Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 60: Chemistry at Solid/Liquid Interfaces

O 60.10: Vortrag

Mittwoch, 9. März 2016, 17:30–17:45, S052

Electro-oxidation of methanol from first-principles with an implicit solvation method — •Sung Sakong and Axel Groß — Institut für Theoretische Chemie, Universität Ulm, 89069 Ulm, Germany

The methanol electro-oxidation is the central reaction in the direct methanol fuel cell (DMFC). We present a first-principles computational studies addressing the reaction mechanism occuring on the anode of the DMFC based on density functional theory (DFT). The electrode-electrolyte interface is modeled by a Pt(111) slab in an implicit solvent [J. Chem. Phys. 142, 234107 (2015)]. The electrode potential of the electrochemical cell is parametrized using the computational hydrogen electrode method. Thus DFT calculations yield the energetics of reaction intermediates on the Pt electrode as a function of the electrode potential U. We find that the presence of the implicit solvent leads to subtle changes in the relative energies of the reaction intermediates. Based on calculated activation barriers, a possible reaction scheme is proposed. We will demonstrate that the total oxidation of methanol is possible at electrode potentials of U>0.6 V on Pt(111), in agreement with experimental observations. Based on the proposed reaction scheme, we will discuss possible scenarios to improve the performance in the methanol electro-oxidation.