低酸含Pb(Ⅱ)介质中石墨电极上PbO_2的电沉积

Lead dioxide electro-deposition on graphite electrode in low acidity medium containing Pb(Ⅱ)

研究了石墨、铂电极在含Pb(Ⅱ)的低酸溶液中,Pb(Ⅱ)经历电氧化过程中所发生的电化学反应行为。循环伏安测试结果表明:当采用石墨电极时,铅离子电氧化过程中,控制不同的电位区间对应于不同的电化学反应过程,当极化电位较低时,发生的是较低程度的石墨基体自身的电氧化过程;当极化电位至1.63 V时,将发生Pb(Ⅱ)电氧化生成二氧化铅的过程;当极化电位进一步升高至1.8V以上时,发生析氧等复杂的电氧化反应。XRD测试结果表明:较低酸性介质中采用恒电位沉积方法获得产物的主物相是β晶型PbO2,但也存在少量α晶型PbO2,为获得较纯的β晶型PbO2,须保证在较高酸度的含Pb(Ⅱ)介质中实施。

In this paper,the electro-oxidation behavior of Pb（Ⅱ） on graphite and platinum electrode in low-acid solution containing Pb（Ⅱ） is study.The results of cyclic voltammetry indicate that the control of different potential range corresponds to different electrochemical reaction process during lead ion oxidation process on graphite electrode.When the polarization potential is low,the low degree of graphite electro-oxidation process occurs.When the polarization potential is at 1.63 V,electro-oxidation process of Pb（Ⅱ） to PbO2 occurs;when the polarization potential is further increased to more than 1.8 V,the oxygen evolution reaction occurs.The results of XRD show that the main product obtained by potentiostatic deposition in low acidic medium is β-phase lead dioxide,but there is also a small amount of α-phase lead dioxide.In order to obtain relatively pure β-phase lead oxide,it should ensure a higher acidity medium containing Pb（Ⅱ）.