周期密度函数理论研究甲激活在La(2)O(3) 上:O(2-),O(-),O(2)(2-),氧点缺陷和Sr(2+) 杂的表面位点的活性
Michael S Palmer1, Matthew Neurock, Michael M Olken
1Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22903, USA.
Journal of the American Chemical Society
|July 11, 2002
概括
在La(2)O(3)(001) 上的阳离子O ((s) ((-) 位点对甲激活最为活跃. 使用的兴奋剂会产生类似的活性位点,这表明甲具有氧化合的潜力.
科学领域:
- 表面化学 表面化学
- 催化剂是一种催化剂.
- 材料科学 材料科学 材料科学
背景情况:
- 兰氧化物 (La(2) O(3)) 是一种用于催化应用的有前途的材料.
- 了解甲激活的活性点对于开发高效的催化剂至关重要.
- 点缺陷和补充剂显著影响表面反应性.
研究的目的:
- 在La(2)O(3)(001) 上的各种表面地点研究从甲中提取气.
- 为了比较阳离子氧 (O(s) ((-)),过氧化物 (O(2(s)) ((2-)) 和兴奋剂部位的活性.
- 阐明甲激活的机制和氧化合的潜在途径.
主要方法:
- 渐变校正的周期密度函数理论 (DFT) 计算.
- 从甲中抽取的建模.
- 对反应能,激活障碍和结合能进行分析.
主要成果:
- 阳离子O (((s) ((-) 表面部位表现出甲激活的最高活性,激活障碍较低 (10.1 kcal/mol).
- 兴奋剂 (Sr(2+) /La(3+)) 产生与O(s) ((-)) 相似的活动的表面位点.
- 表面过氧化物 (O(2(s)) ((2-)) 位点对H抽象不那么有利,相比于O(s) ((-).
结论:
- 阳离子氧空缺是La(2)O(3)(001) 上甲激活的主要活性位点.
- 兴奋剂提供了一种可行的策略,用于设计催化剂的活性位点.
- 表面过氧化物可能在甲的氧化合中发挥作用,La(2)O(3)(001).
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