Understanding reaction mechanisms using dynamic electrochemical impedance spectroscopy: Methanol oxidation on Pt

Abstract

Data from a combined cyclic voltammetry and dynamic electrochemical impedance spectroscopy (dEIS) study of the methanol oxidation reaction (MOR) at high temperatures was revisited using a new method for mechanistic modeling. Through iterative optimization of kinetic parameters, a total of five reaction mechanisms of the indirect pathway of the MOR were modeled. The calculated dEIS spectra from the kinetic parameters were used to verify the reaction mechanisms and best fits were found where i) water adsorption is reversible and hinders the MOR at lower potentials (< 0.50 V vs RHE), and ii) the surface reaction between adsorbed CO and OH is chemical.