Electrocatalytic Properties of the Keggin-Type Co(II)-Substituted Heteropolyanion PW11O39Co(II)(H2O) 5-

The electrochemical properties of the Keggin-type Co(II)-substituted heteropolyanion PW11O39Co(II)(H2O) 5- (PW11Co), as well as the electrocatalytic properties of PW11Co towards the anodic oxidations of H2O2 and CH3OH were studied using the electrochemical methods such as cyclic voltammetry and AC impedance spectroscopy in this paper. An electrocatalytic mechanism of PW11Co as an anodic medium was also proposed. It was found that PW11Co showed a pair of pseudo-reversible redox peaks at the potentials of 1.367 V/1.266 V, corresponding to the redox responses of the Co(II)/Co(III) couple, apart from two pairs of reversible W要O skeleton redox peaks. A proton was involved in the electrode process of the Co(II)/Co(III) couple with an exchange current density (i0) of 5.7伊10 -6 A窑cm -2 . In particular, the couple exhibited a high electrocatalytic activity towards the anodic oxidation of H2O2 in an acidic solution of pH 2.5, which can be coupled to catalyze the methanol oxidation.