| Popis: |
In acidic aqueous solutions, a glassy carbon electrode coated with an anodically-formed polymer of 1-aminophenazine (1-AP) mediates the reduction of dissolved 1-AP, Ce(IV), Fe(III) and O2. The effective surface area of the electrode appears to be reduced by several percent by the coating. Oxidation of V(II) is also mediated at the 1-AP-coated electrode but that of Fe(II) is blocked in accord with thermodynamic predictions. In neutral solution, reaction of the Fe(CN) 3− 2− 6 couple is not mediated at the coated electrode. The rate-determining step for mediated 1-AP, Fe(III) and Ce(IV) reduction at a coated rde is diffusion in the bulk solution, but reaction at or in the coating influences the rates of V(II) oxidation and O2 reduction. The reduction of O2 degrades the coating. |
