Al_(2)O_(3)载体改性对乙炔加氢催化剂的影响

Effect of Al_(2)O_(3) support modification on acetylene hydrogenation catalyst

对1100℃高温焙烧的Al_(2)O_(3)载体进行不同温度水热处理后,采用等体积浸渍法负载Pd,Ag组分制备了一系列PdAg/Al_(2)O_(3)催化剂,并研究了PdAg/Al_(2)O_(3)催化剂对乙炔选择加氢性能的影响。利用XRD,N_(2)吸附-脱附,NH_(3)-TPD,XPS,HRTEM等方法对催化剂进行表征。表征结果显示,水热处理后载体的比表面积、孔体积、孔径等均发生变化;随着水热处理温度的提高,载体表面酸量增加,催化活性有了大幅提升。实验结果表明,Al_(2)O_(3)载体在160℃水热处理后,制备的催化剂性能最优;在一定反应条件下,乙炔转化率可达98.88%,乙烯选择性为90.23%,丙炔与丙二烯的混合物转化率为54.83%。

The effect of PdAg/Al_(2)O_(3)catalyst on the selective hydrogenation of acetylene after hydrothermal treatment of supported Al_(2)O_(3)was studied.A series of PdAg/Al_(2)O_(3)catalysts were prepared by impregnating and supporting Pd,Ag components with equal volume after calcining Al_(2)O_(3)at 1100℃with different hydrothermal temperatures.The analysis was carried out by means of XRD,N_(2) adsorption-desorption,NH_(3)-TPD,XPS and HRTEM.The results showed that the specific surface area,pore volume,and pore diameter of the hydrothermally treated support had changed compared with the unhydrothermally treated support.With the increase of the hydrothermal treatment temperature,the amount of acid on the surface of the support increased,and the catalytic activity was greatly improved.After the Al_(2)O_(3)support was hydrothermally treated at 160℃,the prepared catalyst had the best performance.Under certain reaction conditions,the conversion of acetylene reached 98.88%,the selectivity of ethylene was 90.23%,and the conversion of mixture of propyne and propadiene was 54.83%.