Mechanisms of titania nanoparticle mediated growth of turbostratic carbon nanotubes and nanofibers
Mechanisms of titania nanoparticle mediated growth of turbostratic carbon nanotubes and nanofibers
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DOI：
10.17863/cam.12220
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发表时间：
2017-07
影响因子：
3.2
通讯作者：
A. Kudō;S. Steiner;B. Bayer;P. Kidambi;S. Hofmann;M. Strano;B. Wardle
中科院分区：
文献类型：
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作者：
A. Kudō;S. Steiner;B. Bayer;P. Kidambi;S. Hofmann;M. Strano;B. Wardle
采用化学气相沉积法，以二氧化钛纳米颗粒为催化剂，合成了乱层结构的碳纳米管（CNTs）和纳米纤维（CNFs），并建立了一个定量的剥离模型来解释CNTs和CNFs的生长。以乙炔为碳原料，采用氧化铝为载体，制备了大尺度的长乱层碳纳米管和碳纳米纤维，提高了催化剂分布的均匀性。在不存在通常在金属纳米颗粒介导的生长中观察到的石墨笼的情况下，总是发现乱层CNT/CNF附着于纳米颗粒角落。在乱层碳纳米管/碳纳米纤维中观察到的形态支持一种模型，其中几层石墨烯从二氧化钛纳米颗粒催化剂的高曲率角部剥离。该模型解释了一个关键特征，该特征将通过非金属纳米颗粒的乱层CNT/CNF的生长与使用标准金属纳米颗粒催化剂的生长区分开来。所观察到的CNT/CNF生长和伴随的模型可以影响其他金属氧化物纳米颗粒催化剂的评估，这里的发现有助于无金属合成乱层CNT/CNF。
Turbostratic carbon nanotubes (CNTs) and nanofibers (CNFs) are synthesized by chemical vapor deposition using titania nanoparticle catalysts, and a quantitative lift-off model is developed to explain CNT and CNF growth. Micron-scale long turbostratic CNTs and CNFs were observed when acetylene is utilized as a carbon feedstock, and an alumina substrate was incorporated to improve the homogeneity of catalyst distribution. Turbostratic CNTs/CNFs are always found attached to nanoparticle corners, in the absence of the graphitic cage that is typically observed with metal nanoparticle-mediated growth. The observed morphology in turbostratic CNTs/CNFs supports a model in which several layers of graphene lift off from high-curvature corners of the titania nanoparticle catalysts. This model explains a key feature, which differentiates the growth of turbostratic CNTs/CNFs via non-metallic nanoparticles from growth using standard metal nanoparticle catalysts. The observed CNT/CNF growth and the accompanying model can impact the assessment of other metal-oxide nanoparticle catalysts, with the findings here contributing to a metal-free synthesis of turbostratic CNTs/CNFs.