Effect of oxidation and heat treatment on the morphology and electronic structure of carbon-encapsulated iron carbide nanoparticles
Effect of oxidation and heat treatment on the morphology and electronic structure of carbon-encapsulated iron carbide nanoparticles
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DOI：
10.1016/j.matchemphys.2012.04.063
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发表时间：
2012-07-16
影响因子：
4.6
通讯作者：
Chen, Xiaohong
中科院分区：
文献类型：
--
作者：
Fedoseeva, Yu. V.;Bulusheva, L. G.;Chen, Xiaohong
以芳香族重油和二茂铁为原料，在450℃下自压共碳化制备了碳包覆的碳化铁纳米颗粒。利用透射电子显微镜观察了空气氧化和随后在氮气气氛中热处理引起的纳米颗粒形貌和电子结构的变化。x射线衍射、近边x射线吸收精细结构光谱学和x射线发射光谱学。研究发现，将初始产物在280℃下热空气氧化5 h，得到了由氧化铁和氧化碳组成的中空纳米颗粒。将产物轻度氧化（250℃，3 h），然后在500 ~ 550℃下碳化，得到了含有氧化铁和缺陷石墨样碳的中空纳米颗粒。在1000℃下进一步退火纳米颗粒，产生具有高度石墨化碳壁的碳纳米胶囊，并部分填充球形碳化铁纳米颗粒。(C) 2012 Elsevier B.V.版权所有
Carbon-encapsulated iron carbide nanoparticles have been produced by co-carbonization of a mixture of an aromatic heavy oil and ferrocene at 450 degrees C under autogenous pressure. Transformations of the morphology and electronic structure of nanoparticles induced by air oxidation and subsequent heat treatment in a nitrogen atmosphere were examined using transmission electron microscopy. X-ray diffraction, near edge X-ray absorption fine structure spectroscopy, and X-ray emission spectroscopy. It was found that hollow nanoparticles, composed of iron oxides and oxidized carbon, were developed with thermal air oxidation of the initial product at 280 degrees C for 5 h. The mild oxidation of the product (250 degrees C for 3 h) followed by the carbonization at 500-550 degrees C yielded the hollow nanoparticles containing iron carbide/oxides and defective graphite-like carbon. The further annealing of nanoparticles at 1000 degrees C produced carbon nanocapsules with highly graphitized carbon walls and partially filled by spherical iron carbide nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.