论文部分内容阅读
通过浸渍及水热处理获得MgO负载的Fe基催化剂,并将其用于化学气相沉积过程裂解甲烷获得碳纳米管.结果表明,单/双/多壁碳纳米管可选择性地生长在Fe负载量不同的Fe/MgO催化剂上.当Fe负载量仅为0.5%时,铁原子在载体表面烧结为0.8～1.2nm的铁颗粒,碳在这种小颗粒上以表面扩散为主,导致单壁碳纳米管形成,并且单壁碳纳米管的选择性高达90%.当Fe负载量提高到3%时,铁原子聚集成约2.0nm的颗粒,在化学气相沉积中生长碳纳米管时,碳在Fe催化剂颗粒中的体相扩散的贡献增大,在表相扩散和体相扩散的共同作用下,双壁碳纳米管的选择性显著增高.当进一步增加Fe负载量时,铁原子烧结形成1～8nm的颗粒,经过化学气相沉积,在催化剂上生长了单、双、多壁碳纳米管.随着Fe在MgO载体上负载量的增加,管径、管壁数以及半导体管的含量都增加.本研究提供了一种适合大批量选择性生长单/双/多壁碳纳米管的方法.
The MgO-supported Fe-based catalyst was obtained by impregnation and hydrothermal treatment and used for chemical vapor deposition to crack the methane to obtain carbon nanotubes.The results show that the single / double / multi-walled carbon nanotubes can be selectively grown at Fe loading On Fe / MgO catalysts, when the Fe loading is only 0.5%, the iron atoms are sintered on the surface of the carrier to 0.8 ~ 1.2nm iron particles. Carbon is mainly surface diffusion on these small particles, Nanotubes were formed, and the selectivity of single-walled carbon nanotubes was as high as 90% .When the Fe loading was increased to 3%, iron atoms were aggregated into particles of about 2.0 nm, carbon nanotubes were grown in chemical vapor deposition The contribution of bulk phase diffusion in the Fe catalyst particles increases, and the selectivity of the double-walled carbon nanotubes increases significantly with the combination of surface phase diffusion and bulk diffusion. When the Fe loading is further increased, the iron atom sintering forms 1 ~ 8nm, single-walled, double-walled and multi-walled carbon nanotubes were grown on the catalyst by chemical vapor deposition.With the increase of the loading of Fe on the MgO carrier, the diameter of the tube, the number of the tube wall and the content of the semiconductor tube increased This study provides a suitable for large quantities of selective students Double Single / Multi-Method / walled carbon nanotubes.