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Composite Cu-SSZ-13 and CeO2-SnO2 for enhanced NH3-SCR resistance towards hydrocarbon deactivation
Applied Catalysis B: Environment and Energy ( IF 22.1 ) Pub Date : 2020-09-08 , DOI: 10.1016/j.apcatb.2020.119536
Ferenc Martinovic , Fabio Alessandro Deorsola , Marco Armandi , Barbara Bonelli , Regina Palkovits , Samir Bensaid , Raffaele Pirone

The state-of-the-art Cu-SSZ-13 was mixed with CeO2-SnO2 to form a Composite catalyst which was resistant towards hydrocarbon poisoning of the NH3-mediated NOx-SCR reaction. The Composite was prepared via a solid-state synthesis through ball milling, which did not influence the final morphology. The resistance towards propylene poisoning was remarkably enhanced as the NOx conversion over the Composite catalyst decreased only 9% compared to 40 % over the unmodified Cu-SSZ-13. Transient and dynamic reactivity studies showed that the coke formed during the C3H6 protolytic polymerization was dispersed inside the zeolite pores and the addition of CeO2-SnO2 did not prevent its formation nor enhance its oxidation with O2. The ion-exchanged Cu was the principal active component for the coke and hydrocarbon oxidation and the hydrocarbon poisoning prevention was attributed to the complex interaction between the three primary active sites (Cu – CeO2-SnO2 – protonic sites). Propylene oxidation over Cu-SSZ-13 was inhibited when NO was included in the reaction stream, while over the H-Composite (mixture of H-SSZ-13 and CeO2-SnO2) it had the reverse effect, since C3H6 and NOx oxidation did not compete for the same active sites on CeO2-SnO2. Basing on reactivity studies coupled with IR analysis, a deactivation and poisoning prevention mechanism was proposed, whereby the HONO/nitrate intermediates formed over the CeO2-SnO2 catalyst re-activated the zeolitic copper for the SCR reaction.



中文翻译:

复合Cu-SSZ-13和CeO 2 -SnO 2可增强NH 3 -SCR的抗烃失活性

将最新的Cu-SSZ-13与CeO 2 -SnO 2混合以形成复合催化剂,该复合催化剂可抵抗NH 3介导的NO x -SCR反应的烃中毒。复合材料是通过球磨的固态合成方法制备的,不影响最终的形貌。对丙烯中毒的抗性显着提高作为NO X转化率超过相比在未修饰的Cu-SSZ-13的40%的复合催化剂仅降低9%。瞬态和动态反应性研究表明,在C 3 H 6质子聚合过程中形成的焦炭分散在沸石孔内,并添加了CeO2 -SnO 2既不阻止其形成也不增强其与O 2的氧化。离子交换的铜是焦炭和碳氢化合物氧化的主要活性成分,防止碳氢化合物中毒的原因是三个主要活性部位(Cu – CeO 2 -SnO 2 –质子部位)之间复杂的相互作用。当反应流中包含NO时,Cu-SSZ-13上的丙烯氧化受到抑制,而在H-复合材料(H-SSZ-13和CeO 2 -SnO 2的混合物)上,丙烯氧化则具有相反的作用,因为C 3 H 6和NO x氧化不竞争CeO 2上的相同活性位-SnO 2。基于反应性研究和红外分析,提出了一种失活和防止中毒的机理,从而在CeO 2 -SnO 2催化剂上形成的HONO /硝酸盐中间体将沸石铜重新活化以进行SCR反应。

更新日期:2020-09-20
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