Fe催化剂还原对CO歧化制备纳米碳纤维过程影响  

Synthesis of carbon nanofibers by CO disproportionation: Influence of iron catalyst reduction

作　　者：卢文新[1] 隋志军[1] 周静红[1] 李平[1] 陈德[2] 周兴贵[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237 [2]挪威科技大学化学工程系

出　　处：《中国科技论文在线》2011年第9期638-643,共6页

基　　金：教育部创新团队发展计划资助项目(IRT0721);国家自然科学基金重点项目(20736011);高等学校学科创新引智计划资助项目(B08021);科技部国际科技合作项目(2007DFC61690)

摘　　要：考察了Fe催化剂上CO歧化制备纳米碳纤维（CNFs）过程中催化剂的还原温度和还原时间对CNFs的生长速率、产率和形貌的影响。Fe3O4在500-600℃条件下还原处理,之后将其用于合成CNFs的催化剂。对还原处理后的催化剂进行XRD、TEM和SEM分析,结果表明随着还原时间和温度的增加,催化剂的相态不同,粒径也从20-30 nm增加到500-2 000 nm。催化剂的相态和粒径对CNFs的生长速率、产率和形貌结构有显著影响。还原处理后催化剂初始粒径较大时,催化剂在生长过程中发生多次分裂过程,生成的CNFs直径不均匀;催化剂初始粒径较小时,催化剂上大量积碳而快速失活。催化剂中同时存在Fe3O4和Fe时,制备的CNFs弯曲和团聚较为严重。600℃还原20 min的催化剂上可获得产率较高、躯干较直且直径较为均匀的CNFs。This study focuses on the effects of reduction temperature and time on the growth rate,yields and morphology of the CNFs synthesized by CO disproportionation on Fe catalyst.Fe3O4 catalysts were used to synthesize（CNFs） after reduced by H2 at 500-600 ℃.XRD,TEM and SEM characterization results of the reduced catalysts indicated that catalysts composition varied and the catalyst particle size increased from 20-30 nm to 500-2 000 nm as the reduction temperature and time increased.Catalyst phase and particle size have great impact on the growth rate,yields and morphology of the as-synthesized CNFs.The fragmentation of the large catalyst particles occurs during the synthesis process and leads to a broad distribution of diameters of the synthesized CNFs Amorphous carbon was easily deposited on very small Fe particles,which results in the fast deactivation of the catalyst.Seriously curving and aggregated CNFs were formed on the catalyst particle coexisting of Fe3O4 and Fe.Over the catalyst reduced at 600 ℃ and for 20 min,straight and uniform CNFs were synthesized with a high yield.

关 键 词：催化反应工程 催化剂 还原 纳米碳纤维 CO 歧化反应 

分 类 号：TQ342.742[化学工程—化纤工业]