高性能Bi3+掺杂改性PbO2电极的制备及表征

采用电沉积法制备了金属Bi3+改性PbO2(Bi-PbO2)电极,并通过扫描电镜(SEM)、X射线能谱(EDS)、X射线光电子能谱(XPS)、X射线衍射(XRD)、紫外-可见漫反射(UV-VisDRS)、荧光光谱(FP)、莫特-肖特基(Mott-Schottky)曲线、电化学阻抗谱(EIS)和线性极化扫描(LSV)等方法表征了其微结构和电化学性能.SEM、EDS和XPS结果表明,Bi3+以Bi2O3的形式掺杂进入PbO2镀层,同时其掺杂改性可明显改善PbO2镀层的微结构,使电极表面颗粒细化;XRD和UV-VisDRS分析结果显示Bi3+掺杂改性后,PbO2晶体的晶胞参数发生变化,同时禁带宽度(Eg)变小;荧光光谱分析表明Bi-PbO2电极可促进羟基自由基的产生,增强电极降解有机物的催化活性;电化学性能测试显示,Bi3+改性PbO2电极电催化活性的提升与电极的平带电势(Efb)负移、活性表面积增大、电化学反应电阻减小和析氧电位提高有关.

Preparation and Characterization of a Novel Bi-Doped PbO2 Electrode

A novel high-performance PbO2 electrode modified with Bi3+ (Bi-PbO2)was prepared by electrodeposition.The microstructure and electrochemical properties of the modified electrode were investigated using scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS), X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS),fluorospectrophotometry(FP),Mott-Schottky analysis,electrochemical impedance spectroscopy(EIS),and linear-sweep voltammetry(LSV).The results of SEM,EDS,XPS,XRD,and UV-Vis DRS show that insertion of Bi3+ ,which is in the form of Bi2O3 ,into the PbO2 film can reduce its particle size,change its crystal cell parameters,and narrow its bandgap(Eg ).FP analysis reveals that the electrocatalytic activity of the Bi-PbO2 electrode in the degradation of organic materials is higher than that of the PbO2 electrode because more hydroxyl radicals can be generated on its surface.Electrochemical performance tests show that the modified electrode has a more negative flat-band potential(E fb ),larger active surface area,lower charge-transfer resistance,and higher oxygen-evolution potential;these characteristics promote the electrocatalytic activity of the Bi-PbO2 electrode in the decomposition of organic materials.