【摘要】 采用直接合成和AlCl3接枝改性两种方法制备了Al MCM 41载体,用等体积浸渍法制备了MCM 41负载Pd Pt的双金属催化剂。所得催化剂通过XRD、N2吸附脱附和TPR测定,以萘加氢为模型反应,考察了该催化剂的萘加氢活性和耐硫性能。结果表明,直接合成和接枝改性均可获得结构比较均一的载体。在相同的nSi/nAl下,接枝法可以保持更高的结晶有序程度和比表面积。焙烧后的催化剂有几种可还原物种。以接枝法制备的Al MCM 41载体的nSi/nAl=5时,催化剂的萘加氢活性最大(准一级速率常数为1.743);以直接法合成的Al MCM 41载体的nSi/nAl=10时,催化剂具有最高的萘加氢活性(准一级速率常数为1.782)和最优的耐硫性能(准一级速率常数为1.213)。更多还原

【Abstract】 Al-MCM-41 supports were prepared by two methods, direct synthesis and method of grafting with AlCl₃. Pd-Pt bimetallic catalysts were prepared by incipient wetness method. Hydrogenation of naphthalene was chosen to evaluate the hydrogenation activity and sulfur tolerance. The results of XRD and N₂ adsorption measurements indicated that all the Al-MCM-41 supports possessed uniform structure.The supports prepared by grafting method had higher orderness of crystallinity and higher specific area as compared with the Al-MCM-41 supports prepared by direct synthesis of the same silica to alumina ratio. The TPR analysis indicated that several metal species existed in the calcined catalysts. The results of naphthalene hydrogenation revealed that the maximum activity（k₁=1.743） of the catalyst supported on Al-MCM-41 prepared by grafting method was obtained when its silica to alumina mol ratio was 5, while the maximum activity（k₁=1.782） and sulfur tolerance（k₁s=1.213） of the catalyst supported on Al-MCM-41 directly synthesized occurred at its silica to alumina mol ratio of 10.更多还原