| AVS 65th International Symposium & Exhibition | |
| Fundamental Discoveries in Heterogeneous Catalysis Focus Topic | Thursday Sessions |
| Session HC+SS-ThM |
| Session: | In-situ Analysis of Heterogeneously Catalyzed Reactions |
| Presenter: | Kersti Hermansson, Dept of Chemistry-Ångström, Uppsala University, Sweden |
| Authors: | K. Hermansson, Dept of Chemistry-Ångström, Uppsala University, Sweden P. Mitev, Dept of Chemistry-Ångström, Uppsala University, Sweden J. Kullgren, Dept of Chemistry-Ångström, Uppsala University, Sweden P. Broqvist, Dept of Chemistry-Ångström, Uppsala University, Sweden |
| Correspondent: | Click to Email |
Redox-active metal oxide surfaces and interfaces ‒ such as electrodes, catalysts, and sensors ‒ play crucial roles in our society and in the development of new materials and greener technologies. In the scientific literature, a full arsenal of experimental methods are being used to help characterize such interfaces. At the same time, the number of theoretical studies in the literature steadily increases, providing mechanistic information at a detail that is hard to beat by experiment. Are such theoretical results accurate enough?
I will describe some of our efforts to develop multiscale modelling protocols for metal oxide surfaces and nanoparticles (e.g. of CeO2, ZnO and MgO). We combine a range of theoretical methods including DFT, tight-binding-DFT [1], and reactive force-field models A key question is whether it is really possible to model redox-active metal oxides without including the electrons?
The O2 chemistry of reducible oxides is rich and famous and I will therefore also discuss various aspects of how adsorbed oxygen on nanoparticles and clusters can stabilize in the form superoxide ions (O2–) and the implications that this may have on their reactivities. Microkinetic modelling results to mimic experimental TPD spectra will be presented as well as mechanistic detail that is currently only possible to obtain from modelling.
The H2O molecule deserves special attention as hydroxylation/hydration changes the properties and reactivities of metal oxides, often with far-reaching consequences. We recently studied a thick water film on a ZnO(10-10) surface using MD simulations from a neural-network-generated potential landscape of DFT quality combined with anharmonic vibrational frequency calculations.[2] and were able to relate H-bond structure and frequencies in a meaningful way. In an attempt to reach a step further in terms of understanding found that a parabola-like 'OH frequency vs. in-situ electric field' relation holds for both intact and dissociated water molecules on ionic surfaces [3], and for both thin and thick films (unpublished).
I will also inform about the European Materials Modelling Council (https://emmc.info/), which aims to promote the use of materials modelling in –not least– industry.
References:
[1] J. Kullgren et al., J. Phys. Chem. C 121, 4593−4607 (2017).
[2] V.Quaranta et al., J. Chem. Phys. 148, 241720 (2018).
[3] G. G. Kebede et al., Phys.Chem.Chem.Phys. 20, 12678 (2018)