锡组分状态对Pt/Al_2O_3丙烷脱氢性能的影响  

Effect of Sn Transformation on Catalytic Performance of Pt/Al_2O_3 Catalyst for Propane Dehydrogenation

作　　者：吴文海[1] 李应成[1] 吴省[1] 缪长喜[1] 贺鹤勇[2] 陈庆龄[1] 

机构地区：[1]中国石油化工股份有限公司上海石油化工研究院,上海201208 [2]复旦大学化学系,上海200433

出　　处：《化学反应工程与工艺》2009年第1期41-45,共5页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金(20736011)

摘　　要：采用浸渍法制备了不同Sn组分含量以及一定量的金属钠组分的Pt-Sn/Al_2O_3催化剂,并采用程序升温还原(TPR),光电子能谱(XPS)和程序升温氧化(TPO)等手段对催化剂进行了表征。研究表明,Sn组分状态与Sn组分以及Na组分的相对含量有关,在Sn与Pt物质的量之比小于5(Pt质量负载量0.4%)时,Sn组分在催化剂表面以氧化态的形式存在。此种催化剂用量为0.32 g时,在常压、550℃、丙烷质量空速3.4 h^(-1)的条件下,反应6.5 h丙烷转化率达43.1%,丙烯选择性达98.0%。若Sn含量更高,将导致Sn被还原析出,形成Sn与Pt合金。当Sn与Pt物质的量之比为1时,引入1.2%的NaCl不会影响Sn组分状态;当Sn与Pt物质的量之比为5,引入相同量的NaCl,导致催化剂表面的Sn组分容易被氢气还原。Pt-Sn-Na/Al2O3 catalysts with different Sn loading amount were prepared by impregnation method and characterized by temperature programmed reduction （TPR）, X-ray photoelectronic spectroscopy （XPS） and temperature programmed oxidation （TPO）. The results indicated that the state of Sn was related with the amount of Sn and Na. When the molar ratio of Sn to Pt was less than 5 （Pt mass fraction 0. 4%）, Sn existed in oxide state on catalyst surface. Highly propylene selectivity （98.0%） and propane conversion （43.1%） were obtained under the conditions of atmosphere, temperature 550℃, time 6.5 h, propane mass space velocity 3.4 h^-1 and the catalyst amount 0.32 g. Higher Sn loading led to Sn reduction and the formation of alloy, which caused the decrease of catalytic activity. When the molar ratio of Sn to Pt was 1, the tin state was no effected by the addition of NaCl mass fraction 1.2%, while the same amount of NaCl destabilizes tin oxide on catalyst surface when the molar ratio of Sn to Pt was 5.

关 键 词：锡 丙烷 脱氢 丙烯 铂 

分 类 号：O643.32[理学—物理化学]