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采用柠檬酸络合法,通过改变La和Ni的摩尔比例获得了一系列的La-Ni- O催化剂前驱体,以H_2作为还原气体,N_2为保护气体,C_2H_2为碳源,采用化学气相沉积法制备碳纳米管(CNT)．用XRD研究所得催化剂前驱体还原前后的结构,TEM观察所得CNT的形貌．结果发现：在所制备的一系列La-Ni-O催化剂前驱体中,具有催化活性的物质只有：LaNiO_3和La_2NiO_4．但由LaNiO_3所制备的CNT的产率却大大高于由La_2NiO_4所制备的CNT的产率．经分析认为,这主要是与两者被还原后的产物中的纳米级金属Ni的(111)晶面含量有关,纳米级金属Ni的(111)晶面含量和晶粒度越大,其CNT的产率和内径也就越大．
A series of La-Ni-O catalyst precursors were obtained by changing the mole ratio of La to Ni by using citric acid complexation method. H_2 was used as a reducing gas, N_2 was a protective gas and C_2H_2 was a carbon source. The chemical vapor deposition Preparation of carbon nanotubes (CNTs). The structures of the obtained catalyst precursors before and after reduction were investigated by XRD and the morphology of the resulting CNTs was observed by TEM. The results showed that among the prepared series of La-Ni-O catalyst precursors, only those with catalytic activity were LaNiO 3 and La 2 NiO 4. However, the yield of CNTs prepared from LaNiO_3 is much higher than that of CNTs prepared from La_2NiO_4. According to the analysis, it is mainly related to the (111) crystal plane content of the nano-sized metal Ni in the product after being reduced. The (111) crystal plane content and the grain size of the nano- The greater the yield and the inner diameter.