Effects of ultrasonic field on characteristics of lead dioxide electrodes

PbO₂ electrodes were fabricated in the ultrasonic field by the electro-deposition to enhance their stability and catalytic performance in the electro-catalytic oxidation wastewater treatment. The composition and the performance of the electrode were investigated by SEM, XRD, the acceleration test and the electro-catalytic degradation test. The performances of the ultrasonic-PbO₂ electrode were compared with that of the conventional PbO₂ electrode. The results show that the surface morphology of PbO₂ electrode is influenced by the ultrasonic field, and many flower-bunch-like bulges emerge on the surface of the electrode to increase its real surface area. The accelerated life and the voltage-stable period of the ultrasonic-PbO₂ electrode are 166 h and 165 h, respectively, which are obviously longer than 100.5 h and 50 h of the conventional PbO₂ electrode. The oxygen-evolution potential of the ultrasonic-PbO₂ electrode is 1.67 V, which is higher than 1.60 V of the conventional PbO₂ electrode. It indicates that the ultrasonic-PbO₂ electrode has a good performance in suppression of oxygen-evolution and gives an improvement on the electro-catalytic performance. When the scanning electric potential reaches 2.0 V, the corresponding current density of the ultrasonic-PbO₂ electrode is 0.018 3 A/cm², which is higher than 0.00685 A/cm² of the conventional PbO₂ electrode. This shows that the electro-conductivity of the former is better than that of the latter, which helps to reduce energy consumption in the electrolysis. The performance of the ultrasonic-PbO₂ electrode is also better than that of the conventional PbO₂ electrode in the degradation test of the acid red G solution. Its pseudo-first-order kinetics constant and total organic carbon removal rate are 0.019 7 min^-1 and 15.6%, respectively, which are both higher than those of the conventional PbO₂ electrode, while its energy consumption is lower than that of the conventional PbO₂ electrode in the degradation test. Therefore, it can be concluded that the stability and the catalytic performance of PbO₂ electrodes can be improved by introducing the ultrasonic filed.