氧气空位诱导的协调变化对Pd/CeO2对NO减量的影响
Houlin Wang1, Chuan Gao1, Rong Wang1
1State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
Environmental science & technology
|January 18, 2024
概括
催化剂的特性,如氧空缺和协调作用,影响环境催化中的副产品形成. 了解这些因素是控制NO减少过程中N2O和NH3生成的关键.
科学领域:
- 环境催化剂环境催化剂
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
背景情况:
- 环境催化中的副产品形成受到催化剂化学状态和协调的显著影响.
- 在 (CeO2) 上支持的 (Pd) 是广泛使用的催化剂,但它们的副产品形成机制需要更深入的研究.
研究的目的:
- 为了研究N2O和NH3的形成机制,在CO降低NO超过Pd/CeO2催化剂.
- 阐明氧空位 (Ov) 和Pd协调号 (CN) 在副产品选择性中的作用.
主要方法:
- 合成两种具有不同Ov和CN的Pd/CeO2催化剂 (PdCe-350和PdCe-800).
- 在干燥和潮湿条件下进行现场光谱研究.
- 对副产品形成路径 (N2O和NH3) 的分析.
主要成果:
- 具有较高Ov和CN的PdCe-350显示出增强的金属支相互作用和增加的副产品形成.
- 低温下N2O形成与Ov密度 (化酸物种) 和高温下Pd反应性 (单酸) 相相关.
- NH3的形成与H2O和C3H6的激活有关,其中低酸盐是关键的中间体.
结论:
- 催化剂的局部协调和表面氧气空缺极大地影响了NO减排中的副产品分布.
- 了解这些关系为设计高效的环境催化剂提供了基本的见解.
- 定制Ov和Pd CN提供了一种控制N2O和NH3选择性的途径.
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