Electrocatalytic Properties of the Keggin-Type Co(II)-Substituted Heteropolyanion PWOCo(II)(HO)

The electrochemical properties of the Keggin-type Co(II)-substituted heteropolyanion PWOCo(II)(HO)(PWCo), as well as the electrocatalytic properties of PWCo towards the anodic oxidations of HO and CHOH were studied using the electrochemical methods such as cyclic voltammetry and AC impedance spectroscopy in this paper. An electrocatalytic mechanism of PWCo as an anodic medium was also proposed. It was found that PWCo 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 (i) of 5.7伊10 A窑cm. In particular, the couple exhibited a high electrocatalytic activity towards the anodic oxidation of HO in an acidic solution of pH 2.5, which can be coupled to catalyze the methanol oxidation.