Instabilidaes temporais na reacao de eletrooxidacao de metanol sobre platina.

• Grant number: 05/02409-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2005
• End date: September 30, 2007
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Hamilton Brandão Varela de Albuquerque
• Grantee: André Luis Martins
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

From the energetic point of view, methanol electrooxidation can be considered one of the most important electrocatalytic reactions and has been extensively investigated. On the other hand, there are only very few contributions dedicated to the understanding of the processes underlying the temporal self-organization present in this reaction when carried out under certain conditions. The main goal of the present project is to investigate systematically the non-linear processes present in the methanol electrooxidation reaction on policrystalline platinum electrodes. Special attention will be devoted to the identification of the conditions under which oscillations are observed, as well as to the study of the impact of the experimental conditions on the temporal patterns. Based on the different steps involved in the general mechanism accepted for the methanol electrooxidation reaction on platinum in acid media, the experimental strategy includes the study of the impact of the following parameters on the oscillatory dynamics: concentration of methanol, concentration and composition of the electrolyte, temperature, and the values of the series resistance connected between the working electrode and the potentiostat. The interface will be studied either under potentiostatic or galvanostatic operation mode and mass changes at the electrode surface will be investigated by means of an electrochemical quart crystal nanobalance. (AU)