纳米洋葱碳的制备及其纯化研究

Fabrication and purification of carbon nano onions

摘要: 以甲烷为碳源, 316 号不锈钢网为催化剂,800℃下催化裂解甲烷,采用化学气相沉积法制备平均粒径为70 ~ 100 nm 纳米洋葱碳,通过酸洗-低温煅烧-磁选方法对洋葱碳进行纯化处理。X 射线衍射、扫描电子显微镜、透射电子显微镜、红外吸收光谱、拉曼光谱和振动样品磁强计对样品的形貌结构、物相组成及磁性能进行表征分析。结果表明,酸洗-低温煅烧能有效去除初产物中裸露的催化剂颗粒及无定型碳,磁选则实现将内包有Fe-Ni磁性催化剂的洋葱碳与空心的洋葱碳分离,最终获得纯净的空心纳米洋葱碳。

Abstract: Carbon nano onions (CNOs) with diameters of 70-100 nm were fabricated by chemical vapor deposition at 800
℃, using methane as carbon source and high-temperature steam treated 316 stainless steel mesh as catalyst. The CNOs were isolated from the substrate by HNO3 refluxing, calcination in air at 500℃ and magnetic separation. The morphology, microstructures and magnetic properties of the CNOs were characterized by SEM, TEM, XRD, Raman spectroscopy, FTIR spectroscopy and vibration sample magnetometer tests. Results showed that the surface attached catalyst particles and amorphous carbon can be effectively removed from raw CNOs through HNO₃ refluxing and calcination. Magnetic separation can selectively remove the CNOs encapsulating a Ni,Fe magnetic catalyst from the CNOs that are hollow.