The Eectrochemical Behaviors Of Transition Metal-containing Polyoxometalates, Metallporphyrins And Their Electrocatalysis For Oxygen Reduction

The electrochemical behaviors of the transition metal-containing polymetalates,metal porphyrins and Schiff base metal complexes, as well as their electrocatalyticactivities for oxygen reduction were studied by cyclic voltammetry.Except for the copper-containing polymetalates, all the other transitionmetal-containing polymetalates studied in this research showed similar cyclicvoltammetric behavior, while their electrocatalytic activities for oxygen reduction werequite different. Within them the CuW_n and FeW₇ showed the highest catalytic activities.These results suggested that the transition metal ions incorporated into thepolymetalates structure worked as the electrocatalytic centers of the polymetalates.The polymetalates modified electrode showed good electrocatalytic activity forthe reduction of H₂O₂ to H₂O, and the Co(â…¡) porphyrin modified electrode showedgood electrocatalytic activity for the reduction of O₂ to H₂O₂. To achieve the reductionof O₂ to H₂O, the electrode was modified with both polymetalates and Co(â…¡)porphyrins. Such modified electrode showed much higher electrocatalytic activity forthe oxygen reduction, compared with that modified with only polymetalates or Co(â…¡)porphyrins.The results from this thesis can provide information for exploration of the oxygenreduction on the cathode.