催化学报

催化学报 ›› 2011, Vol. 32 ›› Issue (8): 1323-1328.DOI: 10.1016/S1872-2067(10)60247-1

• 研究论文 • 上一篇    下一篇

CeO2 助 Ni/MgO 催化剂用于化学气相沉积法制备多壁碳纳米管

杨文, 储伟, 江成发*, 文婕, 孙文晶   

  1. 四川大学化工学院, 四川成都 610065
  • 收稿日期:2011-03-28 修回日期:2011-04-25 出版日期:2011-08-05 发布日期:2014-12-26

Cerium Oxide Promoted Ni/MgO Catalyst for the Synthesis of Multi-walled Carbon Nanotubes

YANG Wen, CHU Wei?, JIANG Chengfa*, WEN Jie, SUN Wenjing   

  1. Department of Chemical Engineer, Sichuan University, Chengdu 610065, Sichuan, China
  • Received:2011-03-28 Revised:2011-04-25 Online:2011-08-05 Published:2014-12-26

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摘要： 以柠檬酸燃烧法制备的 Ni/MgO, Ni/CeO2-MgO 和 Ni/CeO2 为催化剂, CH4 为碳源, 采用化学气相沉积法制备多壁碳纳米管 (MWCNTs), 通过 N2 吸附、X 射线衍射、H2 程序升温还原和 X 射线光电子能谱对催化剂进行表征, 并运用热重和透射电镜表征了碳纳米管的质量和形貌. 结果表明, CeO2 的加入可有效地降低还原温度和增加易还原 Ni 物种的含量, 并使电子发生转移, 还原后的 Ni/CeO2-MgO 催化剂中, Ni 晶粒尺寸较小. 这表明 CeO2 的加入使得 Ni 物种的化学环境发生改变, 导致它和载体间的相互作用减弱, 从而促进 Ni 物种的还原, 且还原后, 高度分散在 CeO2-MgO 载体上, 从而催化剂的催化活性增加. 相比 Ni/MgO 催化剂, Ni/CeO2-MgO 为催化剂上生长的 CNTs 质量更高. 另外, 由 CeO2 助 Ni/MgO 催化剂制备出基本没有无定形碳、结晶度好的碳纳米管.

关键词: 镍, 氧化镁, 二氧化铈, 化学气相沉积法, 碳纳米管, 甲烷裂解

Abstract: Ni/MgO, Ni/CeO2-MgO, and Ni/CeO2 catalysts were prepared by the citric acid combustion method. Their catalytic properties for the synthesis of multi-walled carbon nanotubes (MWCNTs) by chemical vapor deposition using CH4 as carbon source were evaluated. The catalysts were characterized with N2 adsorption, X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The quality and structure of the CNTs were characterized by thermogravimetry (TG) and transmission electron microscopy (TEM). H2-TPR showed that CeO2 helped decrease the reduction temperature and increase the content of an easily reducible Ni species. XPS showed an energy shift of the Ni catalyst that was modified by CeO2. XRD showed that the reduced nickel maintained their small particle sizes in the Ni/CeO2-MgO catalysts. These findings suggested that the addition of CeO2 changed the chemical environment of the nickel species, which resulted in a weaker interaction between the nickel and the support and increased the reducibility of the Ni species. Moreover, the reduced nickel was highly dispersed on the CeO2-MgO support. The change enhanced the catalytic activity for the growth of carbon nanotubes (CNTs). Characterization by TG and TEM showed that the quality of the CNTs grown on Ni/CeO2-MgO was better than those grown on Ni/MgO catalyst.

Key words: nickel, magnesium oxide, cerium oxide, chemical vapor deposition method, carbon nanotubes, methane decomposition