Multiscale modelling of metal oxide interfaces and nanoparticles

• 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?  Here the major challenges are (i) how to build a structural model that captures the complexity and imperfections of the real system at hand, and (ii) how to find an interaction model/a materials relation (say a DFT functional [1] or a force-field) that is good enough.A 5 nm metal oxide nanoparticle may be very small to an experimentalist, but it contains many thousand atoms, making standard quantum-mechanical (e.g. regular DFT) methods totally unfeasible. Can force-field calculations be used instead? Well, mimicking the interactions and chemical properties without explicit electrons present is a formidable task, especially when the transfer of electrons is closely coupled to the material's functionality, as is the case for redox-active metal oxides. I will discuss some of our efforts in the development of a multiscale modelling approach for surfaces and interfaces of metal oxides (e.g. CeO2, ZnO, MgO) – with and without interacting molecules (e.g. O2 and water).In summary, we combine a range of theoretical methods including DFT [2], tight-binding-DFT [3], and reactive force-field simulations [4] in a consistent multi-scale approach to examine the properties of oxide nanosystems. We generate images and spectra to make direct comparisons with the experimental couterparts (e.g. IRRAS spectra [5] and a new unpublished approach to predict vibrational spectra for OH-covered metal oxides), but we also generate properties that cannot be measured by experiments such as the water dipole moment enhancement on a surface (oftem much larger than in liquid water!). I will also inform about the European Materials Modelling Council (https://emmc.info/), and our efforts to promote the use of materials modelling in industry and the quality of the modelling results; the EMMC is open to everyone interested.References:[1] G. G. Kebede, D. Spångberg, P. D. Mitev, P. Broqvist, K. Hermansson, "Comparing van der Waals DFT methods for water on NaCl(001) and MgO(001), The Journal of Chemical Physics 146, 064703 (2017). [2] M. Hellström, D. Spångberg, K. Hermansson, "Treatment of Delocalized Electron Transfer in Periodic and Embedded Cluster DFT Calculations: The Case of Cu on ZnO (10-10)", Journal of Computational Chemistry 36, 2394 (2015). [3] J. Kullgren, M. J. Wolf, K. Hermansson, Ch. Köhler, B. Aradi,Th. Frauenheim, and P. Broqvist, "Self-Consistent-Charge Density-Functional Tight-Binding (SCC-DFTB) Parameters for Ceria in 0D to 3D". J. Phys. Chem. C  121, 4593−4607 (2017). [4] P. Broqvist, J. Kullgren, M. J. Wolf, A. C. T. van Duin, K. Hermansson, "A ReaxFF force-field for ceria bulk, surfaces and nanoparticles", J. Phys. Chem. C 119, 13598 (2015). [5] S. Hu, Z. Wang, A. Mattsson, L. Österlund, K. Hermansson, "Simulation of IRRAS Spectra for Molecules on Oxide Surfaces: CO on TiO2(110)", J. Phys. Chem. C 119, 5403 (2015).

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

Publikations- och innehållstyp

vet (ämneskategori)

kon (ämneskategori)