Xu S C, Irle S, Musaev D G, Lin M C
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
J Phys Chem B. 2006 Oct 26;110(42):21135-44. doi: 10.1021/jp0642037.
We present predictions of reaction rate constants for dissociative adsorption reactions of CO(x) (x = 1, 2) and NO(x) (x = 1, 2) molecules on the basal graphite (0001) surface based on potential energy surfaces (PES) obtained by the integrated ONIOM(B3LYP:DFTB-D) quantum chemical hybrid approach with dispersion-augmented density functional tight binding (DFTB-D) as low level method. Following an a priori methodology developed in a previous investigation of water dissociative adsorption reactions on graphite, we used a C(94)H(24) dicircumcoronene graphene slab as model system for the graphite surface in finite-size molecular structure investigations, and single adsorbate molecules reacting with the pristine graphene sheet. By employing the ONIOM PES information in RRKM theory we predict reaction rate constants in the temperature range between 1,000 and 5,000 K. We find that among CO(x) and NO(x) adsorbate species, the dissociative adsorption reactions of CO(2) and both radical species NO and NO(2) are likely candidates as a cause for high temperature oxidation and erosion of graphite (0001) surfaces, whereas reaction with CO is not likely to lead to long-lived surface defects. High temperature quantum chemical molecular dynamics simulations (QM/MD) at T = 5,000 K using on-the-fly DFTB-D energies and gradients confirm the results of our PES study.
我们基于通过集成ONIOM(B3LYP:DFTB-D)量子化学混合方法获得的势能面（PES），以色散增强密度泛函紧束缚（DFTB-D）作为低水平方法，给出了CO(x)（x = 1, 2）和NO(x)（x = 1, 2）分子在石墨基底（0001）表面上的解离吸附反应速率常数的预测。遵循先前对石墨上水的解离吸附反应研究中开发的先验方法，我们使用C(94)H(24)双环冠烯石墨烯平板作为有限尺寸分子结构研究中石墨表面的模型系统，以及单个吸附质分子与原始石墨烯片反应。通过在RRKM理论中采用ONIOM PES信息，我们预测了1000至5000 K温度范围内的反应速率常数。我们发现，在CO(x)和NO(x)吸附质物种中，CO(2)以及自由基物种NO和NO(2)的解离吸附反应很可能是导致石墨（0001）表面高温氧化和侵蚀的原因，而与CO的反应不太可能导致长期存在的表面缺陷。使用即时DFTB-D能量和梯度在T = 5000 K下进行的高温量子化学分子动力学模拟（QM/MD）证实了我们PES研究的结果。
