离子液体对PbO2电极性能的影响

目的 提升PbO2电极寿命以及对酚类废水的电氧化催化活性和选择性。方法 分别添加离子液体1-丁基-3-甲基-咪唑六氟磷酸盐（[BMIM]PF6）和1-乙基-3-甲基-咪唑四氟硼酸盐（[Emim]BF4）至Pb(NO3)2溶液中，用阳极电积法制备了有SnO2+Sb2O3中间层的PbO2电极。通过扫描电镜（SEM）、X射线衍射仪（XRD）、加速寿命实验、线性扫描和循环伏安测试、电氧化降解实验等考察了不同离子液体的电离产物对电极性能的影响，并与采用F-修饰的常规PbO2电极的性能进行了对比。结果 离子液体修饰的PbO2电极晶粒结晶度高，晶面取向发生改变，晶粒大小均一度高，表面平整致密、棱角多，电极有效表面积和活性点增多，且[BMIM]PF6修饰的PbO2优于[Emim]BF4修饰的PbO2。[BMIM]PF6修饰的PbO2和F-修饰的PbO2的加速寿命和电极性能稳定期分别为168.8、162.6 h和101.2、69.8 h，析氧电位分别为1.71 V和1.59 V。循环伏安显示，[BMIM]PF6修饰PbO2氧化峰电位更小，氧化峰电流更大，相同条件下，[BMIM]PF6和F-修饰PbO2对p-NP废水的电氧化降解率和有机碳去除率分别为95.7%、87.1%和85.2%、61.5%，而电解槽槽压分别为3.26 V和3.47 V。结论 离子液体[BMIM]PF6、[Emim]BF4修饰PbO2电极的结晶度、晶粒均一性、致密性增强，电极活性点增多，且由于两种离子液体电离的离子大小不同，导致对电沉积晶粒的空间位阻不同，使得前者强于后者。晶粒形态和组织结构的差异，使得[BMIM]PF6修饰PbO2对酚类废水的电氧化催化活性、选择性和寿命显著增强。

Influence of the Ionic Liquid on the Performance of Lead Dioxide Electrode

The work aims to improve the service life of lead dioxide electrode, and its electrocatalytic activity and selectivity for the phenolic wastewater. [BMIM]PF6 and [Emim]BF4 ionic liquid was added into Pb(NO3)2 solution and PbO2 electrode with SnO2 and Sb2O3 interlayer was prepared via electro-deposition. The influence of ionization product of different ionic liquids on the electrode performance was investigated by scanning electron miscroscopy (SEM), X-ray diffraction (XRD), accelerated life test, anodic linear polarization curves, cyclic voltammetry and electro-oxidative degradation experiment. The performance of F- modified PbO2 electrode was used for comparison. The PbO2 electrode modified by ionic liquid had high crystal grain crystallinity, changed crystal plane orientation, uniform crystalline size, smooth and compact surface with many edges and corners, and increased effective surface area and active points. [BMIM]PF6 modified PbO2 electrode was better than [Emim]BF4 modified PbO2 electrode. The accelerated life and stability period of [BMIM]PF6 modified PbO2 and F- modified PbO2 were 168.8 and 162.6 h and 101.2 and 69.8 h, respectively. The oxygen evolution potential was 1.71 V and 1.59 V, respectively. Cyclic voltammograms showed the potential of oxidation peak of [BMIM]PF6 modified PbO2 was smaller and its current of oxidation peak was larger than F- modified PbO2. Under identical conditions, the removal ratio of p-nitrophenol using [BMIM]PF6 modified PbO2 electrode and F- modified PbO2 was 95.7% and 87.1%, respectively and the removal percentage of organic carbon was 85.2% and 61.5%, and the cell voltage was 3.26 and 3.47 V, respectively. The crystallinity, homogeneity and compactness of PbO2 electrode modified by ionic liquid [BMIM]PF6 and [Emim]BF4 are enhanced, and the active points of electrode are increased, and due to the different ionized ion sizes of the two ionic liquids, the spatial resistance of the electrodeposited grains is different, which make the former better than the latter, and the difference of crystal morphology and microstructure makes the catalytic activity of PbO2 modified by [BMIM]PF6 for phenolic wastewater electrooxidation, selectivity and longevity significantly increase.