论文部分内容阅读
采用多步法依次将制备的Fe3O4纳米颗粒和Pt纳米颗粒负载到多壁碳纳米管(MCNT)上得到Pt/Fe3O4-MCNT磁性催化剂,以X射线衍射(XRD)、透射电镜(TEM)、超导量子干涉磁强计(SQUID)和热重-差热分析(TG-DTA)对Pt/Fe3O4-MCNT磁性催化剂的结构和磁性质进行了表征。研究发现预制备的Fe3O4纳米颗粒与Pt纳米颗粒均匀地分散于MCNT上,新制备以及多次使用后的Pt/Fe3O4-MCNT室温下都具有良好的超顺磁性。研究了Pt/Fe3O4-MCNT磁性催化剂上的肉桂醛选择性加氢反应,结果显示催化剂具有良好的C=O加氢活性,肉桂醛转化率在50%左右时,肉桂醇选择性可达96%以上。尺寸均一的Pt粒子均匀的分散在催化剂上可能是催化剂具有良好的C=O加氢选择性的重要原因。在外加磁场作用下催化剂可以高效地从液相反应体系中分离,经多次循环使用后仍具有良好的催化性能。
The prepared Fe3O4 nanoparticles and Pt nanoparticles were loaded onto multi-walled carbon nanotubes (MCNTs) by a multi-step method to obtain Pt / Fe3O4-MCNT magnetic catalysts. The XRD, TEM, The structure and magnetic properties of Pt / Fe3O4-MCNT magnetic catalysts were characterized by SQUID and TG-DTA. The results showed that the prepared Fe3O4 nanoparticles and Pt nanoparticles were uniformly dispersed on MCNTs. The new preparation and the repeated use of Pt / Fe3O4-MCNT showed good superparamagnetism at room temperature. The selective hydrogenation of cinnamaldehyde on the Pt / Fe3O4-MCNT magnetic catalyst was studied. The results showed that the catalyst had good hydrogenation activity of C = O. When the cinnamaldehyde conversion was about 50%, the cinnamyl alcohol selectivity was up to 96% the above. The homogeneous dispersion of Pt particles on the catalyst may be an important reason for the good selectivity of the catalyst for C = O hydrogenation. Under the action of applied magnetic field, the catalyst can be efficiently separated from the liquid reaction system and still has good catalytic performance after being recycled for many times.