Elektrochemické reakce železa a magnetitu na pevné a pastové elektrodě v alkalickém prostředí

Abstract

This bachelor thesis deals with application possibilities of modified carbon paste electrode in the study of electrochemical reactions of iron and magnetite in 1M NaOH medium. Experimental apparatus was constructed to perform electrochemical experiments at temperature 25°C. The polyamide holder with exchangeable tips was designed to observe reactions of the magnetite which served as a modifier of the carbon paste electrode. The possibilities of SEM microscopy and Raman spectroscopy were tested for analysis of the electroactive surface of the paste electrode. The cyclic voltammograms of solid and magnetite-modified electrodes were measured in 1M NaOH electrolyte and subsequently described by electrochemical equations. In addition, the influence of cycling on electrochemical equilibrium was tested on both electrodes, and the mechanism of the oxidation-reduction reaction was tested by means of scan speed. The comparison showed that the mechanism of oxidation-reduction reactions on solid and carbon paste electrode was similar, and in both cases was controlled by the diffusion of the reactant toward the electrode. Therefore, magnetite modified carbon paste electrode is a suitable tool for the study of magnetite reactions in alkaline electrolytes.