La~2NiO~4催化制备纳米碳管

制备了四方结构复合氧化物La~2NiO~4，并以其为催化剂前体，甲烷和一氧化碳为碳，合成出大量高纯度的纳米碳管。XRD结果表明La~2NiO~4经还原后，在La~2O~3的隔离作用下Ni晶粒实现纳米级均匀分散。利用TEM，HRTEM，SEM，XRD，Raman等手段对所制备的纳米碳管进行了观察和表征。所制备的纳米碳管管径均匀、石墨化程度较高，该法制备纳米碳管工艺简单、产量较高，产品易于纯化。

Carbon nanotubes growth catalyzed by La~2NiO~4

Ni - based A2 BO4 - type mixed oxide, La2NiO4 , was prepared by means of a citric acid complexing method. X - ray diffraction pattern identified it as a single phase with a tetragonal K2 NiF4 structure in which Ni2 and La3 ions were evenly distributed. It also indicated the nickel existed mainly as Ni0 after reducing. Rare earth oxides, La2O3, could prevent transition metal from agglomerating and promote dispersion of nano -scale Ni0 particles, which was very advantageous for carbon nanotube growth. A large amount of carbon nanotubes from catalytic decomposition of CH4 and disproportionation of CO were obtained using La2 NiO4 oxides as catalyst precursor. The morphology of the carbon nanotubes was examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). High resolution transmission electron microscopy image and Raman spectrum of carbon nanotubes showed they were multi - walled nanotubes with a higher degree of graphitization.