Effects of duty cycle on the preparation and property of PbO2-CeO2 nanocomposite electrodes

Abstract

PbO2-CeO2 nanocomposite electrodes were prepared by pulse electrodeposition in the lead nitrate solution containing CeO2 nanoparticles with different duty cycles. The effects of duty cycle on the morphology and phase structure were investigated by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. The SEM and XRD results show that the decrease of duty cycle can reduce the grain size of PbO2-CeO2 nanocomposite electrodes and make the electrodes more compact. The CeO2 content in composite electrodes increases with the decrease of duty cycle. The steady-state polarization curves and accelerated life tests demonstrate that the oxygen evolution overpotential and service life of PbO2-CeO2 nanocomposite electrodes increase with the decrease of duty cycle. The service life of PbO2-CeO2 nanocomposite electrodes prepared with 25 % duty cycle reaches 218 h which is 1.8 times longer than that of PbO2-CeO2 nanocomposite electrodes prepared by direct electrodeposition. The bulk electrolysis shows that the degradation of malachite green (MG) on the PbO2-CeO2 nanocomposite electrodes is the pseudo-first-order reaction and the MG and chemical oxygen demand (COD) removal efficiency on PbO2-CeO2 nanocomposite electrodes increases with the decrease of duty cycle, which can be attributed to the higher oxygen evolution overpotentials, electrochemical active surface area, and CeO2 content in the composite electrodes.