A comparative DFT study on CO oxidation reaction over Si-doped BC 2 N nanosheet and nanotube
A comparative DFT study on CO oxidation reaction over Si-doped BC 2 N nanosheet and nanotube
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DOI：
10.1016/j.apsusc.2017.12.254
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发表时间：
2018-05
影响因子：
6.7
通讯作者：
P. Nematollahi;E. Neyts
中科院分区：
文献类型：
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作者：
P. Nematollahi;E. Neyts
在本研究中，我们进行了密度泛函理论（DFT）计算，研究了Si原子嵌入缺陷BC2N纳米结构催化CO氧化的不同反应机制，并分析了结构和电子性质。所有配合物的结构均通过M062X/6-31G*计算级别的频率计算进行了优化和表征。此外，还详细研究了硅掺杂 BC2N 纳米结构上吸附的 CO 和 O2 分子的电子结构和热力学参数。此外，为了研究曲率对 CO 氧化反应的影响，还研究了有限尺寸扶手椅 (6,6) Si-BC2NNT 上的所有吸附和 CO 氧化反应。我们的结果表明，CO 与 O2 分子的氧化可能有两种可能的途径：O2(g)+CO(g)→O2(ads)+CO(ads)→CO2(g)+O(ads)和 O(ads)+CO(g)→CO2(g)。第一个反应通过 Langmuir-Hinshelwood (LH) 机制进行，而第二个反应通过 Eley-Rideal (ER) 机制进行。另一方面，通过增加管直径，由于O2分子的强吸附能（与其在管表面的解离有关），能量势垒增加。我们的计算表明，Si-BC2NNS 氧化反应的两步能垒小于 Si-BC2NNT。因此，Si-BC2NNS 可以作为 CO 氧化的有效且高度活化的底物，而不是 (4,4) Si-BC2NNT。
In this study, we performed density functional theory (DFT) calculations to investigate different reaction mechanisms of CO oxidation catalyzed by the Si atom embedded defective BC2N nanostructures as well as the analysis of the structural and electronic properties. The structures of all the complexes are optimized and characterized by frequency calculations at the M062X/6-31G∗ computational level. Also, The electronic structures and thermodynamic parameters of adsorbed CO and O2molecules over Si-doped BC2N nanostructures are examined in detail. Moreover, to investigate the curvature effect on the CO oxidation reaction, all the adsorption and CO oxidation reactions on a finite-sized armchair (6,6) Si-BC2NNT are also studied. Our results indicate that there can be two possible pathways for the CO oxidation with O2molecule: O2(g)+ CO(g)→ O2(ads)+ CO(ads)→ CO2(g)+ O(ads)and O(ads)+ CO(g)→ CO2(g). The first reaction proceeds via the Langmuir-Hinshelwood (LH) mechanism while the second goes through the Eley–Rideal (ER) mechanism. On the other hand, by increasing the tube diameter, the energy barrier increases due to the strong adsorption energy of the O2molecule which is related to its dissociation over the tube surface. Our calculations indicate that the two step energy barrier of the oxidation reaction over Si-BC2NNS is less than that over the Si-BC2NNT. Hence, Si-BC2NNS may serve as an efficient and highly activated substrate to CO oxidation rather than (4,4) Si-BC2NNT.