Dresden 2017 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 20: Solid-Liquid Interfaces: Reactions and Electrochemistry - Experiment I

O 20.1: Vortrag

Montag, 20. März 2017, 16:30–16:45, WIL B321

Novel Quantitative Approach for Characterizing the Buried Metal/Coating Interfacial Kinetics Using Hydrogen Permeation Based Potentiometry — •Dandapani Vijayshankar and Michael Rohwerder — Max-Planck -Institut fur Eisenforschung GmbH

Electrochemical integrity of the buried metal/organic coating interface is crucially governed by the extent to which the cathodic oxygen reduction reaction (ORR) is curtailed. Current electrochemical techniques are unable to quantitatively probe such hidden interfaces due to the restricted ionic transport through the organic coating. Recently, a new non-destructive approach based on using hydrogen permeation as a tool to measure this ORR rate has been introduced. By correlating the dynamic equilibrium potential established between the the oxygen reduction and hydrogen oxidation reactions on the coated exit side with the hydrogen uptake rate on the entry side, a full current-potential curve I(U). Good concurrence between the I(U) curves derived from this permeation based potentiometry approach to that from standard three-electrode setup for the uncoated palladium, proved the correct measurement of the ORR rate. Underneath coatings, owing to interfacial charge transfer processes free of ion mobility, true ORR rate could be measured. Further, interfacial reaction kinetic mechanisms of the electrochemical ORR investigated by prolonged cathodic polarization experiments were found to destroy the interface similar to cathodic delamination process.