Y沸石载体酸量对贵金属催化剂加氢活性和抗硫性能的影响  

Effect of Surface Acid Amount of Y Zeolite on Activity and Sulfur Tolerance of Supported Pd-Pt Catalysts

作　　者：刘会茹[1] 李建荣[1] 赵地顺[2] 李永丹[1] 

机构地区：[1]天津大学化工学院催化科学与工程系天津市应用催化科学与工程重点实验室,天津300072 [2]河北科技大学化工与制药工程学院,河北石家庄050018

出　　处：《催化学报》2007年第3期274-280,共7页

基　　金：国家自然科学基金(20425619).

摘　　要：采用水蒸气脱铝获得表面酸量不同的USY载体,并用离子交换法制备了金属(Pd+Pt)含量为1.15%的双金属催化剂.用NH3的程序升温脱附、X射线衍射、N2吸附-脱附和X射线光电子能谱等方法表征了载体和催化剂.以四氢萘加氢为探针反应,4,6-二甲基二苯并噻吩为硫源,在固定床反应器中考察了催化剂的活性和耐硫性.结果表明硫含量为200μg/g时,载体酸量为626和203μmol/g的两个催化剂的耐硫性最好,而载体酸量更低和更高的催化剂的耐硫性较差,表明载体的酸量太大或太小都不利于催化剂的抗硫性.X射线能量散射分析表明,酸量大时S在酸性位吸附很多,这可能导致催化剂中毒.酸量过小的催化剂抗硫性差则与金属中心缺电子效应较小有关.USY zeolite supports with different acid amounts were obtained by steam dealumination. Dual metal catalysts with a total loading of Pd and Pt of 1.15 % were prepared by the ion-exchange method. The supports and catalysts were characterized by temperature-programmed desorption of ammonia, X-ray diffraction, nitrogen adsorption, and X-ray photoelectron spectroscopy. The catalytic activity for the hydrogenation of tetralin was examined with a fixed-bed continuous-flow reactor operating at 4.0 MPa. The sulfur tolerance was tested with a feed of 200μg/g sulfur in the form of 4,6-dimethyldibenzothiophene. The two catalysts supported on USY zeolites with surface acid amounts of 626 and 203 /μmol/g, respectively, showed excellent sulfur tolerance, while the catalysts of higher and lower acid amount showed decreased sulfur tolerance. Energy dispersive spectroscopic analysis proved that the support with a large acid amount adsorbed more sulfur, which might lead to the lower sulfur tolerance of the catalyst. The low sulfur tolerance of the catalyst with a low acid amount was attributed to the insignificance of the electron deficiency of the metal particles.

关 键 词：Y沸石 水蒸气 脱铝 钯 铂 四氢萘 加氢 耐硫性 溢流氢 

分 类 号：O643.36[理学—物理化学]