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采用电沉积法制备了离子液体[Emim]BF_4改性PbO_2电极。通过电化学氧化降解苯酚实验对电极催化性能进行了考察,发现苯酚模拟废水的COD去除率符合一级反应动力学,[Emim]BF_4改性PbO_2电极的速率常数为0.007 39 min~(-1),明显高于未改性PbO_2电极的速率常数0.003 83 min~(-1)。采用SEM、XRD、XPS对电极表面结构进行表征。结果显示,[Emim]BF_4改性钛基PbO_2涂层表面致密规整、结晶度高、晶格氧含量高。通过莫特-肖特基曲线、稳态极化和线性扫描伏安法考察了电极的电化学性质。结果表明,改性电极表面氧空位含量相比未改性电极大大降低,改性电极的析氧过电位相比未改性电极有明显提高。通过与未改性电极结构和电化学性质的对比研究,得出改性电极催化活性的提高主要是由于其氧空位含量较低,从而降低了氧化物电极表面羟基自由基(·OH)向晶格氧(O_(lat))转移的发生率。
The ionic liquid [Emim] BF 4 modified PbO 2 electrode was prepared by electrodeposition. The catalytic performance of the electrode was investigated by means of electrochemical oxidation and phenol degradation. It was found that the COD removal efficiency of phenol simulated wastewater conformed to the first order reaction kinetics. The rate constant of [Emim] BF 4 modified PbO 2 electrode was 0.007 39 min -1 , Which was significantly higher than that of unmodified PbO_2 electrode (0.003 83 min -1). The surface structure of the electrode was characterized by SEM, XRD and XPS. The results show that the surface of [Emim] BF_4 modified titanium-based PbO_2 coating is dense and regular, with high crystallinity and high lattice oxygen content. The electrochemical properties of the electrode were investigated by Mott-Schottky curve, steady-state polarization and linear sweep voltammetry. The results showed that the oxygen vacancy content on the surface of the modified electrode was greatly reduced compared with that of the unmodified electrode, and the oxygen evolution overpotential of the modified electrode was significantly higher than that of the unmodified electrode. Through the comparison with the structure and electrochemical properties of the unmodified electrode, it is concluded that the improvement of the catalytic activity of the modified electrode is mainly due to its low oxygen vacancies, which reduces the hydroxyl radical (· OH) on the surface of the oxide electrode Oxygen (O_ (lat)) the incidence of metastasis.