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Energy conversion at interfaces is at the centre of the rapidly growing field of basic energy science. This concerns desired conversions like solar to chemical energy, but also unavoidable by-products like the dissipation of chemical energy into heat. Particularly for highly exothermic catalytic reactions the latter is a crucial factor that needs to be well controlled in order to achieve optimum performance, durability and safety. While effective engineering approaches to account for the released heat at the continuum level are well established, quantitative first-principles based multiscale modelling that treats such effects is only just emerging. The indispensable basis for such a predictive quality-modelling is first-principles electronic structure theory. For a comprehensive understanding of the surface catalytic function this basis needs to be linked to more coarse-grained approaches that allow following the interplay of the on-going reactions over sufficiently long time spans. First-principles kinetic Monte Carlo (1p-kMC) simulations represent at present the only such approach that can evolve the full system dynamics from picoseconds up to seconds, while fully accounting for the correlations, fluctuations and spatial distributions of the chemicals at the catalyst surface. In this talk I will present our recent efforts to augment such first-principles multiscale descriptions with an appropriate account of energy dissipation. To one end this concerns the integration of 1p-kMC simulations into a fluid dynamical treatment of the macroscale flow structures in the reactor (1,2). To also capture potential atomistic consequences of the reaction heat on the elementary process dynamics we develop a novel QM/Me embedding approach for metal substrates, which enables proper dissipation into a classically described heat bath while simultaneously achieving an accurate description of the metal band structure.
References (1) Matera, S.; and Reuter, K. Catal. Lett. 2009, 133, 156. (2) Matera, S.; and Reuter, K. Phys. Rev. B, 2010, 82, 085446. |
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