The three-dimensional porous structure PbO 2 electrodes (3D-PbO 2 ) were successfully prepared in the lead nitrate solution by potentiostatically electrodeposition methods using oxygen bubbles as dynamic template. The morphology and structure of 3D-PbO 2 electrodes were investigated by scanning electronic microscopy (SEM) and X-ray diffraction (XRD). Compared with the traditional PbO 2 electrodes (Flat-PbO 2 ), 3D-PbO 2 electrodes possess the three-dimensional porous structure and finer grain size. The electrochemical properties of 3D-PbO 2 electrodes were investigated by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The 3D-PbO 2 electrodes show larger electrochemical active surface area, lower charge transfer resistance and higher oxygen evolution overpotential than Flat-PbO 2 electrodes. In the electrocatalytic degradation process of malachite green, the degradation rate constant of 3D-PbO 2 electrodes (0.05189 min −1 ) was 5.8 times than that of Flat-PbO 2 electrodes (0.00889 min −1 ).
PbO2-CeO2 nanocomposite electrodes were prepared by pulse reverse electrodeposition in the lead nitrate solution containing CeO2 nanoparticles. The effect of pulse reverse electrodeposition parameters, such as reverse pulse frequency, reverse peak current density and reverse duty cycle, on the content of CeO2 nanoparticles in the PbO2-CeO2 nanocomposite electrodes was investigated. The SEM and XRD tests show that PbO2-CeO2 nanocomposite electrodes possess finer grain size than PbO2-CeO2 nanocomposite electrodes (P) by pulse electrodeposition and PbO2-CeO2 nanocomposite electrodes (D) by direct current electrodeposition. The service life of PbO2-CeO2 nanocomposite electrodes can reach 285 h, which is 1.3 times longer than that of PbO2-CeO2 electrodes (P), and 2.3 times longer than that of PbO2-CeO2 electrodes (D). The electrochemical measurements show that PbO2-CeO2 nanocomposite electrodes possess highest oxygen evolution overpotential and largest electrochemical active surface area among these electrodes. The electrocatalytic property of PbO2-CeO2 nanocomposite electrodes was examined for the electrochemical degradation of methylene blue (MB). The bulk electrolysis shows that PbO2-CeO2 nanocomposite electrodes exhibit the highest COD removal efficiency and lowest energy consumption, which can be ascribed to the highest oxygen evolution overpotential, largest electrochemical active surface area and highest CeO2 content.
PbO 2 -TiO 2 nanocomposite electrodes were prepared by the electrodeposition method in the lead nitrate solution containing TiO 2 nanoparticles. The influences of TiO 2 concentration, current density and stirring rate on the weight percentage (wt%) of TiO 2 nanoparticles in the PbO 2 -TiO 2 nanocomposite electrodes were investigated. TiO 2 content in the PbO 2 -TiO 2 nanocomposite electrodes reaches 8.79 wt% from lead nitrate solution containing 8 g L −1 TiO 2 nanoparticles with current density at 30 mA cm −2 and stirring rate at 120 rpm. The morphology and structure of PbO 2 -TiO 2 nanocomposite electrodes were characterized by scanning electrons microscopy (SEM) and X-ray diffraction (XRD). PbO 2 -TiO 2 nanocomposite electrodes are finer and more compact than PbO 2 electrodes. The service life of PbO 2 -TiO 2 nanocomposite electrodes reaches 149 h, which is four times longer than that of PbO 2 electrodes. The photoelectrochemical property of PbO 2 -TiO 2 nanocomposite electrodes was investigated by linear sweep voltammogram (LSV), photocurrent response (PCR) and electrochemical impedance spectroscopy (EIS) under UV irradiation. The results show that PbO 2 -TiO 2 nanocomposite electrodes possess remarkable photocurrent response under UV irradiation. The MB and COD removal efficiency reaches 98.5% and 70.7% by photoelectrocatalytic degradation after 120 min, the degradation process follow the first-order reaction kinetics. The results demonstrate that PbO 2 -TiO 2 nanocomposite electrodes are promising photoelectrocatalytic anode materials.In recent years, TiO 2 particles have been successfully used as photocatalyst to treat organic pollutants. 1-4 However, there are two obvious shortcomings in actual application: first is that TiO 2 particles are difficult to separate from aqueous solution when the photocatalytic reaction is carried out in the TiO 2 suspension system; second is the low quantum yield due to the rapid recombination of photo generated holes and electrons. 5,6 To solve these problems, TiO 2 particles can be immobilized on the electrode and the electrochemically assisted photocatalysis could be realized by means of the external electric field, which solves the problem of TiO 2 recovery and low quantum efficiency. PbO 2 electrodes possess high electrical conductivity, good stability and are easily obtained at a low cost. 7-9 In addition, the electrodes possess relatively high electrocatalytic ability in the degradation process of organic pollutants. 10-14 PbO 2 electrodes can immobilize TiO 2 particles to obtain PbO 2 -TiO 2 composite electrodes by anodic electrodeposition in the lead nitrate plating bath containing TiO 2 particles. Recently, A.B. Velichenko et al 15-17 has prepared PbO 2 -TiO 2 composite electrodes, the results show that the life-time of PbO 2 -TiO 2 composite electrodes is twice as long as that of PbO 2 electrodes. 18 Li et al 19 studied the electrochemically assisted photocatalytic degradation of acid orange 7 using β-PbO 2 electrodes modified by TiO 2 , the TiO 2 modified β-PbO 2 ...
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