Yiu H H P, Keane M A, Lethbridge Z A D, Lees M R, El Haj A J, Dobson J
Department of Chemistry, University of Liverpool, Liverpool, Merseyside L69 7ZD, UK. Institute of Science and Technology in Medicine, Keele University, Thornburrow Drive, Hartshill, Stoke-on-Trent ST4 7QB, UK.
Nanotechnology. 2008 Jun 25;19(25):255606. doi: 10.1088/0957-4484/19/25/255606. Epub 2008 May 15.
Magnetic iron metal-silica and magnetite-silica nanocomposites have been prepared via temperature-programed reduction (TPR) of an iron oxide-SBA-15 (SBA: Santa Barbara Amorphous) composite. TPR of the starting SBA-15 supported Fe(2)O(3) generated Fe(3)O(4) and FeO as stepwise intermediates in the ultimate formation of Fe-SBA-15. The composite materials have been characterized by means of x-ray diffraction, high resolution transmission electron microscopy and SQUID (superconducting quantum interference device) magnetometry. The Fe oxide and metal components form a core, as nanoscale particles, that is entrapped in the SBA-15 pore network. Fe(3)O(4)-SBA-15 and Fe-SBA-15 exhibited superparamagnetic properties with a total magnetization value of 17 emu g(-1). The magnetite-silica composite (at an Fe(3)O(4) loading of 30% w/w) delivered a magnetization that exceeded values reported in the literature or obtained with commercial samples. Due to the high pore volume of the mesoporous template, the magnetite content can be increased to 83% w/w with a further enhancement of magnetization.
通过对氧化铁-SBA-15（SBA：圣巴巴拉无定形）复合材料进行程序升温还原（TPR）制备了磁性铁金属-二氧化硅和磁铁矿-二氧化硅纳米复合材料。起始的SBA-15负载的Fe(2)O(3)的TPR在最终形成Fe-SBA-15的过程中产生了Fe(3)O(4)和FeO作为逐步中间体。通过X射线衍射、高分辨率透射电子显微镜和SQUID（超导量子干涉装置）磁强计对复合材料进行了表征。Fe氧化物和金属成分形成一个核心，作为纳米级颗粒，被困在SBA-15孔网络中。Fe(3)O(4)-SBA-15和Fe-SBA-15表现出超顺磁性，总磁化值为17 emu g(-1)。磁铁矿-二氧化硅复合材料（Fe(3)O(4)负载量为30% w/w）的磁化强度超过了文献报道的值或商业样品的值。由于介孔模板的高孔体积，磁铁矿含量可增加到83% w/w，同时磁化强度进一步增强。
