Electrodes in the “dry”

Electrochemical interfaces are everywhere: even on the “dry” surfaces of metals exposed to the atmosphere or covered by organic coatings. In these cases nanoscopic water layers are present on the surface of the metals. By use of the Kelvin probe technique it can be shown that the work function measured on these systems can be directly interpreted as electrode potentials (see e.g. [1]). Unlike to standard electrochemistry, however, the electrochemical interface extends over the whole available electrolyte volume. The consequences this has on the kinetics of electrochemical reactions is a fundamental research topic within the group. Part of this research is correlated with the fundamental questions addressing the electrochemical basis of the novel Kelvin probe technique for the detection of hydrogen (see e.g. [2]). Another important part of research is being carried out within the framework of the Excellence Cluster RESOLV (see http://www.ruhr-uni-bochum.de/solvation/).

This research is also correlated to electrochemistry at buried interfaces. This topic is the key issue behind corrosion driven coating delamination, where electrochemical reactions occur in the nanoscopically confined interfacial reagion between organic coating and metal. One example is our research carried out with sum frequency generation (SFG) at self-assembled monolayer under electrochemical control (see [3])

Hausbrand, R.; Stratmann, M.; Rohwerder, M.: The physical meaning of electrode potentials at metal surfaces and polymer/metal interfaces: Consequences for delamination. Journal of the Electrochemical Society 155 (7), pp. C369 - C379 (2008)
Evers, S.; Rohwerder, M.: The hydrogen electrode in the “dry”: A Kelvin probe approach to measuring hydrogen in metals. Electrochemistry Communications 24, pp. 85 - 88 (2012)
Koelsch, P.; Muglali, M. I.; Rohwerder, M.; Erbe, A.: Third-order effects in resonant sum-frequency-generation signals at electrified metal/liquid interfaces. Journal of the Optical Society of America B-Optical Physics 30 (1), pp. 219 - 223 (2013)
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