Preparation of Lead Dioxide Modified Glassy Carbon Electrode by a Novel Film Plating/Cyclic Voltammetric Method and Its Electrocatalytic Properties
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.