Abstract

Fe- and W-containing oxide heterostructures were formed on a titanium surface by plasma electrolytic oxidation in an alkaline tungstate–borate electrolyte containing complex Fe(III)-EDTA ions at anodic current densities of 0.1 and 0.2 A/cm². According to the data of X-ray diffraction analysis, the composition of all the formed samples is dominated by tungsten oxide WO₃ in a cubic modification. In addition, oxide layers obtained at a current density of 0.1 A/cm² contain Na_0.28WO₃, Fe₂O₃, and TiO₂ in modifications of rutile and anatase, while the coatings obtained at a current density of 0.2 A/cm² contain crystalline phases of wustite FeO and Fe₂ (WO₄)₃. The band gap determined by the Tauc method for a direct allowed transition is 2.64 eV for all samples. All formed coatings exhibit photocatalytic activity in the decomposition reaction of methyl orange (20 mg/L, pH 3.3) in the presence of hydrogen peroxide under UV irradiation. The coatings obtained at a current density of 0.1 A/cm² are active in degradation of methyl orange solution at pH 5.9 (close to the pH of wastewater).

中文翻译：

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WO3-FeO-Fe2O3和WO3-FeO-Fe2(WO4)3异质结构的等离子体电解合成及特性

摘要

在含有络合物 Fe(III)-EDTA 离子的碱性钨酸盐-硼酸盐电解质中，阳极电流密度为 0.1 和 0.2 A/cm ^{2 时，}通过等离子体电解氧化在钛表面上形成含 Fe 和 W 的氧化物异质结构。根据X射线衍射分析数据，所有形成的样品的组成以立方变体的氧化钨WO ₃为主。此外，在电流密度为 0.1 A/cm ^{2 时}获得的氧化层含有 Na _0.28 WO ₃、Fe ₂ O ₃和 TiO ₂的金红石和锐钛矿变体，而在电流密度为 0.2 A/cm 时获得的涂层²含有方氏体 FeO 和 Fe ₂ (WO ₄ ) _{3 的}结晶相。对于所有样品，由 Tauc 方法确定的直接允许跃迁的带隙为 2.64 eV。所有形成的涂层在紫外线照射下，在过氧化氢存在下，甲基橙（20 mg/L，pH 3.3）的分解反应中都表现出光催化活性。在0.1 A/cm ²的电流密度下获得的涂层在pH 5.9（接近废水的pH）时对甲基橙溶液的降解具有活性。