A novel Pb/PbO2 electrodes prepared by the method of thermal oxidation-electrochemical oxidation: Characteristic and electrocatalytic oxidation performance

The PbO2 electrodes were preservative and chemically stable but had the problem of the poor electrocatalytic oxidation activity and instability. In this research, Pb/PbO2 electrodes with good electrocatalytic oxidation activity and stability were prepared via a novel combined method of thermal oxidation and electrochemical oxidation, which was different form electrodeposition and coating method. Combined with the results analyzed by SEM, metallographic microscope, XRD, steady-state polarization and CV tests, the electrocatalytic oxidation performance was evaluated by the generation capacity of center dot OH and the removal efficiency of Congo red (CR). The experimental results put in evidence that the electrochemical oxidation time affected the electrochemical oxidation performance of Pb/PbO2 electrode by refinement of crystal sizes and strengthening of crystallinity which promoted oxygen evolution potential and center dot OH generation ability. The better center dot OH generation ability of 6-PbO2 encouraged the removal of CR (68.62%, 0.177 min(-1)) whose chromophore and ring structure of aromatic hydrocarbons was destroyed by center dot OH (7.82 x 10(-4) mu M min(-1)) with initial concentration of 20 mg.L-1 at 8 mA.cm-2 for 20 min. Moreover, 6-PbO2 owned stability for its compact surface. It showed that the stable 6-PbO2 electrode prepared by the thermal oxidation-electrochemical oxidation method had good electrocatalytic oxidation activity and excellent application potential, which were worthy of further research. (C) 2020 Elsevier B.V. All rights reserved.