PtSn/Al2O3/MCM-41催化剂的丙烷脱氢催化性能  

Catalytic Properties of PtSn/Al_2O_3/MCM-41 Catalysts for Propane Dehydrogenation

作　　者：黄丽华[1] 杨利利[1] 许波连[1] 范以宁[1] 

机构地区：[1]南京大学化学化工学院,介观化学教育部重点实验室,江苏省纳米技术重点实验室,南京210093

出　　处：《物理化学学报》2008年第7期1297-1301,共5页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展规划项目(2005CB221408)资助

摘　　要：用微型催化反应装置评价,并结合X-射线粉末衍射(XRD)、表面积和孔结构测试、程序升温还原(TPR)、氢化学吸附和热重分析等方法研究了负载型PtSn/γ-Al2O3,PtSn/MCM-41和PtSn/Al2O3/MCM-41催化剂的丙烷脱氢反应催化性能.发现PtSn/Al2O3/MCM-41催化剂具有较PtSn/MCM-41催化剂高的丙烷脱氢反应活性和较PtSn/γ-Al2O3催化剂高的反应稳定性.实验结果表明,纯硅MCM-41载体表面的锡物种因与载体相互作用较弱故易被还原,导致铂金属分散度和催化剂的丙烷脱氢活性较低.用Al2O3修饰MCM-41可以增强Sn物种与Al2O3/MCM-41载体之间的相互作用,提高PtSn/Al2O3/MCM-41催化剂铂金属分散度和丙烷脱氢催化活性.并且,积炭后的PtSn/Al2O3/MCM-41催化剂具有较高的铂金属表面裸露度,故具有较高的丙烷脱氢反应稳定性.PtSn/Al2O3/MCM-41催化剂优良的丙烷脱氢催化性能可能不仅与Sn-载体Al2O3/MCM-41较强的相互作用有关,而且与Al2O3/MCM-41载体的介孔结构有关.The catalytic properties of PtSn/γ-Al2O3, PtSn/MCM-41 and PtSn/Al2O3/MCM-41 catalysts for propane dehydrogenation were studied using microreactor tests combined with X-ray diffraction （XRD）, BET surface area and pore structure measurements, temperature-programmed reduction （TPR）, H2-chemisorption and thermogravimetric （TG） analysis. It was shown that the PtSn catalysts supported on Al2O3-modified MCM-41 （Al2O3/MCM-41） exhibited higher activity than the PtSn/MCM-41 catalyst, and higher catalytic stability than the conventional PtSn/γ-Al2O3 catalyst for propane dehydrogenation. The characterization results of the catalysts revealed that on the surface of pure MCM-41, the dispersed Sn species were easier to be reduced to metallic state due to weak interaction of Sn with MCM-41 support, resulting in lower Pt dispersity and thus lower catalytic activity. In contrast, modifying the surface of MCM-41 by alumina could enhance the interaction between Sn and Al2O3/MICM-41 support, and increase Pt dispersity and catalytic activity for propane dehydrogenation. Moreover, the PtSn/Al2O3/MCM-41 catalysts had larger bare fraction of Pt surface after coke deposition, leading to their higher catalytic stability than the PtSn/γ-Al2O3 catalyst. It is suggested that the unique catalytic properties of PtSn/Al2O3/MCM-41 catalysts are correlated not only to the strong interaction of Sn with Al2O3/MCM-41 support but also to the mesoporous structure of the Al2O3/MCM-41 support.

关 键 词：PT SN MCM-41 AL2O3 丙烷脱氢 

分 类 号：O643.32[理学—物理化学]