OMS-2/堇青石整体式催化剂的制备及其对二甲醚燃烧的催化性能

Preparation of OMS-2/Cordierite Monolithic Catalysts and Their Catalytic Performance for Dimethyl Ether Combustion

以有机物为粘合剂,采用涂覆法制备了氧化锰八面体分子筛(OMS-2)/堇青石整体式催化剂,采用热重-差热分析、扫描电镜、X射线衍射、H2程序升温还原和O2程序升温脱附等技术对催化剂进行了表征,考察了有机粘合剂种类及其用量对二甲醚(DME)催化燃烧性能的影响.结果表明,在有机粘合剂聚乙烯醇1799(其质量含量为3%)的作用下,OMS-2以相互交织的簇体均匀分布于堇青石表面,且粘附力较强,制备的整体式催化剂在DME催化燃烧中表现出最优的催化性能,起燃温度T10=169oC,完全转化温度T90=243oC;催化剂使用后再经高温焙烧其活性仍能保持稳定,表现出较高的重复使用性.

Manganese oxide octahedral molecular sieve （OMS-2）/cordierite monolithic catalysts were prepared by a coating method using poly（vinyl alcohol） （PVA） or poly（ethylene glycol） （PEG） as the binders.The catalysts were characterized by thermogravimetry-differential thermal analysis,scanning electron microscopy,X-ray diffraction,H2 temperature-programmed reduction （H2-TPR）,and O2 temperature-programmed desorption （O2-TPD）.The catalytic activity of the catalysts in dimethyl ether （DME） combustion was evaluated.OMS-2 could be loaded on the cordierite with good adhesion stability by the coating method.OMS-2 was in a cluster form and was homogeneously dispersed on the surface of the support.The O2-TPD and H2-TPR results showed that the monolithic catalysts were rich in facile lattice oxygen and can activate oxygen and be easily reduced by H2,which led to excellent performance in the DME catalytic combustion.The catalyst with 3% PVA-1799 showed the highest catalytic activity for DME combustion with a light-off temperature （T10） of 169 oC and a complete combustion temperature （T90） of 243 oC.The T90 was raised to 302 oC over the used catalyst after being recalcined at 550 oC for 5 h,but the catalytic activity remained stable after nearly 100 h on stream with recycling 9 times.This indicated that the catalyst was recyclable.