作　　者： ; ; ; ; ;

机构地区： 华南农业大学理学院应用化学系

出　　处： 《分析化学》 2010年第5期653-658,共6页

摘　　要： 采用镀膜/循环伏安法制备了PbO2修饰玻碳电极。在Pb(NO3)2溶液中,在-0.7V将Pb膜沉积在玻碳电极表面,然后在5mol/L NaOH溶液中以100mV/s速度在-1.0～1.0V循环伏安扫描20次,PbO2膜均匀沉积在玻碳电极表面。采用交流阻抗法监控电极修饰每一过程,环境扫描电镜表征电极表面形貌。探讨了PbO2膜的沉积机理及其电化学行为,表面活性位点覆盖量为7.5×10-10mol/cm2。PbO2修饰电极对H2O2电氧化表现出较高催化活性,起始氧化电位低至0.1V,考察了影响催化活性的因素。计时电流法测定H2O2(工作电位0.40V),响应时间小于2s;线性范围为5.0×10-6～5.5×10-4mol/L;检出限1.1×10-6mol/L(信噪比为3)。在实际水样中H2O2测定结果满意。电极在室温环境下储存30d,其催化活性基本不变。该修饰电极制备工艺简单、重现性良好、稳定性高。 A PbO2 film modified glassy carbon electrode （PbO2/GC） was prepared by a novel method of film plating/cyclic voltammetry. First, the Pb film was cathodically deposited on GC surface at -0.7 V in 0.5 mol/L NaClO4 solution containing 0.36 mmol/L Pb2＋. Then, the well defined PbO2 film was in situ deposited on GC surface by cyclic voltammetry at -1.0-1.0 V, 100 mV/s in 5 mol/L NaOH solution. The successful stepwise plating procedure and surface morphology of modified electrode were characterized by electrochemical impedance spectroscopy and scanning electron microscopy, respectively, which verified the effective electrodeposition of PbO2 film. The mechanism of PbO2 film formation and its electrochemical behavior were investigated by cyclic voltammetry. The surface concentration of PbO2 active sites was 7.5×10-10 mol/cm2. The PbO2/GC showed high catalytic activity for the electrooxidation of H2O2, whose initial oxidative potential was only 0.1 V. The main factors influencing the catalytic activity of PbO2/GC were explored. The chronoamperometric detection of H2O2 was carried out at 0.40 V in 0.1 mol/L NaOH solution. The response time was 2 s and the linear range was 5.0×10-6-5.5×10-4 mol/L with a detection limit of 1.1×10-6 mol/L（S/N=3）. The results of H2O2 determination in real water sample were satisfied. No measurable reduction in catalytic activity of PbO2/GC was found by storing the electrode in ambient conditions for 30 days.

关 键 词： 二氧化铅 玻碳电极 镀膜 循环伏安法 电催化

领　　域： [理学] [理学]