Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS
Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS
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DOI：
10.1039/c5ce01585e
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发表时间：
2015-01-01
期刊：
影响因子：
3.1
通讯作者：
Emmerling, Franziska
中科院分区：
文献类型：
--
作者：
Kabelitz, Anke;Guilherme, Ana;Emmerling, Franziska
氯化铁与碱性试剂的反应是合成氧化铁纳米颗粒的主要方法之一。研究了以三乙醇胺为反应物和稳定剂的颗粒形成机理。原位快速x射线吸收近边光谱和小角度x射线散射同时提供了氧化态信息和结构信息。原位数据由非原位透射电子显微镜、广角x射线散射和拉曼分析补充。研究了氯化铁和氯化亚铁形成磁赤铁矿纳米粒子（γ - fe2o3）的过程。在这些纳米颗粒形成之前，观察到中间相（赤球石，铁（II， III）氢氧化物）的形成和转化经历了形态和结构的崩溃。随着反应时间的延长，形成的小磁铁矿纳米颗粒（Fe3O4）进一步生长并转化为磁铁矿。
The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles. We studied the particle formation mechanism using triethanolamine as reactant and stabilizing agent. In situ fast-X-ray absorption near edge spectroscopy and small-angle X-ray scattering provide information on the oxidation state and the structural information at the same time. In situ data were complemented by ex situ transmission electron microscopy, wide-angle X-ray scattering and Raman analysis of the formed nanoparticles. The formation of maghemite nanoparticles (gamma-Fe2O3) from ferric and ferrous chloride was investigated. Prior to the formation of these nanoparticles, the formation and conversion of intermediate phases (akaganeite, iron(II, III) hydroxides) was observed which undergoes a morphological and structural collapse. The thus formed small magnetite nanoparticles (Fe3O4) grow further and convert to maghemite with increasing reaction time.