Abstract In this study, the gaseous and condensate products of ethanol decomposition during the synthesis of single-walled carbon nanotubes (SWCNTs) by aerosol chemical vapor deposition (floating catalyst CVD) method were investigated. To determine the conditions for perfect and clean SWCNT formation the products synthesized at different temperatures and collected inside and outside the reactor were studied by transmission electron microscopy, Raman, Fourier transform infrared (FT-IR) and optical absorption spectroscopy. The individual and bundled SWCNTs of a predominantly small diameter (∼1 nm) were revealed. The obtained tubes exhibit a stable distribution of chiral indices in a wide range of the set temperature (750–1000 °C), which is promising for the development of controlled synthesis methods. The FT-IR analysis results show that the main gaseous products of thermal ethanol decomposition in our CVD system are methane and carbon monoxide. Acting as carbon source, the mixture of CO and CH4 makes possible to produce pure SWCNTs, as those obtained in the catalytic CO disproportionation method, with higher yield, taking into account twice the amount of carbon release during CH4 catalytic pyrolysis. The carbon deposit on the reactor wall is found to play important role in maintaining an optimal regime of CNT synthesis.

中文翻译：

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乙醇分解的气体和冷凝产物对气溶胶 CVD 合成单壁碳纳米管的影响

摘要 在本研究中，研究了气溶胶化学气相沉积（浮动催化剂 CVD）法合成单壁碳纳米管（SWCNT）过程中乙醇分解的气态和冷凝产物。为了确定完美和清洁 SWCNT 形成的条件，通过透射电子显微镜、拉曼、傅里叶变换红外 (FT-IR) 和光学吸收光谱研究了在不同温度下合成并在反应器内外收集的产物。揭示了主要是小直径（~1 nm）的单个和成束的 SWCNT。所获得的管在设定温度（750-1000°C）的很宽范围内表现出稳定的手性指数分布，这对于控制合成方法的发展是有希望的。FT-IR 分析结果表明，我们的 CVD 系统中乙醇热分解的主要气态产物是甲烷和一氧化碳。作为碳源，CO 和 CH4 的混合物可以生产纯 SWCNT，正如在催化 CO 歧化方法中获得的那样，考虑到 CH4 催化热解过程中释放的碳量是原来的两倍，产量更高。发现反应器壁上的碳沉积物在维持碳纳米管合成的最佳状态方面起着重要作用。考虑到 CH4 催化热解过程中碳释放量的两倍。发现反应器壁上的碳沉积物在维持碳纳米管合成的最佳状态方面起着重要作用。考虑到 CH4 催化热解过程中碳释放量的两倍。发现反应器壁上的碳沉积物在维持碳纳米管合成的最佳状态方面起着重要作用。