Pd/ZrO_2-Al_2O_3催化剂加氢脱硫性能的研究

Studies of Hydrodesulfurization Properties over Pd/ZrO_2-Al_2O_3 Catalysts

采用等体积浸渍法制备了一系列不同Zr含量的ZrO2-Al2O3复合载体和Pd/ZrO2-Al2O3催化剂,利用连续流动微反装置考察了Pd/ZrO2-Al2O3催化剂的噻吩加氢脱硫(HDS)性能,并运用程序升温还原(TPR),程序升温脱附(H2-TPD,NH3-TPD)和N2物理吸附等技术对载体及催化剂进行了表征.结果表明:ZrO2-Al2O3复合载体中Zr含量对Pd基催化剂的HDS性能有较大影响,加入适量Zr可增大Pd/Al2O3催化剂的分散度及H2吸附量和酸量,减弱活性组分与载体的相互作用,使活性中心和噻吩吸附位增多以及活化能降低,从而有利于Pd基催化剂HDS反应活性的提高,w(Zr)为9%时Pd/ZrO2-Al2O3催化剂的活性最好.

A series of ZrO2-Al2O3 mixed oxides and Pd/ZrO2-Al2O3 catalysts with various zirconium contents were prepared by the impregnation method. HydrodesuIfurization （HDS） reaction of thiophene over Pd/ZrO2-Al2O3 catalysis was carried out in a flow reactor. XRD, TPR, H2-TPD, NH3-TPD and nitrogen adsorption techniques were used to characterize the samples. The result showed that the effect of zirconium content on HDS properties was observed over Pd/ZrO2-A1203 catalysts. Introducing suitable zirconium into Pd/Al2O3resulted in relatively higher dispersed-metal, more acid amount, more H2 adsorbed amount and weaker metal-support interaction, and also leaded to the increase of the adsorption sites of thiophene and active centres, the decrease of the apparent activation energy, all of above mentioned factors were favorable for the HDS of thiophene. The maximum HDS activity was observed for Pd/ZrO2-Al2O3 catalysts with zirconium content of 9% .