Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 60: Chemistry at Solid/Liquid Interfaces
O 60.9: Vortrag
Mittwoch, 9. März 2016, 17:15–17:30, S052
Enhancement of electrocatalytical activity for oxygen evolution in bimetallic tetrapyridyl-porphyrine networks — Benjamin Wurster1, Doris Grumelli1, •Diana Hötger1, Rico Gutzler1, and Klaus Kern1,2 — 1Max Planck Institute for Solid State Research, D-70569 Stuttgart — 2Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne
Hydrogen and oxygen generated by electrochemical water splitting offers a source of clean and renewable energy. The limiting factor is the oxygen evolution reaction (OER) which is a demanding reaction as it involves a four-electron transfer (4 OH−→ O2 + 2 H2O + 4 e−, in alkaline electrolytes). As a result, the reaction has to overcome a large overpotential. Inspired by the reactivity of single metal atom catalysts and the structure of metallo-proteins, a bimetallic porphyrine catalyst for the OER was fabricated. Tetrapyridyl prophyrines provide two different coordination environments for the stabilization of single metal centers: the porphyrine ring and the pyridyl groups. Using this method we intentionally place Co and Fe atoms in either of the two coordination environment within a porphyrine monolayer on Au(111).
Compared to the single metal porphyrines the bimetallic networks show an increase in activity towards oxygen production of approximately two orders of magnitude. The enhancement of the activity is due to a cooperative effect between the metal centers positioned in the two coordination environments. Additionally, the reaction starts with an overpotential of about 300 mV, highlighting the favorable kinetics of the catalyst.