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DY: Fachverband Dynamik und Statistische Physik

DY 5: Reaction-Diffusion Systems

DY 5.4: Talk

Monday, March 11, 2013, 15:45–16:00, H48

Experimental observation of solitons and backfiring during the electrochemical oxidation of carbon monoxide on Pt
— •Philipp R. Bauer¹, Antoine Bonnefont², and Katharina Krischer¹ — ¹Physik-Department, TU München, Germany — ²Institut de Chimie de Strasbourg, CNRS - Université de Strasbourg, France

Pattern formation during the electrooxidation of carbon monoxide is investigated with spatially resolved ATR-FTIR spectroscopy on thin platinum film electrodes. The use of a flow cell setup, in which the electrolyte passes the electrode from one side to the other, is effectively isolating the surface dynamics in one spatial dimension. The dynamic properties of the system are enriched by adding small amounts of halide ions to the solution.

Tracking the adsorbed CO on the surface reveals solitary reaction waves, which move perpendicular to the flow of the electrolyte across the electrode. The waves may backfire, leading to the creation of another wave, which moves in the opposite direction. Furthermore, interpenetrating wave collisions are found, in which two colliding pulses endure the collision and move on. This soliton-like behavior during collisions is explained with a three variable model capturing the interplay of the chemical autocatalysis of the CO-subsystem and two inhibitory variables, namely the potential drop across the electrolyte and the blocking effect of the halide ions.