摘要： 用金属还原菌Shewanella oneidensis MR-1在Fe₃O₄微球表面原位还原Ag⁺形成了Ag/Fe₃O₄磁性复合材料。采用HRTEM、XRD、VSM、XPS对Ag/Fe₃O₄的结构和性能进行表征。结果表明：银纳米颗粒（约15 nm）较为均匀分散在Fe₃O₄微球（约380 nm）表面；在可见光照射下，Ag/Fe₃O₄具有较高的催化活性，50 min内对亚甲基蓝的降解率可达96.3%，较未负载Ag的Fe₃O₄微球的降解率提高了20.3%。Ag/Fe₃O₄在室温下呈现超顺磁性，饱和磁强度为34.9 emu/g，在外加磁场条件下能快速从溶液中分离；且复合材料表现出较好的循环稳定性，6次循环后其催化活性无明显变化。

关键词: Ag/Fe₃O₄磁性复合材料, 还原菌, 原位还原, 光催化

Abstract: The Ag/Fe₃O₄ magnetic composite material has been formed, using metal-reduction bacteria, Shewanella oneidensis MR-1, for reducing silver ions in site on the surface of Fe₃O₄ microspheres. The structure and performance of Ag/Fe₃O₄ have been characterized by means of HRTEM, XRD, VSM, and XPS, respectively. The results show that Ag NPs (about 15 nm) are distributed pretty homogeneously on the surface of Fe₃O₄ microspheres (about 380 nm). The Ag/Fe₃O₄ composite has high photocatalytic activity under visible light irradiation, by which the degradation rate of methylene blue(MB) can reach 96.3% within 50 min, and the degradation rate is increased by 20.3%, compared to pure Fe₃O₄ microspheres. Ag/Fe₃O₄ shows super-paramagnetism at room temperature. The intensity of saturated magnetism is 34.9 emu/g,which can be separated from the solution rapidly under externally-applied magnetic field condition. In addition, the composite material shows comparatively good cyclical stability. After six times of cycling, its catalytic activity does not have any obvious changes.

Key words: Ag/Fe₃O₄ magnetic composite, reducing bacteria, in site reduction, photocatalysis

中图分类号: 

• X703