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采用微乳法室温下合成了γ-Al2O3/SiO2/Fe3O4磁性复合颗粒为载体负载的纳米钯催化剂。利用透射电镜、x射线光电子能谱和振动样品磁强计等手段对催化剂进行表征,评价了催化剂对硝基苯加氢制苯胺反应的催化活性。结果表明,通过调控反应条件,可在平均粒径为200nm左右的磁性载体上负载10nm左右均匀分散的Pd纳米颗粒,整个催化剂呈现超顺磁性;在催化剂磁含量为8%、Pd负载量1%、反应时间40min、反应温度50℃,反应压力0.5MPa条件下,硝基苯的转化率可以达到100%,催化剂重复使用10次时仍可保持很高的催化活性,并可在外磁场作用下快速分离与回收。
The nano-palladium catalyst supported on γ-Al2O3 / SiO2 / Fe3O4 magnetic composite particles was synthesized by microemulsion method at room temperature. The catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometer. The catalytic activity of the catalyst for the aniline reaction of hydrogenation of nitrobenzene was evaluated. The results showed that Pd nanoparticles with a mean diameter of about 200 nm could be uniformly dispersed on the magnetic carrier with an average diameter of about 200 nm by adjusting the reaction conditions, and the whole catalyst showed superparamagnetism. When the catalyst magnetic content was 8% and the Pd loading was 1% , The reaction time is 40min, the reaction temperature is 50 ℃ and the reaction pressure is 0.5MPa, the conversion of nitrobenzene can reach 100%. When the catalyst is reused for 10 times, the catalytic activity can be kept very high, and under the action of external magnetic field, Separation and recovery.