对NH3辅助的选择性降低CeO2上的NO的机制性见解:关于选择性和活性的第一原则微动力学研究
Danfeng Xiong1, Yang Chen1, Haiyang Yuan1,2
1Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis and Center for Computational Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China. hyyuan@ecust.edu.cn.
该研究揭示了用NH3 (NH3-SCR) 选择性催化降低NO的关键步骤,而不是CeO2催化剂. 在CeO2上空缺的氧气对于N2的选择性至关重要,而增强NH3吸附会增加活性.
科学领域:
- 材料科学 材料科学 材料科学
- 催化剂是一种催化剂.
- 表面化学 表面化学
背景情况:
- 用NH3 (NH3-SCR) 选择性催化降解NO,对于控制NOx排放至关重要.
- 基于CeO2的氧化物是NH3-SCR的有希望的催化剂,但它们的活性和选择性机制需要详细了解.
研究的目的:
- 阐明NH3-SCR在CeO2上的分子水平机制.
- 确定N2形成的活动和选择性限制因素.
- 为设计改进的基于CeO2的NH3-SCR催化剂提供理论指导.
主要方法:
- 第一个原则是对CeO2的微动力学研究{110}表面.
- 详细分析反应路径和过渡状态.
- 定量运动模拟和灵敏度分析.
主要成果:
- 确定了一种有利于N2形成的途径,涉及NH3解离,NH2与NO合,随后脱.
- 发现NHNO转移到氧空位 (Ovac) 是N2选择性决定的步骤.
- 确定NH2NO形成是总体NH3-SCR活动的速度决定性步骤.
结论:
- 在CeO2上空缺的氧气在增强N2选择性方面起着至关重要的作用.
- 增强NH3吸附是改善CeO2对NH3-SCR的催化活性的一个关键策略.
- 创建Ovac并结合具有强NH3吸附性的组件 (例如,WO3) 可以优化基于CeO2的催化剂以获得卓越的性能.
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