Experimental assessment of the sensitiveness of an electrochemical oscillator towards chemical perturbations

• Grant number: 12/21197-4
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: December 01, 2012
• End date: May 31, 2013
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Hamilton Brandão Varela de Albuquerque
• Grantee: Hamilton Brandão Varela de Albuquerque
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 09/07629-6 - Electrocatalysis IV: fundamental and applied aspects of electrocatalytic processes, bio-electrocatalysis and kinetic instabilities, AP.BIOEN.TEM

Abstract

In this study we address the problem of the response of a (electro)chemical oscillator towards chemical perturbations of different magnitudes. The chemical perturbation was achieved by addition of distinct amounts of trifluoromethanesulfonate (TFMSA), a rather stable and non-specifically adsorbing anion, and the system under investigation was the methanol electro-oxidation reaction under both stationary and oscillatory regimes. Increasing the anion concentration resulted in a decrease in the reaction rates of methanol oxidation and a general decrease in the parameter window where oscillations occurred. Furthermore, the addition of TFMSA was found to decrease the induction period and the total duration of oscillations. The mechanism underlying these observations was derived mathematically and revealed that inhibition in the methanol oxidation through blockage of active sites was found to further accelerate the intrinsic non-stationarity of the unperturbed system. Altogether, the presented results are among the few concerning the experimental assessment of the sensitiveness of an oscillator towards chemical perturbations. The universal nature of the complex chemical oscillator investigated here might be used for reference when studying the dynamics of other less accessible perturbed networks of (bio)chemical reactions. (AU)