关键词: 碳纳米管, La-Ni-O, 催化剂前驱体

Abstract: A series of La-Ni-O compounds were synthesized with modifying the mol ratio of La to Ni by citric acid complexometry and used as the catalyst precursors to prepare carbon nanotubes (CNT) by the chemical vapor deposition method (CVD). At the same time, H₂, N₂ and C₂H₂ were used as the reduction gas, protection gas and carbon source gas, respectively. The structures of the catalyst precursors before and after reducing by H₂ were characterized by XRD and the patterns of the CNT obtained from the catalyst precursors were characterized by TEM. The results show that only chemical compounds LaNiO₃ and La₂NiO₄ in the series La-Ni-O catalyst precursors have the ability to prepare CNT. However, the yield of CNT from the catalyst precursor LaNiO₃ is greatly higher than that from the catalyst precursor La₂NiO₄. And the reason is that the content of nano-meter metal Ni (111) crystal face in the productions from LaNiO₃ after being reduced is higher than that from La₂NiO₄. That is to say the higher the content of nano-meter metal Ni (111) crystal face and the larger the grain size, the higher the yield of CNT and the larger the inner diameter of CNT.

Key words: carbon nanotubes, La-Ni-O, catalyst precursor