Ni负载量对负载型Ni/SiO2催化剂结构及性能的影响

采用等体积浸渍法制备了Ni/SiO2催化剂,研究了镍负载量对二硝基甲苯(DNT)加氢制备甲苯二胺(TDA)的催化性能的影响,并通过XRD,BET,H2-TPR,H2-TPD方法对催化剂微观结构进行了表征。结果表明,Ni/SiO2催化剂在二硝基甲苯加氢合成甲苯二胺的反应中表现出良好的活性和选择性。当Ni负载量(即Ni与SiO2的质量比m(Ni):m(SiO2))≤28%时,随着镍负载量的增加,Ni活性中心数逐渐增大,催化剂的活性逐渐升高;而当Ni负载量>28%时,Ni活性组分在载体表面发生团聚,Ni活性中心数减少,催化剂的活性和选择性下降。当镍的负载量为28%时,DNT转化率达到了93.68%,TDA选择性为97.73%。

The Effect of Ni Loading on the Microstructure and the Catalytic Performance of Ni/SiO2

A series of Ni/SiO2 catalysts were prepared by impregnation method,and the effect of Ni loading on the catalytic performance for dinitrotoluene hydrogenation was studied.XRD,BET,H2-TPR and H2-TPD were used to examine the microstructure of Ni/SiO2.The results show that Ni/SiO2 catalysts exhibited high activity and selectivity in hydrogenation of dinitrotoluene to diaminotoluene.When the Ni loading was smaller or equal to 28%,the amount of Ni activity center and the performance of Ni/SiO2 were enhanced with the increase of Ni loading.When the Ni loading was above 28%,the Ni aggregated on the surface of SiO2,which led to the decrease of the amount of Ni activity center and the performance of the catalyst.When Ni loading was 28%,the conversion of the DNT and the selectivity of TDA reached 93.68 % and 97.73 %,respectively.