title: 1/f2noise in bistable electrocatalytic reactions on mesoscale electrodes.
abstract: The formation of a self-organized spatial domain during current-controlled CO oxidation, a kinetically bistable reaction, is investigated experimentally and by deterministic simulations as a function of the electrode size and of the supporting electrolyte concentration. Decreasing the microelectrode size leads to the suppression of the spatial instability at the electrode and thus stabilizes the S-NDR branch of the reaction. The critical microelectrode size capable of supporting sustained domain formation is shown to be strongly affected by the sulfuric acid concentration, the characteristic time of the positive feedback loop increasing with the sulfate concentration. Furthermore, we demonstrate that for microelectrode diameters close to the instability threshold, small amplitude electrochemical potential fluctuations appear in the system. These potential fluctuations cannot be captured by deterministic mathematical models and are attributed to a strong enhancement of molecular fluctuations or intrinsic noise in the vicinity of the spatial instability. Analysis of the electrochemical noise revealed a 1/f2frequency dependence and several common features with neuronal shot noise.
authors.affiliation: Institut de Chimie et Procédés pour l'Energie, l'Environnement et la Santé, UMR 7515 of CNRS-Université de Strasbourg-ECPM, 25 rue Becquerel, 67087 Strasbourg, France.
authors.forename: S
authors.initials: S
authors.lastname: Bozdech
authors.forename: K
authors.initials: K
authors.lastname: Krischer
authors.forename: D A
authors.initials: DA
authors.lastname: Crespo-Yapur
authors.forename: E
authors.initials: E
authors.lastname: Savinova
authors.forename: A
authors.initials: A
authors.lastname: Bonnefont