预还原催化剂LaNiO3,La4Ni3O10,La3Ni2O7和La2NiO4催化分解CH4制碳纳米管的研究

A Study on Production of Carbon Nanotubes by Decomposition of CH4 over the Pre- reduced Catalysts LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4

通过预还原的LaNiO3,La4Ni3O10,LaNi2O7和La2 NiO4催化分解CH4可以制备大量高度石墨化的碳纳米管.还原前后的催化剂的结构和组分通过X射线衍射(XBD)测定.所制得的碳纳米管由扫描电镜(TEM)、X射线光电子能谱(XPS)表征.碳纳米管在空气中的热氧化性由热重实验(TG)测定.实验结果表明不同催化剂前驱中的La/Ni比会影响碳纳米管的管径分布和石墨化程度.La/Ni比越小,碳纳米管的管径越大,石墨化程度越高.

Carbon nanotubes of narrow size distribution can be mass produced in the catalytic decomposition of CH4 over pre - reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4. The structure and component of the fresh and reduced LaNiO3, La4Ni3O10, La3Ni2O7 and La2NiO4 were determined by X - ray diffraction (XRD). The carbon nanotubes obtained were characterized by means of transmission electron microscopy (TEM), X - ray photoelectron spectroscopy (XPS). Thermal oxidation of carbon nanotubes in air was performed by thermogravimetric experiment (TG). The results reveal that a lower La/Ni ratio of the catalysts would lead to a wider diameter distribution and a higher degree of graphitic nature.