Pb-Zn的电沉积及其多孔电极的制备

Pb-Zn Electrodeposition and Preparation of the Porous Pb-Zn Electrode

铅基合金由于低熔点、高密度以及在酸性溶液中有较高析氢过电位等,被广泛应用于有机电合成中。由于Pb-Zn镀层的硬度较纯Pb高,本研究采用多孔Pb-Zn电极。在柠檬酸和EDTA-2Na为络合剂的甲磺酸镀液中电沉积出Pb-Zn镀层,循环伏安曲线和阴极极化曲线表明,Pb-Zn是分步沉积的,且均受扩散控制。采用X射线衍射、扫描电镜、能谱分析等研究了Pb-Zn镀层及其多孔电极组成和结构。结果表明,Pb-Zn镀层由Pb和Zn的混合物组成,Pb-Zn镀层用体积分数10%的H2SO4腐蚀后,Pb-Zn镀层表面晶粒细化,得到多孔Pb-Zn镀层。小幅度恒电位阶跃实验表明,多孔Pb-Zn电极具有更大的比表面积。

Due to the low melting point,high density,and higher over potential of hydrogen evolution reaction in acid solution,lead and its alloys were widely used in organic electrosynthesis.Porous Pb-Zn electrode was studied in this paper because the hardness of Pb-Zn coating was higher than that of pure Pb coating.The Pb-Zn coating was plated using a methylsulfonic acid bath,containing citrate and EDTA-2Na as a complexing agent.The cyclic voltammetry experiment and the cathode polarization showed that the Pb-Zn coating was deposited by step-by-step and was controlled by diffusion progress.The composition and structure of the Pb-Zn coating and its porous coating were studied by X-ray diffractometry（XRD）,scanning electron microscopy（SEM） and X-ray energy dispersive spectroscopy（EDS）,respectively.As a result,the Pb-Zn coating was formed by mixtures of Pb and Zn.After some Zn in the Pb-Zn coating was dissolved by 10vol% H2SO4,its surface grains become smaller,and the Pb-Zn coating was made into the porous Pb-Zn electrode.The less constant potential step experiment showed that the porous Pb-Zn electrode had a larger specific surface area.