Preparation Of PbO₂/Nanodiamond Composite Electrode And Its Electrocatalytic Properties

Nanodiamond (ND) electrode has attracted much attention in electroanalytical chemistry fields due to its unique electrochemical properties such as a wide potential window, a low background current, and a prolonged stability. However, some disadvantages of the ND electrodes such as poor electrical conductivity and low electrochemical activity make it practical significantly to prepared composite electrode.PbO₂/ND composite electrodes were obtained by potentiostatic deposition, and the reaction mechanism of phenol and aniline oxidation on the ND powder electrode and the PbO₂/ND composite electrodes were discussed. The effect of the electrodeposition potential and time on the electrochemical catalytic of the composite electrode to phenol and aniline oxidation were compared also.The results suggested that the catalytic activity of ND powder electrodes for the oxidation of phenol and aniline were remarkable. An irreversible oxidation reaction ocurred at the ND powder electrode in phenol. The decreasing of PH was helpful for the degradation of phenol. The anodic peak currents were direct proportion to the square of scan rates. Aniline was first oxidized on the ND powder electrode surface and then the oxidation of aniline gave rise to radical cations, which were polymerized to dimmer. The oxidation reaction of dimmer occurred at ND powder electrode and the anodic peak currents were also direct proportion to square of scan rates.PbO₂/ND composite electrodes were prepared at 1.8 V⁴ V for 10 s¹00 s, which were composed of the phase ofβ-PbO₂. The electrocatalytic activity to phenol and aniline of PbO₂/ND composite electrode increased with increasing electrodeposition potential, and then decreased when the electrodeposition potential was more than 2.5 V. It also increased with electrodeposition time, and increased slowly when the electroeposition time was more than 60 s.