Effect of the La-Ni-O Catalyst Precursor on Carbon Nanotubes Growth
催化剂前驱体对碳纳米管生长影响的研究

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,H_2,N_2 and C_2H_2 were used as the reduction gas,protection gas and carbon source gas,respectively.The structures of the catalyst precursors before and after reducing by H_2 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 LaNiO_3 and La_2NiO_4 in the series La-Ni-O catalyst precursors have the ability to prepare CNT.However,the yield of CNT from the catalyst precursor LaNiO_3 is greatly higher than that from the catalyst precursor La_2NiO_4.And the reason is that the content of nano-meter metal Ni(111) crystal face in the productions from LaNiO_3 after being reduced is higher than that from La_2NiO_4.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.