International Collaboration in Chemistry: First Principles Multi-Lattice Kinetic Monte Carlo Simulations of NOx Storage Reduction Catalysts

这项研究的广泛目标是对循环条件下运行的废气催化剂的表面反应化学有一个基本的了解。使用一种综合的理论方法，我们专门针对NOx的减少，特别强调了在NOx储存还原(NSR)催化剂系统运行期间，当反应器条件从氧化循环到还原循环时，表面氧化相的出现和破坏。在方法上，这需要特定于材料的、定量的、明显依赖于时间的模拟工具，这些工具可以在NSR周期的宏观时间尺度上跟踪系统的演变，同时考虑到原子尺度的场地异质性和演变表面的空间分布。为了满足这些具有挑战性的要求，我们将开发一种新的多尺度方法，依赖于多格子第一原理动力学蒙特卡罗(KMC)方法。作为代表性的例子，模拟将在PdO(101)/Pd(100)表面氧化物模型上进行，但将注意确保将多晶格第一原理KMC方法推广到可能发生相变并导致表面晶格结构随环境变量变化的其他系统。

The broad objective of the research is to gain a fundamental understanding of the surface reaction chemistry of exhaust catalysts operating under cycling conditions. Using an integrated theoretical approach we specifically target NOx abatement, with particular emphasis on the appearance and destruction of surface oxide phases as the reactor conditions cycle from oxidative to reductive during the operation of the NOx Storage Reduction (NSR) catalyst system. Methodologically this requires material-specific, quantitative and explicitly time-dependent simulation tools that can follow the evolution of the system over the macroscopic time-scales of NSR cycles, while simultaneously accounting for the atomic-scale site heterogeneity and spatial distributions at the evolving surface. To meet these challenging demands we will develop a novel multi-scale methodology relying on a multi-lattice first-principles kinetic Monte Carlo (kMC) approach. As representative example the simulations will be carried out on a PdO(101)/Pd(100) surface oxide model, but care will be taken to ensure a generalization of the multi-lattice first-principles kMC approach to other systems in which phase transformations may occur and result in a change in the surface lattice structure depending upon environmental variables.