Abstract: The iron nanoparticles have been synthesized through sodium borohydride chemical solution reduction of ferric iron-impregnated montmorillonite (Mt) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer. A combination of scanning electron microscope, transmission electron microscope, X-ray diffraction, and X-ray photoemission spectroscopy was used to characterize the materials. As a result, these obtained iron particles were well dispersed on the external surface of Mt and were of roughly spherical morphology and uniform particle size with a mean diameter about 34nm. The metallic iron cores remained in these iron nanoparticles were protected from further oxidation by their native iron oxide shell with a thickness of about 3nm. Compared with the iron nanoparticles synthesized in the absence of Mt and PVP, these obtained iron nanoparticles exhibited reduced size and improved dispersity, which should be attributed to the dispersing action of the polymer stabilizer and the delaminated structure of Mt as a results of the interfacial interactions between Mt particles and PVP.

Key words: support, polymers, reduction, nanoparticles, interface, oxidation

摘要： 以蒙脱石为载体，水溶性聚合物聚乙烯吡咯烷酮（PVP）为稳定剂，通过硼氢化钠化学液相还原高铁离子制备了零价铁纳米粒子。采用扫描电镜、透射电镜、X射线衍射分析、X射线光电子能谱分析等手段对所得铁粒子进行了表征。结果表明，所得铁粒子大致呈球状形貌，尺寸较均匀，平均粒径约为34nm，在蒙脱石颗粒外表面分散良好。该铁粒子内核为零价铁，表面包覆铁氧化物外壳，外壳厚度保持3nm左右，有效抑制了零价铁内核的深度氧化。PVP自身及其与蒙脱石颗粒通过界面作用形成的层离结构均可对铁粒子起到分散作用，使所得铁粒子较之蒙脱石和PVP未参与制备的铁粒子粒径减小、分散程度提高。

关键词: 载体, 聚合物, 还原, 纳米粒子, 界面, 氧化