First-principles approach to in-situ model catalyst studies

对明确定义的单晶模型催化剂进行原位研究的目的是将超高真空表面科学方法固有的严格的原子尺度理解转移到技术相关的近环境条件中。在相应的进料和通常更高的转化率下，气体表面系统的传热和传质限制变得越来越重要。在复杂的原位反应器几何结构中，这种流动效应需要仔细理解、控制，最好是解开它，以达到对正在进行的表面化学的分子水平的理解。在目前的项目中，我们建议通过推进基于第一性原理的多尺度建模方法来补充这些努力，该方法的范围从基本表面催化过程到宏观尺度流动剖面。通过将第一性原理动力学蒙特卡罗（1pkMC）微动力学描述集成到OpenFoam/CatalyticFoam计算流体动力学包中，我们特别希望生成公开可用的通用方法，可以在完全解析的原位反应器几何形状中明确描述反应-输运耦合。在材料间隙方面，方法将从单晶扩展到具有平面支撑的纳米颗粒的模型催化剂。对于这两股，我们期望比我们之前在理想化流动几何上的工作中所展示的更多和更复杂的转移限制。概念的探讨和发展将进一步缩小多相催化物理化学和化学工程研究之间的差距。此外，建立的1pkMC-flow框架将用于定量模拟CO在Pd（100）上氧化的原位x射线光电子能谱数据。

The purpose of in-situ studies of well-defined single-crystal model catalysts is to transport the rigorous atomic-scale understanding inherent to the ultra-high vacuum Surface Science approach to technologically relevant near-ambient conditions. In corresponding feeds and at typically much higher conversion rates heat and mass transfer limitations in the gas-surface system become increasingly important. Such flow effects in the complex in-situ reactor geometries need to be carefully understood, controlled and at best disentangled to reach the aspired molecular-level understanding of the on-going surface chemistry. In the present project we propose to complement these endeavors by advancing a first-principles based multiscale modeling approach that ranges from the elementary surface catalytic processes to the macro-scale flow profiles. By integrating first-principles kinetic Monte Carlo (1pkMC) microkinetic descriptions into the OpenFoam/CatalyticFoam computational fluid dynamics package we specifically want to generate publicly available general-purpose methodology that can explicitly describe the reaction-transport coupling in fully resolved in-situ reactor geometries. On the materials gap side the approach will be extended from single crystals towards model catalysts featuring nanoparticles on a planar support. For both strands we expect even more and intricate transfer limitations than demonstrated in our preceding work on idealized flow geometries. The conceptual discussion and development will further close the gap between physico-chemical and chemical-engineering type research in heterogeneous catalysis. In addition, the established 1pkMC-flow framework will be employed to quantitatively model in-situ X-ray photoelectron spectroscopy data for CO oxidation on Pd(100).