| AVS 65th International Symposium & Exhibition | |
| Fundamental Discoveries in Heterogeneous Catalysis Focus Topic | Wednesday Sessions |
| Session HC+SS-WeA |
| Session: | Theory and Dynamics of Heterogeneously Catalyzed Reactions |
| Presenter: | Henrik Grönbeck, Chalmers University of Technology, Gothenburg, Sweden |
| Correspondent: | Click to Email |
A major challenge in heterogeneous catalysis research is the determination of dominating reaction paths and kinetic bottlenecks. One reason for the challenge is the dynamic character of the kinetics, where the active sites may change with reaction conditions. Nevertheless, it is atomic scale information that allow for catalyst development beyond trial-and-error approaches. Kinetic modeling based on first principles calculations have over the past decade grown into an important tool for investigating the importance of different catalyst phases and reaction paths. In this contribution, I will discuss work where we have used density functional theory in combination with kinetic modeling to investigate catalytic reactions over metals, oxides and nanoparticles. The examples cover different aspects of kinetic modeling including determination of adsorbate entropies, importance of attractive adsorbate-adsorbate interactions and the complexity of many types of active sites.
Complete methane oxidation to carbon dioxide and water is used as one example and we have investigated the reaction over metallic Pd(100) and Pd(111) [1] as well as PdO(101) [2]. The reaction paths are shown to be markedly different on the metallic and the oxidized surfaces. We find that the catalytic activity is highly sensitive to adsorbate-adsorbate interactions which for PdO(101) are attractive owing to electronic pairing effects. This effect is crucial and common for oxide surfaces [3].
Reactions over platinum nanoparticles are investigated using a recently developed scaling relation Monte Carlo technique [4]. Taking CO oxidation as a model reaction, we find that the overall activity is determined by complex kinetic couplings. Effects of particle shape as well as internal and external strain will be discussed [5].
[1] M. Jørgensen, H. Grönbeck, ACS Catalysis, 6, 6730 (2016).
[2] M. Van den Bossche, H. Grönbeck, J. Am. Chem. Soc. 137, 37 (2015).
[3] M. Van den Bossche, H. Grönbeck, J. Phys. Chem. C 120, 8390 (2017).
[4] M. Jørgensen, H. Grönbeck, ACS Catalysis 7, 5054 (2017).
[5] M. Jørgensen, H. Grönbeck, Angew. Chem. Int Ed. (2018).