Mo、W对Ni/γ-Al_2O_3催化剂烯烃加氢性能的影响

Effect of Mo and W addition on performance of Ni/γ-Al_2O_3 catalyst for olefins hydrogenation

采用浸渍法制备了一系列NiM/γ-Al2O3(M＝Mo、W)催化剂.通过馏分油(沸点70 ℃～350 ℃)烯烃的加氢饱和,考察了Mo、W对Ni基催化剂加氢性能的影响,并采用TPR、XRD、XPS对催化剂进行表征.TPR结果表明,添加助剂Mo(W)降低了低温还原峰温度,但还原度有所降低,而且NiMo催化剂还原度的降低幅度比NiW催化剂更大;XRD结果表明,Mo(W)的添加提高了活性组分Ni的分散度,并且Mo的助分散作用优于W;XPS结果表明,Mo(W)的引入提高了催化剂体系'表面NiAl2O4'的比例,Ni2p3/2谱峰的化学位移说明助剂的添加增强了Ni与载体γ-Al2O3之间的相互作用.

A series of alumina supported Ni,Mo-Ni and W-Ni catalysts were prepared by co-impregnation and the structure and nickel species were characterized by XRD,TPR and XPS.The effect of additive Mo(W) on catalyst activity for the hydrogenation of olefins in the fraction(boiling spread: 70 ℃～350 ℃) was studied.TPR characterization reveals the addition of additives shifts the high-temperature reduced peak to higher temperature but the low-temperature reduced peak to lower one.For the decrease of deoxidizing temperature,the effect of Mo is better than that of W.XRD measurements show that Mo and W increase the dispersion of NiO on the supports in the order of Mo>W.XPS analyse reveals the ratio of surface NiAl2O4 increases due to the presence of Mo and W.The shift of Ni2p3/2 peak indicates a stronger interaction between the NiO and γ-Al2O3 support.