关键词: 臭氧, 膜电极, 二氧化铅, 重结晶

Abstract: The solid polymer electrolyte composite membrane electrode was prepared by using Nafion membrane, lead dioxide and carbon-supported platinum as the electrolyte, anodic and cathodic catalyst, respectively. Morphology and structure studies of the membrane electrode with scanning electron microscopy and X-ray diffraction showed that with ozone production for 220 h, there was about 6% a-PbO2 in the lead dioxide anode. Meanwhile, the bonding structure of anode became loose and there were a lot of re-crystallized nano-sized particles on the surface of anode. The current efficiency of ozone evolution on the electrode decreased, and its voltage increased with time. It was found that the main reason for the degradations was change in morphology and structure of catalyst layer caused by recrystallization of lead dioxide, and the other reason was change in structure of lead dioxide induced by reduction of Pb2+ to Pb4+. With 180 h running of the electrode，the voltage and current efficiency of the electrode became steady, the reason might be the structure of anodic catalyst layer tending to remain stable.

Key words: ozone, membrane electrode, lead dioxide, re-crystallization