Fabrication and Electrocatalytic Performance of a Two Dimensional SS-Pbo2 Macroporous Array for Methyl Orange Degradation

To further improve the electrocatalytic degradation activity of PbO 2 electrodes for refractory organic pollutant treatment, a novel two-dimensional β-PbO 2 macroporous array electrode (2D-PbO 2 ) was fabricated by electrochemical deposition based on a two-dimensional colloidal crystal template, which was constructed using the Langmuir-Blodgett film technique. The structure and surface morphology of 2D-PbO 2 electrodes and traditional flat electrodes (Flat-PbO 2 ) were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The anode polarization curves, cyclic voltammetry (CV) curves and electrochemical impedance spectroscopy (EIS) measurements were investigated to compare the electrocatalytic activity of the two kinds of electrodes. The electrocatalytic degradation of methyl orange (MO) was performed by CV, and UV spectroscopy was used to monitor changes during the electrocatalytic degradation process. The results show that the as-prepared electrode exhibited a two-dimensional ordered micron spherical cavity array structure with a large specific surface area. The coating surface is composed of single β-PbO 2 microcavities 5-6 μm in size, and the spacing of the micron holes is approximately 2 μm. Compared with the Flat-PbO 2 electrodes, the 2D-PbO 2 electrodes show a higher exchange current density ( j 0 =1.478×10 -5 A·cm -2 ), smaller apparent activation energy ( E a =12.09 kJ·mol -1 ), larger electric double layer capacitance ( C dl =60 μF·cm -2 ) and smaller charge transfer resistance ( R ct =16.89 Ω·cm 2 ), resulting in better electrocatalytic performance. In the electrocatalytic degradation process of MO, the conjugated chromophore group in the molecular structure of MO has been damaged by direct oxidation methods. The reaction followed pseudo first-order kinetics, and the value of the apparent rate constant ( k app ) is 0.06814 min -1 , approximately 2.35 times that of the Flat-PbO 2 electrodes (0.02902 min -1 ). The electrocatalytic degradation efficiency was significantly improved.