改性二氧化铅电极的制备及其在水处理中的应用

发布时间：2018-03-24 20:43

本文选题：改性Ti/PbO_2电极　切入点：中间层　出处：《东北师范大学》2017年硕士论文

【摘要】：电化学处理技术作为一种绿色环保且高效的物化处理技术,近年来受到很多科研工作者持续的研究与发展。传统的钛基二氧化铅电极虽具有较好的电催化性能,但二氧化铅极易与基体脱落,使电极在稳定性、催化性及使用寿命方面存在着缺陷。因此,需在原有优点的基础上对钛基二氧化铅电极进行改性,以进一步优化并提高该类电极的电化学性能,使其在电化学水处理技术中能更好的应用。本论文以中间层和表层两个方面来对钛基二氧化铅电极进行改性。通过热沉积法将配制成的中间层涂液均匀地涂于钛片上制备电极的中间层,再通过电沉积法电镀表层,从而得到改性钛基二氧化铅电极。本研究分别制备了Ti/RuO2-SnO2-CeO2/PbO2电极、Ti/RuO2-SnO2/PbO2-CeO2电极和Ti/RuO2-SnO2/PbO2-nano-TiO2电极。运用扫描电镜(SEM)、X射线衍射(XRD)及X射线光电子能谱(XPS)对电极形貌以及结构进行表征,结果显示三元中间层Ru、Sn、Ce元素的摩尔比以0.3:0.4:0.3为最佳;二元中间层以Ru、Sn元素的摩尔比以3:2为最佳,此时的中间层最为均匀致密且形成固溶体。表层修饰的CeO2或纳米TiO2以颗粒状分散于PbO2表面。实验中,利用循环伏安法(CV)对添加三元中间层制备的Ti/RuO2-SnO2-CeO2/PbO2电极进行了电化学测试,结果表明其析氧电位较未改性的Ti/PbO2电极提高了约1.0 V。以钛板为阴极,自制电极为阳极,以1 mol·L-1的H2SO4为电解液对所制备的电极进行寿命加速测试,结果显示,其寿命达到136小时,是Ti/PbO2电极的6.5倍,这表明中间层的添加提高了表层PbO2的附着能力,极大地增强了电极的稳定性。降解实验中,采用不锈钢网为阴极,自制电极为阳极,考察了4-氯酚(4-CP,100 mg·L-1)的电催化降解过程,电解120 min后,Ti/RuO2-SnO2-CeO2/PbO2电极性能良好,4-CP降解效率大于99%,而未改性的Ti/PbO2电极降解率为95%左右,但电极表面已破损脱落。添加二元中间层,表面掺杂修饰氧化铈制备的Ti/RuO2-SnO2/PbO2-CeO2电极,通过循环伏安法(CV)及电化学阻抗谱(EIS)对其进行电化学测试,结果显示表层氧化铈的修饰,Ce(NO3)3修饰镀液浓度以5 mmol·L-1为最佳,此时析氧电位为1.71 V左右,电极的电化学反应阻抗(Rct)最小,氧化膜电阻(Rf)最低,且寿命加速测试实验时间达到了215 h,分别是Ti/RuO2-SnO2/PbO2和Ti/PbO2电极的1.72倍和10.2倍。电催化降解100 mg·L-1的4-CP实验表明,在电流密度为30 mA·cm-2,电解80 min时,4-CP的去除率大于99%,140 min时,COD的去除率可达到95%以上。采用具有光催化性能的纳米TiO2掺杂修饰表层制备了Ti/RuO2-SnO2/PbO2-nano-TiO2电极,循环伏安法(CV)及电化学阻抗谱(EIS)测试结果表明,电极具有较高的析氧电位以及较小的电荷转移电阻,在紫外光照条件,利用该电极光电催化降解4-CP,降解80 min时,4-CP的去除率达到99%以上,电流效率达到10.81%。
[Abstract]:As a kind of green and efficient physicochemical treatment technology, electrochemical treatment technology has been continuously studied and developed by many researchers in recent years. Although the traditional titanium-based lead dioxide electrode has good electrocatalytic performance, However, lead dioxide is easy to fall off from the matrix, which makes the electrode have defects in stability, catalysis and service life. Therefore, it is necessary to modify the titanium based lead dioxide electrode on the basis of its original advantages. In order to further optimize and improve the electrochemical performance of this kind of electrode, In this paper, the titanium-based lead dioxide electrode was modified by interlayer and surface layer. The prepared interlayer solution was uniformly coated on titanium by thermal deposition. The intermediate layer of the electrode is prepared on the chip, And then electroplating the surface layer by electrodeposition, The Ti / Ruo _ 2-SnO _ 2 / PbO _ 2-CeO _ 2 and Ti/RuO2-SnO2/PbO2-nano-TiO2 electrodes were prepared respectively. The morphology and structure of the electrodes were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results show that the molar ratio of Ru-SnCe in the ternary interlayer is 0.3: 0.4: 0.3, and the molar ratio of Ru-Sn is the best in the binary interlayer at 3:2. The surface modified CeO2 or nano TiO2 was dispersed on the surface of PbO2 in a granular form. In the experiment, the electrochemical measurement of Ti/RuO2-SnO2-CeO2/PbO2 electrode prepared by adding ternary interlayer was carried out by cyclic voltammetry (CV). The results showed that the oxygen evolution potential of the prepared electrode was increased by about 1. 0 V compared with the unmodified Ti/PbO2 electrode. Using titanium plate as cathode, self-made electrode as anode and 1 mol L ~ (-1) H2SO4 as electrolyte, the life of the prepared electrode was accelerated. The results showed that the lifetime of the prepared electrode was 136h. This indicates that the addition of the intermediate layer improves the adhesion ability of the surface PbO2 and greatly enhances the stability of the electrode. In the degradation experiment, the stainless steel net is used as the cathode and the self-made electrode as the anode. The electrocatalytic degradation of 4-chlorophenol 4-CPN 100mg L ~ (-1) was investigated. After electrolysis for 120 min, the degradation efficiency of Ti / RuO _ 2-SnO _ 2-CeO _ 2 / PbO _ 2 / PbO _ 2 electrode was better than 994-CP, while the degradation rate of unmodified Ti/PbO2 electrode was about 95%, but the electrode surface was damaged and shedded. The surface doped cerium oxide (Ti/RuO2-SnO2/PbO2-CeO2) electrode was prepared by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that the best solution concentration of cerium oxide modified cerium oxide was 5 mmol L ~ (-1). When the oxygen evolution potential is about 1.71 V, the electrochemical reaction impedance (Rct) of the electrode is the smallest, and the resistance of the oxide film is the lowest. The experimental time of accelerated lifetime test reached 215 h, which was 1.72 times and 10.2 times of that of Ti/RuO2-SnO2/PbO2 and Ti/PbO2 electrodes, respectively. When the current density is 30 Ma / cm ~ (-2) and electrolysis time is 80 min, the removal rate of 4-CP can reach more than 95% when the electrolysis is more than 990.The Ti/RuO2-SnO2/PbO2-nano-TiO2 electrode is prepared by nano-doped TiO2 modified surface layer with photocatalytic property. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) showed that the electrode had higher oxygen evolution potential and lower charge transfer resistance. The photocatalytic degradation of 4-CPwith the electrode, the removal rate of 4-CP reached more than 99% and the current efficiency reached 10.81% after 80 min degradation.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O646.54;X703

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