超声对二氧化铅电极性质的影响
Effects of Ultrasonic Field on Characteristics of Lead Dioxide Electrodes

为提高PbO2电极在电催化氧化废水处理中的稳定性及催化性能,在超声场中用电沉积方法制备了PbO2电极,采用扫描电镜、X射线衍射、强化寿命测试、线性扫描测试及电催化降解等手段对所得电极的组成和性能进行了表征,并与未使用超声场的常规制备PbO2电极进行了性能比较。结果表明:超声场对PbO2电极的表面形貌有一定影响,产生了较多花束状的凸起,增加了电极的真实表面积;超声法PbO2电极的强化寿命和电压稳定期分别为166和165 h,明显长于常规法PbO2电极的100.5和50 h,表明超声法PbO2电极的稳定性优于常规法PbO2电极;超声法PbO2电极的析氧电位为1.67 V,高于常规法PbO2电极的1.60 V,表明超声法PbO2电极对于析氧副反应具有一定的抑制作用,有利于提高其电催化性能;在扫描电势达到2.0 V时,超声法PbO2电极的电流密度响应值为0.018 3 A？cm-2,远高于常规法PbO2电极的0.006 85 A？cm-2,表明它的导电性能更好,有助于降低电极在电解过程中的能耗;在对酸性红G溶液的降解过程中,超声法PbO2电极的表现优于常规法PbO2电极,其准一级反应动力学常数和总有机碳去除率分别为0.019 7 min－1和15.6％,均高于常规法PbO2电极的相应值,而其能耗值却低于常规法PbO2电极。由此证明,超声场的引入可改善PbO2电极的稳定性和催化性能。
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 0.006 85 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