Lead dioxide is widely applied in anodic oxidation processes like the ozone generation and the degradation of various organic species in aqueous solution. In this paper, the correlation between the morphology of the lead dioxide particles and their ozone generating performance was investigated. The anode prepared by crude lead dioxide particles exhibited better performance in ozone generation than that prepared by milled lead dioxide particles. The reason lies in, probably, the higher stability of O-center dot on the surfaces of the crude lead dioxide particles. With 220-h running of the anode prepared with crude lead dioxide particles, the overall diameters of the lead dioxide particle decreased drastically, and many nano-scaled lead dioxide particles presented on the surfaces of the particles, which had resulted from recrystallization of the particles at high potentials. The two facts might be the main reason for the decline of the membrane electrode performance. Furthermore, a small percentage of alpha-lead dioxide detected in lead dioxide crystal may also decline the performance of the membrane electrode. (C) 2008 Elsevier B. V. All rights reserved.