Davide Sarpa, David D O'Regan, Vasilios Bakolas, Joanna Procelewska, Joerg Franke, Philipp Roedel, Marcus Wolf, Chris-Kriton Skylaris
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引用次数: 0
摘要
60多年来,二烷基二硫代磷酸锌(ZDDPs)一直是汽车工业中应用最广泛的抗磨添加剂,但生产出具有保护作用的摩擦膜的途径仍然难以实现。在这种情况下,密度泛函理论(DFT)可以用来研究zddp和材料表面之间的相互作用。我们使用DFT+U计算来检查块状赤铁矿的电子结构和三个相关的(0001)表面末端:Fe-O-Fe, O-Fe-Fe和HO-Fe-Fe。我们的研究结果表明,虽然Fe-O-Fe和HO-Fe-Fe
;板是绝缘的,但O- fe - fe端接板是金属的,这是由于O悬空键形成的表面态
;此外,我们发现ZDDP在Fe-O-Fe
;板上的结合更强,导致ZDDP的几何形状和原子电荷的变化。当绑定到其他表面时,观察到最小的变化
;我们对赤铁矿及其表面的电子结构及其与ZDDP的相互作用进行了深入的研究。这项工作的新见解提供了一条新的途径,可以用来理解金属表面上ZDDPs的分解途径。
Exploring the interactions of ZDDP additive with hematite surfaces: a DFT+Ustudy.
The class of zinc dialkyldithiophosphates (ZDDPs) has been the most widely used anti-wear additive class in the automotive industry for over 60 years, yet the pathway to the generation of the protective tribofilm remains elusive. In this context, density functional theory (DFT) can be utilized to investigate the interactions between ZDDPs and materials surfaces. We employed DFT+Ucalculations to examine the electronic structure of bulk hematite and three relevant (0001) surface terminations: Fe-O-Fe, O-Fe-Fe, and HO-Fe-Fe. Our results demonstrate that, while the Fe-O-Fe and HO-Fe-Fe slabs are insulating, the O-Fe-Fe terminated slab is metallic due to the formation of surface states from O dangling bonds. Additionally, we found that ZDDP binds more strongly on the Fe-O-Fe slab, leading to changes in ZDDP geometry and atomic charges. Minimal changes are observed when bound to the other surfaces. We have provided an in-depth study of the electronic structure of hematite and its surfaces, and their interaction with ZDDP. We include a detailed study of the first-principles Hubbard U and Hund J for Fe 3d orbitals in bulk hematite, finding a negligible self-consistency effect but a significant projector dependence. The new insights from this work provide a new path that can be used to understand the decomposition pathways of ZDDPs on metallic surfaces.
期刊介绍:
Journal of Physics: Condensed Matter covers the whole of condensed matter physics including soft condensed matter and nanostructures. Papers may report experimental, theoretical and simulation studies. Note that papers must contain fundamental condensed matter science: papers reporting methods of materials preparation or properties of materials without novel condensed matter content will not be accepted.