Zinc Ferrite Nanoparticles via Coprecipitation Modified Method: Glycerol as Structure Directing and Stabilizing Agent

Coprecipitation is one of the most practical methods used to synthesize ferrite nanoparticles. Fine characteristics of these materials can be improved by means of a series of modifications in the synthesis method. In this paper we present a study of influence of glycerol as structure directing and stabilizing agent in the synthesis of zinc ferrite nanoparticle, exploring its chelating capacity and oxidation. The studied materials include two series of zinc ferrite samples and its precursors obtained with or without glycerol throughout different stages during the synthesis process. The structural and morphological characteristics were evaluated by means of different techniques such as X-ray diffraction, Fourier transformed infrared spectroscopy, scanning and transmission electron microscopy and thermal analysis. The oxidation of glycerol was determined by high-performance liquid chromatograph. The obtained results demonstrate that zinc ferrite crystals synthesized in the presence of glycerol are initially bigger than those synthesized in absence of it, but according to the oxidation process they tend to decrease giving rise to intermediate phases. Interestingly, these samples grow back during more advanced stages and become structurally better organized, compared to the series of samples produced in absence of glycerol. These results indicate that glycerol is capable to modify the synthesis route of zinc ferrite nanoparticles via coprecipitation, acting directly over the size and morphology of the crystals.

共沉淀法是合成铁氧体纳米颗粒（ferrite nanoparticles）的主流实用方法之一。通过对合成工艺开展一系列改性优化，可有效改善这类材料的精细性能。本文以甘油（glycerol）作为结构导向剂与稳定剂，研究其在锌铁氧体纳米颗粒（zinc ferrite nanoparticle）合成过程中的调控作用，并探讨了甘油的螯合能力与氧化特性。本研究制备了两组锌铁氧体样品及其前驱体，两组样品分别在合成过程的不同阶段添加或不添加甘油。采用多种表征技术对所得材料的结构与形貌特征进行表征，涵盖X射线衍射（X-ray diffraction）、傅里叶变换红外光谱（Fourier transformed infrared spectroscopy）、扫描与透射电子显微镜（scanning and transmission electron microscopy）以及热分析（thermal analysis）；同时通过高效液相色谱仪（high-performance liquid chromatograph）测定了甘油的氧化反应进程。研究结果显示，添加甘油合成的锌铁氧体晶体初始尺寸大于未添加甘油的对照组样品，但随着氧化过程的推进，此类晶体尺寸会逐渐减小并生成中间相。值得注意的是，与未添加甘油制备的样品组相比，经后续更高级反应阶段后，添加甘油的样品晶体尺寸会再次增大，且结构有序性更为优异。上述结果证实，甘油可通过共沉淀法调控锌铁氧体纳米颗粒的合成路径，直接作用于晶体的尺寸与形貌。