水热法合成Ni(OH)_2/SiO_2催化剂制备碳纳米管:镍含量对碳纳米管管径和产率的影响

CVD Growth of Carbon Nanotube with Ni(OH)_2/SiO_2 Catalyst Synthesized by Hydrothermal Mthod:Influence of the Ni Content on the Diameter and Yield of Carbon Nanotube

以硝酸镍和正硅酸乙酯为主要原料,采用前驱物水热法制得不同镍含量的纳米Ni(OH)2/SiO2复合粉体,用复合粉体做催化剂催化裂解C2H2制得多壁碳纳米管粗产物.研究表明:在复合粉体Ni(OH)2/SiO2催化剂中,硅镍比在一定范围内(1:2～1:14),随着镍含量增加,粒径增大,结晶程度提高,催化剂活性先提高后下降,制得的碳纳米管纯度及产量先增后降,碳管的管径分布范围先窄后宽.催化剂硅镍比为1:12时,制得的碳纳米管纯度高,管径细而均匀(10～18nm),且粗产物数量较多(1g催化剂合成3.3g碳纳米管粗产物).

Ni(OH)_2/SiO_2 compound nano-particles were synthesized by hydrothermal method using the nitric acid and TEOS(tetraethyl orthosilicate) with different Ni content as the precursor materials .They were deoxidized by H_2 ,then catalyzed and cracked C_2H_2 to synthesize carbon nanotube original products.The results show that the diameters of Ni(OH)_2/SiO_2 compound nano-particles become larger,the proportion of the crystallization also rises with TEOS: nitric acid from 1:2 to 1:14,and the activity of the catalysts firstly increases,and then fall.And thus the purity and yield of the carbon nanotubes also firstly increase and fall later. First the ranges of the tube diameter of the carbon nanotubes were narrow,and then wider. When the TEOS: nitric acid of the catalyst was 1∶12, the purest MWCNTs with smaller(10-18nm) and more symmetrical diameter can be got.And the yield of the original product is high,that is,a (3.3g) carbon nanotubes original product is made from 1g catalyst.