous solution of iron(II) and iron(III) chlorides under basic condition. Surface modifications have been carried out by using tetraethoxysilane (TEOS) and mercaptopropyltrimethoxysilane (MPTMS). The uncoated and coated particles have been characterized with transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, thermal gravimetric analysis (TGA), and infrared (IR) and Raman spectroscopy. The particle sizes as measured from TEM images were found to have mean diameters of 13nm for the uncoated and about 19nm for the coated particles. The measured IR spectra of the uncoated and MPTMS coated particles showed the conversion of magnetite to hematite at high temperature. The results obtained from both IR spectroscopy and TGA revealed that the mercaptopropylsilyl group in the MPTMS coated magnetite decomposed at 600 degrees C and the silica layer of the TEOS coated magnetite was rather stable. Raman spectroscopy has shown the laser heating effect through the conversion of magnetite to maghemite and hematite.
通过在碱性条件下的二价和三价氯化铁的水溶液中沉淀制备了氧化铁磁性纳米粒子。通过使用四乙氧基硅烷（TEOS）和巯丙基三甲氧基硅烷（MPTMS）进行了表面改性。使用透射电子显微镜（TEM）、能量色散 X 射线（EDX）光谱、热重分析（TGA）以及红外（IR）和拉曼光谱对未涂层和涂层的颗粒进行了表征。从 TEM 图像测量的粒径发现，未涂层的平均粒径为 13nm，而涂层的粒径约为 19nm。未涂层和 MPTMS 涂层颗粒的测量红外光谱显示在高温下磁铁矿转化为赤铁矿。IR 光谱和 TGA 的结果都表明，MPTMS 涂层磁铁矿中的巯丙基硅烷在 600°C 时分解，而 TEOS 涂层磁铁矿的二氧化硅层相当稳定。拉曼光谱通过磁铁矿向磁赤铁矿和赤铁矿的转化显示出激光加热效应。
