Kinetics And Mechanism Of Electrocatalytic Oxidation Of Ethanol On Platinum Electrode

The kinetics of electro-chemisorbed oxygenated species on the surface of platinum electrode was systematically studied by conventional electrochemical methods.The mediation of chemisorbed oxygenated species on the electrocatalytic oxidation of ethanol were studied.The effects of experimental conditions on the electrocatalytic oxidation of ethanol were studied and obtained the kinetic parameters of the corresponding electrochemical process.Combining high performance liquid chromatography?HPLC?with electrochemical methods,the primary mechanism of the electrocatalytic oxidation of ethanol was proposed.The electro-oscillations was investigated during the oxidation of platinum electrode,and the pH effect on the oscillations was discussed.The mechanism of nonlinear behavior in the process of electrooxidation of ethanol was speculated.?1?The anodic peaks corresponded to the electro-chemiorbed oxyganted species were analyzed by cyclic voltammetry scanning of platinum electrode in the blank solution.The potential of anodic peaks of ethanol oxidation is coincide with that of blank solutions.The mediation role of oxygenated species on the oxidation of ethanol was existed,which means that the oxidation of ethanol was process an indirect electron transfer path rather than the direct electron transfer of ethanol with platinum electrode.?2?Effects of experimental conditions on the electrocatalytic oxidation of ethanol were investigated.The current density was increased as increasing the additional ethanol concentrations.The anodic peak current density is increased with the increasing rate of the cyclic voltammetry scanning.The anodic peaks at 1.32 V in the positive scanning and at 0.7 V in the negative scanning were diffusion controlled process in the given sweep velocity range.Effect of H₂SO₄ on the electrooxidation of ethanol was studied in different concentrations of H₂SO₄ solution.The adsorbed?bi?sulfate competed with the adsorption OH^-on Pt electrode,inhibiting the electrooxidation of ethanol.The current density of anodic peak was increased with the increasing of temperature,and the value of apparent activation energy E_a corresponding to the surface reactions was calculated.?3?Non-linear behavior of ethanol electrooxidation on platinum electrode was discovered in the experiments,in which the pH effect was investigated,and the negative differential impedance exists in the system.The formation of platinum oxides as the positive feedback,and the dissolution of platinum oxides as a negative feedback was studied.In acidic and alkaline media,the positive feedback and the negative feedback as well as the pH effect on the nonlinear dynamics was analyzed.This dissertation has 45 graphs,4 tables,and 138 references.