Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 8: Solid-liquid interfaces: Structure, Spectroscopy I
O 8.10: Vortrag
Montag, 12. März 2018, 12:45–13:00, MA 144
Surface plasmon resonance at electrified interfaces — •Ulmas E. Zhumaev and Katrin F. Domke — Max Planck Institute for Polymer Research, Mainz
Operating low-temperature fuel cells in the oscillatory regime is a promising approach to avoid the deactivation of platinum (Pt) catalyst by adsorbed carbon monoxide (CO). However, it remains an open question how to controllably activate the oscillatory regime. In the oscillatory regime, the Pt electrocatalyst undergoes spontaneous switching between the removal of adsorbed CO and the main reaction of the fuel cell. Such oscillations are accompanied by the formation of oscillatory CO concentration patterns on the Pt surface. Accessing these patterns with millisecond temporal and micrometer spatial resolutions using surface plasmon resonance (SPR) spectroscopy will help to gain insight into the oscillatory regime. To do so, the relationship between the SPR signal and the CO coverage under electrochemical (ec) conditions should be revealed. Our strategy is to define the contribution of different interfacial regions to the ecSPR signal by exploring well-known ec systems, e.g. Au(111) and Pt in H2SO4/Cl−/CO, with SPR spectroscopy. Our first results on Au(111) and Pt/Au(111) in 0.1 M H2SO4 suggest a predominant contribution of specific adsorption to the SPR signal, whereas non-specific adsorption and diffusion processes seem to have almost no contribution. The contribution of the surface charge seems to be rather complex and we present experimental approaches towards its understanding.