Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 10: Metal/Water Interfaces: Structure and Reactivity
O 10.10: Vortrag
Montag, 16. März 2015, 17:15–17:30, HE 101
Two-dimensional bimetallic molecular networks as electrocatalyst for oxygen reduction and evolution — •Benjamin Wurster1, Doris Grumelli1,2, Diana Hötger1, Rico Gutzler1, and Klaus Kern1,3 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2Instituto Nacional de Investigaciones Fisicoquímicas, teóricas y aplicadas, La Plata, Argentina — 3Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne, Switzerland
Inspired by catalytically active bimetallic centers commonly found in biology we prepared bimetallic coordination networks and studied their electrocatalytic properties. Two different functional groups for metal coordiniation of 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) were used to selectively incoporate different metals in the structures. The samples were prepared under ultra-high vacuum (UHV) conditions by evaporating TPyP containing the first metal (Cu, Fe, or Co) in the pyrollic macrocycle. The second metal (Fe or Co) was sublimed in an additional step and is coordinated by the pyridyl groups. The metal-organic networks were characterized by scanning tunneling microscopy in UHV prior to studying their electrocatalytic activity towards oxygen reduction and evolution in alkaline media. Linear voltammetry experiments show that the electrocatalytic response in the oxygen reduction can be altered by choosing different combinations of metals. The incoporation of the second metal led to a higher oxygen evolution, while the stability of the electrochemical signal was influenced by the central metal within TPyP.