Electrodeposited MnO2/Au composite film with improved electrocatalytic activity for oxidation of glucose and hydrogen peroxide

The major drawback of currently used MnO2 film sensor is the loss of electrical conductivity due to the formation of a poorly conductive MnO2 layer. To overcome this problem, a coating in which the Au is alloyed with MnO2 has been developed. The fabrication of the codeposited film electrode of Au and MnO2 by using a cyclic voltammetric (CV) method was described, and systematic physical and electrochemical characterization was performed. This MnO2/Au film electrode enhanced MnO2 electrocatalytic activity. The oxidation process of glucose at the codeposited MnO2/Au shows a well-defined peak at 0.27 V in alkaline aqueous solution. In contrast, the glucose oxidation at Au modified glassy carbon electrode (GCE) just shows a shoulder wave at 0.42 V. The experimental results indicate that the modification of MnO2 on the surface of GCE significantly improved the electrocatalytic activity towards the oxidation of glucose. Further study shows that the MnO2/Au could also effectively catalyze the oxidation of hydrogen peroxide in pH 7.0 phosphate buffer solution (PBS).