Many systems from all fields of science possess a common and most fascinating property: They may form patterns in space and/or time from originally uniform states when kept far from thermodynamic equilibrium. The basic principles governing the formation of spatio-temporal structures and their dynamics are universal, i.e. they are independent of the nature of the specific system.
We study the spontaneous formation of adsorbate and/or reactivity patterns at electrode surfaces, both experimentally and theoretically with the aim
- to contribute to an understanding of the fundamental mechanisms, governing pattern formation in non-equilibrium systems,
- to unravel the origin of instabilities in electrochemical systems,
- to shed light on dynamic instabilities in systems of practical relevance and
- to exploit them in technological applications (such as metal or semiconductor corrosion, in fuel cells or in electrocatalysis).
Experimental techniques include
- scanning tunneling microscopy (STM) and atomic force microscopy,
- ellipsometric microscopy for surface imaging (EMSI),
- spatially resolved FTIR spectroscopy (SEIRAS) and
- potential micro-probes.
Theoretically, we develop models describing the spatio-temporal behavior, investigate their solutions using state of the art bifurcation analysis and relate the models to prototype equations in nonlinear dynamics, such as reaction-diffusion equations of the activator-inhibitor type, or the complex Ginzburg-Landau equation.