阳极Pb(II)氧化物膜的阴极还原

采用X射线衍射、光电流谱、线性电位扫描和开路电位衰退等方法研究了Pb电 极在0.9 V(vs.Hg/Hg_2SO_4), 4.5 MOL/l h_2so_4溶液中生长2 h所得的阳极Pb (II)氧化物膜的阴极还原行为。实验结果表明；阳极Pb(II)氧化物膜主要由PbO微 粒和PbO·PbSO_4微粒组成，微粒间液膜可供离子输运；在LSV负向扫描过程中，阳 极Pb(II)氧化物膜是按溶解－沉积机理还原的，首先PbO微粒借助该微粒间的液膜 还原为金属铅，而待PbO微粒表面层转化的金属铅与PbO·PbSO_4微粒接触后，则 PbO·PbSO_4就和PbO一起还原，而以PbO·PbSO_4的还原进程略快。

The Cathodic Reduction Process of the Anodic Pb(II) Oxides Film Formed on Lead

The cathodic reduction behavior of the anodic Pb(II) oxides film formed on Pb for 2 h in 4.5 mol/L H_2SO_4 solution at 0.9 V (vs. Hg/Hg_2SO_4) has been investigated by X-ray diffraction method (XRD), photocurrent measurements, linear sweep voltammetry (LSV) and open circuit decay curve (OCD). The results show that: (1) The major components of the anodic Pb(II) oxides film are PbO particles and PbO· PbSO_4 particles, and the interstitial liquid may serve as the major passage for ion transportation during the reduction of the anodic film. (2) The anodic Pb(II) oxides film is reduced via a dissolution- precipitation mechanism during the negative LSV. At first, the surface layer of the PbO particles is reduced to the metal Pb, and then the PbO and PbO·PbSO_4 particles are reduced together, when the metal Pb in the surface layer of the PbO particles meets the PbO·PbSO_4 particles, and the reduction of PbO·PbSO_4 particles is slightly faster than that of the PbO particles.