【摘要】 实验发现乙炔在氢气与氮气气氛中催化裂解产物完全不同,反应温度973K,氮气气氛下,乙炔在LaFeO3纳米催化剂上裂解为碳纳米管,平均管径为30nm;在氢气气氛中乙炔主要在热电偶上裂解为碳纤维,直径平均为600nm左右。实验在没有催化剂存在时,对乙炔直接热裂解进行了研究.结果表明在没有氢气条件下,乙炔很少积碳;随氢气量的增加乙炔在热电偶上的积碳量逐渐增加,沉积的碳均成纤维状结构,平均直径随氢气量的增加逐渐增大。在1073K氢气气氛下,乙炔裂解产物中发现了大量螺旋状结构的碳纤维,其直径为80～200nm,长度一般在几μm～十几μm。更多还原

【Abstract】 The effects of reaction atmosphere (hydrogen or nitrogen) on catalytic decomposition of C2H2 were investigated. The results showed that the carbon nanotubes (CNTs) were obtained using LaFeO3 catalyst in the nitrogen atmosphere at 973 K; and they were multiwalled nanotubes of good quality with average diameter of 30 nm. While the carbon fibers (CF) with average diameter 600 nm were obtained in the hydrogen atmosphere at the same conditions. The direct thermal decomposition of C2H2 was investigated without any catalyst. The results showed that there was little deposited carbon on the thermalcoupling without hydrogen, the deposited carbon on the thermalcoupling increased with the flow of hydrogen. The morphological structures of the deposited carbon have been examined by SEM and TEM. The results indicated that the deposited carbon had a fibershape structure; and the average diameter of carbon fibers increased with the flow of hydrogen. The carbon fibers of helix structures were formed under the hydrogen atmosphere at 1073 K. This new structure likes twisting uniformly carbon fiber into a carbon nanorope with diameter of 80～200 nm and length ranging from 1 to 15μm.更多还原