Using electrochemical oscillations to probe the evolution of the electrode surface

Despite the constancy of all controllable parameters, many oscillatory systems shows a time-dependent behavior as the temporal oscillations evolve in time. In electrochemical systems, we have explained this uncontrollable drift in terms of surface reactions and the inactivation of the catalyst surface during the reaction.[1]In this work we explore the effect of very small surface defects,[2]deliberately created, on the oscillatory patterns, with the aim of proving the possibility of following the surface evolution along reaction. Figure1(a) the hydrogen ad/desorption regions for two surfaces that differ only slightly by the amount of defects. In (b), the same surfaces are tested towards the oscillatory electro-oxidation of methanol and the difference is clear: in one electrode only small amplitude oscillations (in red) are observed, whereas in the second surface an additional oscillatory pattern emerged, despite the nearly indistinguishable difference in the hydrogen region. Overall, we found that electrochemical oscillations can indeed be used as a very sensitive tool to characterize these surfaces when compared to conventional electrochemicalcharacterization. Further examples that corroborate this were observed.