Cu-exchanged Al-rich OFF-CHA twin-crystal zeolite for the selective catalytic reduction of NOx by NH3
| Autor: | Xiaohan Wang, Yalian Bi, Qingling Liu, Shuangchun Lu, Xuebin Lu, Mingyu Guo, Zhenguo Li, Chunfeng Song, Degang Ma, Han Jinfeng, Caixia Liu, Na Ji |
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| Rok vydání: | 2021 |
| Předmět: |
Diesel exhaust
Chemistry chemistry.chemical_element Selective catalytic reduction 02 engineering and technology General Chemistry Atmospheric temperature range 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Copper Catalysis Hydrothermal circulation 0104 chemical sciences 0210 nano-technology Zeolite NOx Nuclear chemistry |
| Zdroj: | Catalysis Today. 376:87-94 |
| ISSN: | 0920-5861 |
| DOI: | 10.1016/j.cattod.2020.07.082 |
| Popis: | Novel Al-rich OFF-CHA twin-crystal zeolite was synthesized by one-pot hydrothermal method, and applied in ammonia-selective catalytic reduction (NH3-SCR) after copper ion exchange. Results indicated that Cu content in Cu-OFF-CHA played a significant role in NH3-SCR reaction. The insufficiency of copper activity sites and the formation of CuOx were the main reasons affecting low and high temperature SCR activity of catalyst, respectively. Cu3.1-OFF-CHA, with the optimal copper content, demonstrated over 90 % NOx conversion and exhibited excellent N2 selectivity in the range from 160 to 550 ℃. Further research verified that the SCR activity of Cu3.1-OFF-CHA maintained above 80 % in the temperature range from 180–450 °C after hydrothermal treatment 16 h. The reason might be that Cu2+ in Cu-OFF-CHA was migrated from CHA to OFF sites after hydrothermal treatment, and Cu2+ in OFF sites on Cu-OFF-CHA was more stable, resulting in less conversion of the active site to CuOx clusters. Cu-OFF-CHA has the potential to be applied in SCR after-treatment systems of diesel exhaust due to the excellent SCR activity and hydrothermal stability. |
| Databáze: | OpenAIRE |
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