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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >First-Principles Kinetic of CO Desorption from Oxygen Species on Carbonaceous Surface
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First-Principles Kinetic of CO Desorption from Oxygen Species on Carbonaceous Surface

机译：碳在表面上从氧气中解吸CO的第一性原理

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摘要

We present an ab initio direct dynamics study on the desorption of CO from semiquinone carbon-oxygen species in carbonaceous surfaces. Density functional theory, in particular B3LYP/6-31G(d) level, was used to calculate the potential energy surface information. We found that in the initial stage of the desorption process, the six-member ring of the carbonaceous model opens slightly to let the CO break away, and then closes up to form the five-member ring. Because of low-lying excited estates in the carbon-oxygen complexes, electronic crossing occurs from reactants to products. Transition-state structures were found for the groundstate path, and the activation desorption energy is in excellent agreement with existing experimental data. Transition-state theory was used to calculate the thermal rate constant for desorption of CO in the range of 600-1700 ℃. The fitted Arrhenius expression for the calculated rate constants is k(T) = 1.81 * 10~(17) exp[-47682/T(K)](s~(-1)), which is within the experimental uncertainty for char gasification. In summary, we demonstrate that it is possible to model kinetics of elementary reactions in carbonaceous surfaces.
机译：我们提出了一个从头开始的直接动力学研究，从含碳表面的半醌碳-氧物种中解吸一氧化碳。密度泛函理论，特别是B3LYP / 6-31G（d）能级，用于计算势能面信息。我们发现，在解吸过程的初始阶段，碳质模型的六元环略微打开以使CO脱离，然后闭合形成五元环。由于碳-氧络合物中的低激发态，因此从反应物到产物发生电子交叉。发现了基态路径的过渡态结构，其活化解吸能与现有实验数据非常吻合。采用过渡态理论计算了600-1700℃范围内CO脱附的热速率常数。计算出的速率常数的拟合Arrhenius表达式为k（T）= 1.81 * 10〜（17）exp [-47682 / T（K）]（s〜（-1）），在焦炭气化的实验不确定性范围内。总而言之，我们证明了可以对碳质表面中基本反应的动力学建模。

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