铁和二维磷烯表面吸附的第一性原理研究

发布时间：2018-06-12 02:19

本文选题：Fe(111)面 + 表面吸附　；参考：《吉林大学》2017年硕士论文

【摘要】：表面吸附是表面催化、摩擦学、储氢、电化学、传感器等领域的重要科学研究问题。铁(Fe)具有很广泛的应用,如在电化学、腐蚀和催化等领域。Fe表面防腐是一项重大的研究课题。表面吸附小分子是导致Fe表面发生腐蚀的一种重要原因,因此,研究分子气体在Fe表面的吸附行为是很有必要的。另外,对于二维材料黑磷,由于其具有直接带隙,使其在导电性能的实际应用中受到一定的限制。原子吸附能够改善磷烯材料的性能,进而扩展磷烯材料在各领域的应用。因此,表面原子吸附是提高工程材料性能的一种重要调制方法。本文采用密度泛函理论(DFT)方法,具体研究内容如下:采用DFT研究了气相条件下不同分子(O_2、H_2O、CO_2、H_2、N_2、CO、He)分别在Fe(111)和含C的Fe(111)表面的吸附特性。结果表明不同分子在Fe(111)面吸附的顺序为O_2C_ON_2H_2CO_2H_2OHe,且Fe(111)对除了He以外的其他气体分子都具有高活性。相比于Fe(111)面,C增强了Fe(111)表面吸附H2的能力,降低了Fe(111)表面吸附其它分子的能力。气体如具有闭壳层电子结构的CO_2和N_2,它们在Fe(111)上的吸附很强,表明γ-Fe可作为高效的催化剂来催化与它们有关的反应。然而,就保护γ-Fe而言,我们不仅要排除活泼气体(O_2和H_2O),也要排除常用的保护气体(CO_2和N2)。采用DFT研究了双层磷烯及其夹层中吸附稀有气体(Xe、Kr、Ar)的几何结构和电子结构。结果表明稀有气体的吸附导致双层磷烯结构发生变形,使其电子结构发生改变。在双层磷烯夹层之间吸附6个Xe、Kr或Ar原子时,相应体系由原来的直接带隙变为间接带隙,且在导带底处的电子有效质量变化趋势为me(Xe)me(Ar)me(Kr),因此电子载流子迁移率大小顺序为μ(Xe)μ(Ar)μ(Kr)。原子吸附改变了双层磷烯的导电性,这有助于研究人员了解双层磷烯的电子传导性能的几何结构依赖性。
[Abstract]:Surface adsorption is an important scientific research in the fields of surface catalysis, tribology, hydrogen storage, electrochemistry, sensors and so on. Fe) has been widely used in many fields, such as electrochemistry, corrosion and catalysis. Surface adsorption of small molecules is an important cause of corrosion on Fe surface. Therefore, it is necessary to study the adsorption behavior of molecular gas on Fe surface. In addition, due to its direct band gap, black phosphorus is limited in the practical application of electrical conductivity. Atomic adsorption can improve the properties of phosphoenes and expand their applications in various fields. Therefore, surface atomic adsorption is an important modulation method to improve the properties of engineering materials. In this paper, the density functional theory (DFT) method is used to study the adsorption properties of different molecules O _ 2H _ 2O _ 2C _ 2C _ 2C _ 2O _ 2H _ 2H _ 2H _ 2C _ (1) on the surface of Fei _ (111) and C ~ (-containing) respectively by using the DFT method. The results show that the order of adsorption of the different molecules on the Feo 111) surface is O _ s _ 2C _ s _ 2H _ 2CO _ 2H _ 2O _ Heand) and the Fei _ (111) has high activity to the other gas molecules except he. Compared with the Fe _ (111) C, the adsorption capacity of H _ 2 on the surface of Fe _ (111) was enhanced, and the ability of the surface of Fe _ (111) to adsorb other molecules was decreased. The adsorption of gases such as COSP _ 2 and N _ 2s with closed shell electronic structure on Fei _ (111) is very strong, indicating that 纬 -Fe can be used as an efficient catalyst to catalyze the reactions related to them. However, as far as protecting 纬 -Fe is concerned, we should not only exclude the active gas O\ +\ {2}\ +\ {2\}\ {2\}\ {2\}\%\ {\}\ The geometrical and electronic structures of the adsorbed rare-gas Xekr Aran in the bilayer phosphorene and its intercalation were studied by DFT. The results show that the adsorption of rare gas results in the deformation of the structure of bilayer phosphorene and the change of its electronic structure. When six Xeo Kr or ar atoms are adsorbed between two layers of phosphene intercalation, the corresponding system changes from the original direct band gap to the indirect band gap, and the change trend of the electron effective mass at the bottom of the conduction band is that the electron carrier mobility is in the order of 渭 Xe) 渭 ar) 渭 Kr. Atomic adsorption changes the electrical conductivity of bilayer phosphorene, which helps the researchers to understand the geometric structure dependence of the electron conduction properties of bilayer phosphorene.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.3

【相似文献】