催化裂解法制备大孔径碳纳米管

Catalytic Growth of Carbon Nanotubes with Large Inner Diameters

Ni-Cu-Al催化剂中加入少量碳酸钠,催化裂解甲烷制备了大孔径碳纳米管,碳纳米管的产量为2.4g/g.cat。用这种方法制备的碳纳米管的内径约为20 nm^60 nm,外径约为40 nm^80nm。用扫描电镜(TEM)和X射线衍射(XRD)研究了碳纳米管的形貌和微结构。分析结果表明:用这种方法制备的碳纳米管不仅内径较大而且石墨化程度较高。碳酸钠的加入引起了甲烷转化率和碳产率的轻微下降。实验结果表明:碳酸钠是一种温和的毒物,它能影响Ni-Cu-Al催化剂的催化活性,导致大孔径碳纳米管的生成。文中还讨论了大孔径碳纳米管的生长机理。

Carbon nanotubes（2.4g/g, cat） with large inner diameters are synthesized through pyrolysis of methane on a Ni - Cu - Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of carbon nanotubes prepared by this method is about 20 nm - 60 nm, while their outer diameter is about 40 nm - 80 nm. Transmission electron microscopy（TEM） and X - ray diffraction （XRD） are employed to investigate the morphology and microstructures of carbon nanotubes. The analyses show that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about slight decreases in the methane conversions and the yield of carbon. Our experiments results show sodium carbonate is a mildly toxic material that influences the catalytic activity of the Ni - Cu - Al catalyst and results in the formation of the carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.