Posysaev Sergei, Alatalo Matti
Nano and Molecular Systems Research Unit, University of Oulu, PO Box 3000, Oulu FI-90014, Finland.
ACS Omega. 2019 Feb 22;4(2):4023-4028. doi: 10.1021/acsomega.8b02990. eCollection 2019 Feb 28.
We have performed a density functional theory study of the MoS monolayer and the MoS (100) and (103) surfaces in relation to the early stages of the hydrodesulfurization reaction. In many X-ray diffraction (XRD) results, the (103) surface exhibits a higher peak than the (100) surface, yet one of the most frequently occurring surface has not been studied extensively. By analyzing experimental studies, we conclude that the (103) surface of MoS is the most frequently occurring edge surface when the sample size is thicker than ∼10-15 nm. Herein, we report the first comparison of reaction paths for the formation of a sulfur vacancy on the (103) surface of MoS, monolayer, and (100) surface of MoS. The reason for the occurence of the (103) surface in the XRD patterns has been established. We point out the similarity in the reaction barriers for the monolayer and (100) and (103) surfaces and discuss the reason for it. Moreover, we found a more energetically favorable step in the reaction pathway for the formation of a sulfur vacancy, which allowed us to refine the previously established pathway.
我们对二硫化钼单层以及二硫化钼（100）和（103）表面进行了密度泛函理论研究，该研究与加氢脱硫反应的早期阶段相关。在许多X射线衍射（XRD）结果中，（103）表面显示出比（100）表面更高的峰，但最常出现的表面之一尚未得到广泛研究。通过分析实验研究，我们得出结论，当样品厚度大于约10 - 15纳米时，二硫化钼的（103）表面是最常出现的边缘表面。在此，我们报告了首次对二硫化钼（103）表面、单层二硫化钼以及二硫化钼（100）表面上硫空位形成的反应路径进行的比较。已经确定了XRD图谱中（103）表面出现的原因。我们指出了单层以及（100）和（103）表面反应势垒的相似性并讨论了其原因。此外，我们在硫空位形成的反应途径中发现了一个能量上更有利的步骤，这使我们能够完善先前确定的途径。
