In Situ Raman Monitoring of the Formation and Growth of Carbon Nanotubes via Chemical Vapor Deposition
In Situ Raman Monitoring of the Formation and Growth of Carbon Nanotubes via Chemical Vapor Deposition
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DOI：
10.1016/j.proeng.2015.01.126
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Karla Reinhold-López;A. Braeuer;Bettina Romann;N. Popovska-Leipertz;A. Leipertz
中科院分区：
文献类型：
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作者：
Karla Reinhold-López;A. Braeuer;Bettina Romann;N. Popovska-Leipertz;A. Leipertz
为了在催化化学气相沉积（CCVD）冷壁反应器中同时监测碳纳米管（CNT）形成和生长过程中固相和气相的相关参数，建立了基于拉曼光谱的碳纳米管状态测量技术。采用纳米铁作为催化剂，乙炔作为碳源。这项新开发的技术使沉积CNTs的气相组成、气相温度和微观结构的同时现场测量成为可能，从而最终可以跟踪碳源的分解及其对气体温度和CNTs形成和生长的影响，并将其作为反应时间的函数。我们进行了全面的定性和定量分析，以评估催化剂在生长碳纳米结构方面的性能。通过碳材料的特征D和G拉曼波段监测碳纳米管生长的时间范围和沉积结束的时间范围，并在此基础上实时监测新兴固相、成核时刻或第一信号检测。定性地提供了催化活性的信息，估计的原位d /G比揭示了生长的纳米结构的缺陷和无序含量。用于气相分析的拉曼光谱装置具有较高的检测灵敏度以及较高的准确度和精密度。催化剂活性、乙炔转化率与所得碳纳米管的微观结构之间存在相关性。
Anin situmeasurement technique based on Raman spectroscopy is established to simultaneously monitor the parameters of interest of the solid and gas phases during the formation and growth of carbon nanotubes (CNT) in a cold wall reactor for catalytic chemical vapor deposition (CCVD). Iron nanoparticles were used as a catalyst and acetylene as a carbon source. This new developed technique makes possible the simultaneousin situmeasurement of the gas phase composition, the gas phase temperature and the micro structure of the deposited CNTs, such that finally the decomposition of the carbon source and its effect on the gas temperature and on the CNTs formation and growth can be followed as a function of the reaction time. Comprehensive qualitative and quantitative analyses have been performed to assess the catalyst performance with respect to the growing carbon nanostructures. On the basis of the real-timein situRaman spectra of the emerging solid phase, the moment of nucleation or first signal detection, the time-range of the CNT growth and the end of the deposition is monitored via the characteristic D and G Raman bands for carbon materials. Information about catalytic activity is qualitatively provided and the estimatedin situD/G ratio reveals the defect and disorder content of the growing nanostructures. The Raman spectroscopy setup for the gas phase analysis exhibits high detection sensitivity as well as high accuracy and precision. Correlation could be found between the catalyst activity, acetylene conversion and micro structure of the resulting CNTs.