Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 78: Surface chemical reactions

O 78.5: Vortrag

Donnerstag, 17. März 2011, 16:00–16:15, WIL B122

Theoretical elucidation of the competitive electro-oxidation mechanisms of Formic Acid on Pt(111) — •Wang Gao, John A. Keith, Josef Anton, and Timo Jacob — Institut für Elektrochemie, Universität Ulm, Albert-Einstein-Allee 47, D-89069 Ulm, Germany

The mechanisms of formic acid (HCOOH) oxidation on Pt(111) under electrochemical conditions have been studied using density functional theory, itself an very important reaction in energy conversion. Compared with the analogous gas-phase reaction,[1] HCOOH oxidation at a water-covered surface behaves substantially differently than those in gas phase or using a solvation model involving only a few water molecules. Using these models, we evaluated the detailed reaction process, including energies and geometric structures of intermediates and transition states under the influence of different solvation models and electrode potentials. Our calculations indicate that this potential-dependent electrochemical oxidation proceeds via a multi-path mechanism (involving both the adsorbed HCOOH and HCOO intermediates), a result succinctly rationalizing conflicting experimental observations. Moreover, this study highlights how subtle changes in electrochemical reaction environments can influence (electro-) catalysis.[2] The results provide a conceptual basis to better interpret the complicated reaction kinetics of HCOOH electro-oxidation.

[1] W. Gao, J. A. Keith, J. Anton, T. Jacob, Dalton Trans., 39, 8450 (2010).

[2] W. Gao, J. A. Keith, J. Anton, T. Jacob, J. Am. Chem. Soc., in press