A STUDY OF THE REDUCTION PROCESS OF ANODIC PBO2 FILM ON PB IN SULFURIC-ACID-SOLUTION

The reduction process of the anodic PbO2 film on lead formed at 1.4 V vs. Hg\Hg2SO4 in 4.5 M H2SO4 solution was investigated using chronoamp erometry, the photocurrent method and X-ray diffractometry. The experi mental results show that most of the beta-PbO2 and part of the alpha-P bO2 in the film can be converted to PbSO4 in about 1 s between 0.9 and 1.0 V vs. Hg\Hg2SO4. At a potential of 0.8 V vs. Hg\Hg2SO4 or less, a slower and more difficult conversion of alpha-PbO2 to alpha-PbOx (1<x <1.4) can be detected by the photoeffects of alpha-PbOx. The alpha-PbO x is gradually converted to t-PbO, which is completed in 75 min during the reduction at 0.6 V vs. Hg\Hg2SO4.