OMS-2/Al2O3/堇青石整体式催化剂的制备及其催化性能研究

以Al₂O₃/堇青石蜂窝陶瓷为载体,氧化锰八面体分子筛(OMS-2)为活性组分,采用涂覆法制备了系列整体式催化剂。考察了黏合剂种类和活性组分涂覆次数对二甲醚(DME)催化燃烧性能的影响,并对催化剂进行XRD、BET、SEM、H₂-TPR、O₂-TPD等表征。结果表明,以甲氧基聚乙二醇为黏合剂经一次涂覆制备的整体式催化剂的性能最佳,活性组分OMS-2以相互交织的簇体均匀分布在载体上,并与Al₂O₃之间存在较强的相互作用。涂层的添加有效增加了催化剂的比表面积,提高了催化剂的性能,最佳催化活性t₉₀为257 ℃。

Preparation and catalytic performance of OMS-2/Al2O3/cordierite monolithic catalyst

Monolithic catalysts for catalytic combustion of dimethyl ether (DME) were prepared by a dip-coating method using Al₂O₃/cordierite as support and manganese oxide octahedral molecular sieve (OMS-2) as active component. The effect of different types of organic polymer binder and the coating times of active component on the performance of DME combustion were investigated. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), hydrogen temperature-programmed reduction (H₂-TPR) and oxygen temperature-programmed desorption (O₂-TPD) techniques. The results showed that the best catalyst was the one using methoxy polyethylene glycol (MPEG) as the coating binder by one-time coating. The active component OMS-2 was in a cluster form and homogeneously dispersed on the surface of the support because of the strong interaction between OMS-2 and Al₂O₃ coating. The Al₂O₃ coating could significantly improve the surface area of catalysts, and thus enhance the activity performance. The highest catalytic activity for DME combustion with a complete combustion temperature (t₉₀) of 257 ℃ was obtained.