Multiwall carbon nanotubes continuously filled with micrometre-length ferromagnetic α-Fe nanowires
Multiwall carbon nanotubes continuously filled with micrometre-length ferromagnetic α-Fe nanowires
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DOI：
10.1016/j.carbon.2013.07.085
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发表时间：
2013-11
期刊：
影响因子：
10.9
通讯作者：
F. Boi;G. Mountjoy;R. Wilson;Z. Luklinska;Laura J. Sawiak;M. Baxendale
中科院分区：
文献类型：
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作者：
F. Boi;G. Mountjoy;R. Wilson;Z. Luklinska;Laura J. Sawiak;M. Baxendale
采用一种新的化学气相沉积法制备了纳米尺度和微米尺度的铁磁相α-Fe纳米线填充碳纳米管。我们报道了一种新的两阶段方法，一种扰动蒸汽合成方法，然后进行合成后热处理，产生填充有至少19微米长的α-Fe纳米线的多壁碳纳米管。先前报道的合成路线使用稳态条件来保证纳米线连续性，但仅产生包含α-Fe、Fe 3C或γ-Fe的隔离相或混合相的小（小于一微米长度）纳米线。在常规的水平化学气相沉积反应器中，通过扰动二茂铁（Fe（C5 H5）2）层流蒸汽流，制备了连续填充α-Fe的花状碳纳米管簇。单相填充通过在Ar流中在500 °C下合成后退火15小时来实现。电子显微镜的研究表明，高品质的纳米管和封装的纳米线的结构完整性。这些纳米结构具有580 Oe的高磁化率和189.5 emu/g的非常高的饱和磁化强度，与体α-Fe相当。
Carbon nanotubes filled with continuous crystalline nanowires of nanometre-scale diameter and micrometre-scale length of the ferromagnetic phase α-Fe were produced with a new chemical vapour deposition method. We report a new two-stage approach, a perturbed-vapour method of synthesis followed by a post-synthesis heat treatment that produces multiwall carbon nanotubes filled with at least 19 micrometre-length nanowires of α-Fe. Previously reported synthesis routes use steady-state conditions to guarantee nanowire continuity but result only in small (less than one-micrometre length) nanowires comprising isolated or mixed phases of either α-Fe, Fe3C, or γ-Fe. Here flower-like clusters of carbon nanotubes continuously filled with α-Fe were produced by perturbation of a laminar ferrocene (Fe(C5H5)2) vapour flow in a conventional horizontal chemical vapour deposition reactor. Single-phase filling was achieved by a post-synthesis annealing at 500 °C for 15 h in Ar flow. Electron microscopy studies revealed the high quality of the structural integrity of both nanotubes and encapsulated nanowires. These nanostructures possess a high coercivity of 580 Oe and a very high saturation magnetization of 189.5 emu/g comparable with bulk α-Fe.