铜基小孔分子筛柴油车尾气脱硝催化材料研究进展

 柴油车尾气排放是大气污染物氮氧化物(NO_x)的主要来源之一。氨选择性催化还原技术(NH₃-SCR)具有高效率、低成本等特征,已成为目前主要的移动源脱硝技术。传统铜基中孔分子筛高温水热稳定较差,而小孔分子筛负载催化材料具有优良的催化活性和水热稳定性,近年受到国内外研究者的广泛关注,成为一种新型NH₃-SCR催化材料。本文综述铜基小孔分子筛催化材料在柴油车尾气脱硝领域的研究进展。以Cu-SSZ-13和Cu-SAPO-34为例,论述其突出的低温活性和水热稳定性,总结Cu含量、Cu物种形态及表面酸性等因素对其催化活性、水热稳定性的影响,归纳其反应活性中心、反应路径等催化机理方面的研究进展。分析表明,该类催化材料是极具发展潜力的NH₃-SCR催化材料。其新型催化材料设计、抗中毒机理等还有待进一步深入研究。

Research Progress for Cu-based Small Pore Molecular Sieves as Disel De-NOx Catalysts

NO_x is one of the main pollutants in diesel vehicle emissions. Selective catalytic reduction of NO_x by ammonia (NH₃-SCR) has been extensively studied for the lean NO_x control due to its high performance and economic efficiency. Copper based zeolites have been widely used as the De-NO_x catalysts and significant research efforts have concentrated on developing different types of zeolites to improve the activity and durability. Recently, SCR catalysts based on small-pore molecular sieves have been reported for NH₃-SCR with much improved activities and high thermal durability and have received substantial attention. This review sums up the research progress related with Cu-based small pore molecular sieves, such as Cu-SSZ-13 and Cu-SAPO-34, as diesel De-NO_x Catalysts with outstanding low temperature NH₃-SCR activity and hydrothermal stability. The nature of the copper species and the surface acidity are the most important factors that affect the NH₃-SCR performance. Important results on the active sites and catalytic mechanisms are especially discussed in details. The possible developing orientations and research interests on the novel catalysts design and mechanisms of poisoning resistance are previewed.