基于微反应器制备催化剂的老化研究

Aging study of catalyst preparation based on microreactor

传统间歇反应混合效率低,制备的催化剂颗粒均匀性较差。基于微反应器制备了Fe-Mo/Al_(2)O_(3)催化剂,提高了共沉淀过程混合的均匀性,考察了老化温度及老化时间对催化剂微结构及碳纳米管形貌的影响。并借助于BET、SEM、Raman等检测方法对催化剂及碳纳米管进行表征。研究表明:在催化剂制备过程中老化时间、老化温度均会影响催化剂的微观结构(比表面积、孔径、孔容)。对碳纳米管的检测发现,老化时间对碳纳米管的灰分、石墨化程度影响较大,而老化温度对碳纳米管的导电性影响较大。老化时间为4 h时,碳纳米管的灰分质量分数最小,为2.39%,碳纳米管石墨化程度最高,其I_(D)/I_(G)值为0.84。老化温度为40℃时,碳纳米管的导电性最好,其四探针电阻率为95.3 mΩ·cm。

The traditional batch reaction has low mixing efficiency and poor uniformity of the prepared catalyst particles.Fe-Mo/Al_(2)O_(3)catalyst was prepared based on a micro-reactor to improve the mixing uniformity of the coprecipitation process.The effects of aging temperature and aging time on the microstructure of the catalyst and the morphology of carbon nanotubes were investigated.BET,SEM,Raman and other detection methods were used to characterize the catalyst and carbon nanotubes.The results show that aging time and aging temperature during the catalyst preparation process affect the microstructure of the catalyst,such as specific surface area,pore size,and pore volume.By inspecting carbon nanotubes,the aging time has a greater impact on the ash content and graphitization degree of the carbon nanotubes,while the aging temperature has a greater impact on the conductivity of the carbon nanotubes.When the aging time is 4 h,the ash mass fraction of carbon nanotubes is the smallest(2.39%),and the graphitization degree of carbon nanotubes is the highest,with I_(D)/I_(G)value of 0.84.When the aging temperature is 40℃,the conductivity of carbon nanotubes is the best,and its four-probe resistivity is 95.3 mΩ·cm.