Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 10: Metal/Water Interfaces: Structure and Reactivity
O 10.13: Talk
Monday, March 16, 2015, 18:00–18:15, HE 101
First-principles reaction barriers for the splitting of water on Au nanocatalysts — •Thomas Stecher, Harald Oberhofer, and Karsten Reuter — Technische Universität München
First-principles modeling of electrocatalytic surface reactions is still largely defined by the computational hydrogen approach. This approach evaluates free energy differences between consecutive reaction steps and therewith accounts only for possibly existing thermodynamic barriers. In order to access additional kinetic barriers in the photocatalytic oxidation of water we present an approach based on ab initio molecular dynamics (AIMD) simulations and umbrella sampling. For the proton transfer steps we hereby specifically use path-integral AIMD to also capture nuclear quantum effects. As a first showcase system we consider water splitting at a Au3 co-catalyst, which was previously studied within the computational hydrogen electrode approach [1]. This allows to disentangle thermodynamic and kinetic contributions to the individual reaction barriers, as well as to assess the relevance of quantum effects by comparing classically and quantum-mechanically calculated barriers. [1] H. Oberhofer and K. Reuter, J. Chem. Phys. 139, 044710 (2013).