The simultaneous reduction of nitric oxide and soot in emissions from diesel engines
The simultaneous reduction of nitric oxide and soot in emissions from diesel engines
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DOI：
10.1016/j.carbon.2008.11.043
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发表时间：
2009-03
期刊：
影响因子：
10.9
通讯作者：
Markus Sander;A. Raj;Oliver Richard Inderwildi;M. Kraft;S. Kureti;H. Bockhorn
中科院分区：
文献类型：
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作者：
Markus Sander;A. Raj;Oliver Richard Inderwildi;M. Kraft;S. Kureti;H. Bockhorn
最近的研究表明，烟灰分子上的一氧化氮分解形成表面氮和氧。表面氮可以重新结合为气态 N2，而表面氧则以 CO 的形式从烟灰分子中解吸。利用密度泛函理论、过渡态理论和动力学蒙特卡罗 (kMC) 模拟研究了气态 NO 向 N2 的非催化转化。结果通过实验得到验证。探索了烟灰表面上 NO 转化为 N2 的机制。优化中间稳定物质的几何形状以及过渡态以识别不同的反应步骤。应用过渡态理论计算每个中间反应的正向和反向反应速率。使用当前速率和中间物质的 kMC 模拟演示了在烟灰表面将 NO 转化为 N2 的可行机制。还表明一部分 NO 被捕获在烟灰表面上，并且在反应过程中会增加并阻塞活性炭位点，从而抑制进一步的反应。通过在多尺度模型中结合不同的理论技术，我们能够准确地描述 NO 存在下烟灰的转化。
Recent studies demonstrate that the decomposition of nitric oxide on a soot molecule forms surface nitrogen and oxygen. The surface nitrogen can be recombined to gaseous N2while the surface oxygen desorbs from the soot molecule as CO. This non-catalytic conversion of gaseous NO into N2is investigated using density functional theory, transition state theory and a kinetic Monte-Carlo (kMC) simulation. The results are validated against experiments. A mechanism for the conversion of NO to N2on a soot surface is explored. The geometries of the intermediate stable species as well as the transition states were optimized to identify the different reaction steps. The forward and backward reaction rate of each intermediate reaction is calculated applying transition state theory. A kMC simulation using the current rates and intermediate species demonstrates feasible mechanisms for the conversion of NO to N2on a soot surface. It is also suggested that a portion of NO is trapped on the soot surface and this increases during the reaction and blocks the active carbon sites inhibiting further reactions. By combining different theoretical techniques in a multi-scale model, we are able to describe the conversion of soot in the presence of NO accurately.