Theoretical Study Addressing the (Meta-)Stability of Bimetallic Nanostructures

在理论研究的基础上，该项目将有助于更好地理解双金属纳米结构的稳定性和反应性。为了改变双金属催化剂的性质，可以改变其组成和/或结构。然而，催化活性的双金属结构往往不稳定，并表现出降解。如果不具有热稳定性，那么具有所需催化性能的最佳双金属结构也是无用的。催化活性结构不一定需要热力学稳定，它们也可能是动力学稳定的。因此，需要用非平衡法来检验静止结构的出现。因此，需要通过动力学蒙特卡罗(KMC)模拟来研究双金属纳米结构的稳定性。作为KMC模拟的必要输入的活化势垒应从基于密度泛函理论(DFT)的电子结构计算中得到。将重点放在经过充分实验研究的模型系统上，得出双金属表面合金稳定性的一般趋势。

Based on theoretical studies, this project shall lead to a better understanding of the stability and reactivity of bimetallic nanostructures. In order to alter the properties of bimetallic catalysts, the composition and/or the structure can be modified. However, catalytically active bimetallic structures are often not stable and exhibit degrading. The best bimetallic structure with desired catalytic properties is useless if it is not thermally stable. Catalytically active structures do not necessarily need to be thermodynamically stable, they might also be kinetically stabilized. Non-equilibrium methods are hence required to test of occurence of stationary structures. Therefore the stability of bimetallic nanostructures shall be studied by performing kinetic Monte Carlo (kMC) simulations. The activation barriers which are a necessary input for the kMC simulations shall be derived from electronic structure calculations based on density functional theory (DFT). Concentrating on experimentally well-studied model systems, general trends in the stability of bimetallic surface alloys shall be derived.