催化剂的内在选择性和结构敏感性对于C2+氧化物生产
Nuoya Yang1, Andrew J Medford2,3, Xinyan Liu2,3
1Department of Materials Science and Engineering, Stanford University , 496 Lomita Mall, Stanford, California 94305, United States.
催化剂将合成气转化为燃料. 这项研究显示,Rh{11}表面有利于乙化物,而Rh{21}有利于甲,铁杂质增加了乙醇的产生.
科学领域:
- 催化科学与工程
- 表面科学
- 计算化学
背景情况:
- 合成气体转化是从煤炭,天然气和生物质中生产液体燃料的关键.
- 是一种独特的元素催化剂,对乙醇和C2+氧化物具有选择性,但其反应机制仍有争议.
- 了解的催化行为对于开发高效的合成燃料至关重要.
研究的目的:
- 在Rh{211) 和Rh{111) 表面上开发CO+H2转换的微动力模型.
- 研究氧化物生产中的催化剂的结构敏感性和内在选择性.
- 阐明铁杂质在调节催化合成气转换中的作用.
主要方法:
- 使用BEEF-vdW函数进行密度函数理论 (DFT) 计算.
- 开发一个包含吸附物相互作用和DFT衍生的速率的平均场运动模型.
- 合成和表征Rh/SiO2催化剂,然后对氧化物产生进行催化试验.
主要成果:
- 表面Rh{21}显著更活跃,但对甲有选择性,而Rh{11}对乙有内在的选择性.
- 实验结果证实了Rh{11}对乙的选择性,并且显示了活性与氧化物选择性之间的反向相关性.
- 铁杂质在提高Rh/SiO2催化剂的乙醇选择性方面发挥了关键作用.
结论:
- 实验结果与有关催化剂结构敏感性的理论预测一致.
- 这项工作提供了关于合成气转换机制,活性位点和选择性的原子尺度见解.
- 这些发现可以指导合金催化剂的合理设计,使用更多的元素来生产合成燃料.
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