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O: Fachverband Oberflächenphysik
O 10: Metal/Water Interfaces: Structure and Reactivity
O 10.11: Vortrag
Montag, 16. März 2015, 17:30–17:45, HE 101
Solvent Effects in Co-Catalyzed Oxygen Evolution: Efficient First-Principles Treatment — •Markus Sinstein1, Harald Oberhofer1, Volker Blum2, and Karsten Reuter1 — 1Technische Universität München, Germany — 2Duke University, USA
Photoelectrochemically driven redox reactions like water splitting or CO2 reduction are prominent examples for energy-conversion from abundant sunlight into solar-fuel type chemical compounds. A detailed analysis of the involved elementary processes via first-principles calculations requires to simultaneously account for the extended semiconductor photocatalyst and the liquid electrolyte. Beyond traditionally assumed proton-coupled electron transfer (PCET) mechanisms the latter is particularly important in order to address charged reaction intermediates that are likely stabilized by the polar liquid environment. Aiming for a computationally efficient approach that allows for catalyst screening, we implement an implicit solvation scheme based on the Multipole Expansion (MPE) method into the all-electron DFT package FHI-aims. We define the cavity within the dielectric continuum from an iso-density surface which is sampled in a constraint dynamics scheme. As a first step towards modelling the full water splitting reaction, we apply this scheme to the oxygen evolution reaction on gold co-catalysts. These calculations indicate non-negligible solvent effects already for neutral intermediates in PCET mechanisms.