Aurivillius phase Ca₂Bi₄Ti₅O₁₈ powders with micrometer size were produced by solid‐state reaction. X‐ray diffraction revealed that the powders had polar orthorhombic structure with space group of B2cb. Ca₂Bi₄Ti₅O₁₈ ceramic exhibited frequency independent dielectric anomaly at 774°C. The piezoelectric coefficient d₃₃ value of poled Ca₂Bi₄Ti₅O₁₈ pellets was 0.7 ± 0.2 pC/N. Both frequency independent dielectric anomaly and detectable d₃₃ value clearly indicated that Ca₂Bi₄Ti₅O₁₈ is a ferroelectric material with Curie point of 774 ℃. UV–vis absorption spectra revealed that Ca₂Bi₄Ti₅O₁₈ had a direct band gap of 3.2 eV. Photocatalytic activity of the Ca₂Bi₄Ti₅O₁₈ powders was examined by degradation of rhodamine B (RhB) under simulated solar light. 16% of RhB solution was degraded by Ca₂Bi₄Ti₅O₁₈ powders after 4 hours UV‐vis irradiation. With Ag nanoparticles deposited on the Ca₂Bi₄Ti₅O₁₈ powders surface, 50% of RhB was degraded under the same irradiation condition. The fitted degradation rate constant of Ag decorated Ca₂Bi₄Ti₅O₁₈ was 4 times higher than that of bare Ca₂Bi₄Ti₅O₁₈. This work suggested that the Aurivillius ferroelectric Ca₂Bi₄Ti₅O₁₈ is a promising candidate for photocatalytic applications.

中文翻译：

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Aurivillius相Ca2Bi4Ti5O18的铁电和光催化性能。

通过固相反应制备了微米级的Aurivillius相Ca ₂ Bi ₄ Ti ₅ O ₁₈粉末。X射线衍射表明该粉末具有极性正交结构，空间群为B 2 cb。Ca ₂ Bi ₄ Ti ₅ O ₁₈陶瓷在774°C下表现出与频率无关的介电异常。极化的Ca ₂ Bi ₄ Ti ₅ O ₁₈粒料的压电系数d ₃₃值为0.7±0.2 pC / N。既与频率无关的介电异常又可检测d ₃₃值清楚地表明，Ca ₂ Bi ₄ Ti ₅ O ₁₈是铁电材料，居里点为774℃。紫外可见吸收光谱表明，Ca ₂ Bi ₄ Ti ₅ O ₁₈的直接带隙为3.2 eV。通过在模拟太阳光下若丹明B（RhB）的降解来检查Ca ₂ Bi ₄ Ti ₅ O ₁₈粉末的光催化活性。Ca ₂ Bi ₄ Ti ₅ O ₁₈降解了16％的RhB溶液紫外可见光照射4小时后的粉末。通过将Ag纳米颗粒沉积在Ca ₂ Bi ₄ Ti ₅ O ₁₈粉末表面上，在相同的照射条件下，降解了50％的RhB。Ag修饰的Ca ₂ Bi ₄ Ti ₅ O ₁₈的拟合降解速率常数是裸Ca ₂ Bi ₄ Ti ₅ O ₁₈的拟合降解速率常数的4倍。这项工作表明Aurivillius铁电Ca ₂ Bi ₄ Ti ₅ O ₁₈是光催化应用的有希望的候选者。