1. Support effect and reaction pathway for NO direct decomposition over CuMn/A (A=ZSM-5, Beta, SSZ-13) catalysts.
- Author
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Kang, Running, An, Sufeng, Wang, Xuehai, Wang, Gang, Chen, Hong, Zhang, Cuijuan, Bin, Feng, and Li, Yongdan
- Subjects
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CATALYSTS , *COPPER , *DIMERS , *ADSORPTION (Chemistry) , *OXIDATION-reduction reaction - Abstract
The CuMn/ZSM-5 (CM/Z), CuMn/Beta (CM/B), and CuMn/SSZ-13 (CM/S) catalyst samples were prepared via an excess impregnation method to investigate the metal-support effect. The results show that the activity at 550 °C for NO direct decomposition follows the order of CM/Z (53.4%) > CM/B (49.2%) > CM/S (7.9%). The good activity and stability of CM/Z are attributed to a strong support effect including forming more active copper sites of the (Cu2+-O2--Cu2+)2+ and (Cu+-□-Cu+)2+ dimers, which have higher redox activity, capacity of oxygen mobility, and NO sorption capability. The competitive adsorption between NO and O 2 on the oxygen vacancy of dimers over CM/Z results in the activity decrease from 53.4% to 40.3% at 550 °C after adding 1 vol% O 2. The reaction mechanism over CM/Z was discussed based on the in situ DRIFT and isotopic (18O 2) experiments. Two NO adsorbs firstly on (Cu+-□-Cu+)2+ to form N 2 O, and N 2 O is activated to produce N 2 , followed by the NO adsorption on (Cu2+-O2--Cu2+)2+ to form nitrite and nitrate species and decomposition to NO and O 2. [Display omitted] ● The support effect of ZSM-5, Beta, and SSZ-13 supported CuMn is examined. ● CuMn/ZSM-5 exhibits a high NO to N 2 conversion of 53.4% at 550 °C. ● The intermediate species and competitive adsorption of NO and O 2 are discussed. ● The reaction pathways for NO direct decomposition are proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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