高质量单壁纳米碳管的CVD法合成及催化剂酸碱性对碳管生长的影响

Synthesis of High Quality Single-Walled Carbon Nanotubes by CVD and Effect of Catalyst’s Acidity-Basicity on Nanotubes Growth

采用燃烧法制备了Fe/Mo/MgO催化剂,用化学气相沉积法在1000℃下催化裂解甲烷制得了单壁纳米碳管.实验结果表明,550℃下焙烧的催化剂效果最好,适宜的酸碱性应该是催化剂具有较高活性的原因.用扫描电镜、透射电镜、高分辨透射电镜、热重分析和拉曼光谱等方法对制备的纳米碳管粗产品进行了表征.结果表明,该产物确为高质量单壁纳米碳管,其形态基本都以束状存在,且单壁纳米碳管直径分布较窄(0.85～1.22nm);对反应气氛的考察表明,CH4/N2=50/300为最佳,该气氛下所制得粗产物中单壁碳管的含量接近40%,经稀盐酸室温处理后,碳管含量可达到75%以上.

High quality SWNTs are synthesized by catalytic decomposition of CH4/N-2 at 1000 degrees C on the Fe-Mo/ MgO catalyst prepared by a combustion method. The best combustion temperature is 550 degrees C for the catalyst. The fitting acidity-basicity can explain the high catalytic performance. The as-prepared SWNTs have been characterized by SEM, TEM, HRTEM, TGA and Raman spectroscopy. The results show that the synthesized SWNTs are usually bundles and they have a narrow diameter distribution with 0.85 similar to 1.22 nm. The best reaction atmosphere is 50/300 for the catalyst. Under this ratio of CH4/N-2, the content of the prepared raw SWNTs is close to 40% weighting over the catalyst. After the raw SWNTs are treated by diluted HCl at room temperature, the sample can contain yield of SWNTs to over 75%.