在含[BMIM]PF6的电解液中电沉积制备PbO2电极的表征

Characterization of PbO_2 electrode prepared by electrodeposition in [BMIM]PF_6-containing electrolyte

将离子液体[BMIM]PF_6(1-丁基-3-甲基-咪唑六氟磷酸盐)添加到250 g/L Pb(NO_3)_2的电解液中,通过阳极电沉积在预制SnO_2+Sb_2O_3中间层的钛网上制备了PbO_2电极(标记为PbO_2 Ⅰ),通过扫描电镜(SEM)、X射线衍射(XRD)、加速寿命试验、极化曲线测量、电催化降解试验等对其进行了表征,并与采用F^-为添加剂时制备的PbO_2电极(标记为PbO_2 Ⅱ)进行对比。结果显示:PbO_2 Ⅰ电极的晶面取向为β(110),晶粒大小均匀,棱角较多,表面平整致密;PbO_2 Ⅰ电极的加速寿命和电极性能稳定期分别为168.8 h和101.2 h。与PbO_2 Ⅱ电极相比,PbO_2 Ⅰ电极在20 g/L Na_2SO_4电解液中的析氧电位高0.12 V,对100 g/L苯酚模拟废水的电氧化降解率和化学需氧量(COD)去除率分别高8个百分点和25个百分点,而能耗低23%。离子液体改变了PbO_2的结晶过程,提高了电极的稳定性和对苯酚的电催化活性,抑制了析氧副反应。

1-Butyl-3-methylimidazolium hexafluorophosphate{[BMIM]PF6},an ionic liquid,was added to a 250 g/L Pb(NO3)2 electrolyte,in which PbO2 electrode(coded as PbO2-I)was prepared by anodic electrodeposition on Ti mesh covered with an intermediate SnO2–Sb2O3 layer.The properties of the PbO2-I electrode were characterized and compared with the one prepared with F?as additive(coded as PbO2-II)by scanning electron microscopy(SEM),X-ray diffraction(XRD),accelerated life test,polarization curve measurement,and electrocatalytic degradation test.The results showed that the PbO2-I electrode is smooth and compact with an orientation ofβ(110),uniform crystal size,and many edges.The accelerated lifetime and stable performance period of the PbO2-I electrode are 168.8 h and 101.2 h,respectively.The PbO2-I electrode has an oxygen evolution potential 0.12 V higher than the PbO2-II electrode in a 20 g/L Na2SO4 electrolyte.The electrocatalytic degradation rate of phenol and the removal rate of COD(chemical demand of oxygen)by using the PbO2-I electrode are 8 and 25 percentage points higher and its energy consumption is 23%lower as compared to those by using the PbO2-II electrode.The ionic liquid changes the crystallization of PbO2,improves its stability and electrocatalytic activity,and inhibits the side reaction of oxygen evolution.