摘要:
Described are catalysts effective to abate NOx, hydrocarbons, and carbon monoxide from a gasoline engine exhaust gas. Such catalysts include a substrate having a first and second material disposed thereon, the first material effective to catalyze selective catalytic reduction of nitrogen oxides in the presence of ammonia and the second material effective to abate hydrocarbons and carbon monoxide, the first material comprising a molecular sieve promoted with copper and/or iron in a low loading, the second material comprising at least one oxide of Ni, Fe, Mn, Co, and Cu on a support selected from oxides of Ce, Ce—Zr, Zr, Mn, Pr and combinations thereof. Also described are gasoline engine exhaust gas treatment systems and methods of treating exhaust gas from a gasoline engine.
摘要:
Described are exhaust gas treatment systems for treatment of a gasoline engine exhaust gas stream containing NOx, particulate matter, and sulfur. The exhaust gas treatment system comprises: one or more catalytic articles selected from a three-way conversion catalyst (TWC), a lean NOx trap (LNT), and an integrated LNT-TWC; a platinum-containing catalytic article downstream from the one or more catalytic articles; and one or more selective catalytic reduction (SCR) catalytic articles immediately downstream from the platinum-containing catalytic article, the one or more SCR catalytic articles including a molecular sieve. The system stabilizes the SCR catalytic article from poisoning by sulfur.
摘要:
Described is a selective catalytic reduction catalyst comprising a zeolitic framework material of silicon and aluminum atoms, wherein a fraction of the silicon atoms are isomorphously substituted with a tetravalent metal. The catalyst can include a promoter metal such that the catalyst effectively promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H20 selectively over a temperature range of 150 to 650 °C. In another aspect, described is a selective catalytic reduction composite comprising an SCR catalyst material and an ammonia storage material comprising a transition metal having an oxidation state of IV. The SCR catalyst material promotes the reaction of ammonia with nitrogen oxides to form nitrogen and H20 selectively over a temperature range of 150 °C to 600 °C, and the SCR catalyst material is effective to store ammonia at temperatures of 400 °C and above. A method for selectively reducing nitrogen oxides, and a method for simultaneously selectively reducing nitrogen oxide and storing ammonia are also described. Additionally, an exhaust gas treatment system is also described.
摘要翻译:描述了一种选择性催化还原催化剂,其包含硅和铝原子的沸石骨架材料,其中一部分硅原子被四价金属同晶取代。 催化剂可以包括助催化剂金属,使得催化剂有效地促进氨与氮氧化物的反应,以在150至650℃的温度范围内选择性地形成氮气和H 2 O. 另一方面,描述了选择性催化还原复合物,其包含SCR催化剂材料和包含具有IV氧化态的过渡金属的氨储存材料。 SCR催化剂材料促进氨与氮氧化物的反应以在150℃至600℃的温度范围内选择性地形成氮气和H 2 O,并且SCR催化剂材料在400℃以上的温度下有效地存储氨。 还描述了选择性还原氮氧化物的方法,以及同时选择性还原氮氧化物和储存氨的方法。 另外,还描述了排气处理系统。
摘要:
The present disclosure is directed to SCR catalysts, methods for their manufacture, and methods of treating emissions in an exhaust stream with them. The SCR catalysts are produced from pillaring and ion exchanging synthetic phyllosilicates, particularly hydrothermally synthesized phyllosilicates.