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 invention relates to a process for the preparation of a zeolitic material having a CHA-type framework structure comprising YO2 and X2O3, wherein said process comprises the steps of: (1) providing a mixture comprising one or more sources for YO2, one or more sources for X2O3, one or more optionally substituted ethyltrimethylammonium cation-containing compounds, and one or more tetraalkylammonium cation R1R2R3R4N+-containing compounds as structure directing agent; (2) crystallizing the mixture obtained in step (1) for obtaining a zeolitic material having a CHA-type framework structure; wherein Y is a tetravalent element and X is a trivalent element, wherein R1, R2, and R3 independently from one another stand for alkyl, wherein R4 stands for cycloalkyl, and wherein the YO2:X2O3 molar ratio of the mixture in (1) ranges from 2 to 1,000, as well as to zeolitic materials which may be obtained according to the inventive process and to their use.