在部分氧化银催化剂上扩大乙烯氧化反应网络
Adhika Setiawan1, Tiancheng Pu1, Israel E Wachs1
1Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
ACS catalysis
|December 12, 2024
概括
一个新的微动力学模型解释了氧化乙烯的选择性. 该模型显示,虽然氧金属循环途径有利于燃烧,但二原子氧物种是乙烯氧化物生产的关键.
科学领域:
- 化学工程是化学工程的重要组成部分.
- 表面科学是一门学科.
- 催化剂是一种催化剂.
背景情况:
- 选择性氧化乙烯到乙烯氧化物 (EO) 对于化学生产至关重要.
- 在反应条件下了解银催化剂表面行为是提高EO选择性的关键.
- 最近的操作研究表明,银表面上有显著的氧气覆盖.
研究的目的:
- 为乙烯选择性氧化开发一个扩展的微动力学模型 (MKM).
- 为了研究氧化银表面表征上的反应路径 (p(4 × 4) Ag(111)).
- 阐明不同氧物种和表面相在EO生产中的作用.
主要方法:
- 开发了一个扩展的微动力学模型 (MKM),其中包含了三种EO和CO2生产途径.
- 使用了一组复合的实验和DFT动力参数,用实验数据进行优化.
- 采用多启动组合方法进行彻底的解决方案空间采样.
主要成果:
- 氧金属循环 (OMC) 途径本身不足以解释观察到的EO选择性,有利于二氧化碳的产生.
- 二原子氧物种 (O2/O*) 在乙烯氧化物形成的主要途径中起着关键作用.
- 该模型强调了银催化剂表面的动态性质,具有波动的金属/氧化相比例.
结论:
- 开发的MKM准确地反映了实验数据,并提供了对乙烯选择性氧化机制的见解.
- O2/O* 种类对于实现高乙烯氧化物选择性至关重要.
- 催化剂表面动力学显著影响反应动力学和产品分布.
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