鉴定由添加钽控制的 Bi2O3 多晶型物的独特结构和光电特性,Journal of Materials Chemistry C

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鉴定由添加钽控制的 Bi2O3 多晶型物的独特结构和光电特性
Journal of Materials Chemistry C ( IF 5.7 ) Pub Date : 2022-11-25 , DOI: 10.1039/d2tc03718a
Taro Saito ₁ , Rafia Ahmad ₂ , Fuminao Kishimoto ₁ , Tomohiro Higashi ₃ , Masao Katayama ₄ , Luigi Cavallo ₂ , Kazuhiro Takanabe ₁

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通过添加不同量的钽 (Ta)，合成了氧化铋 (Bi) 的不同晶相。使用组合的实验和计算方法定量研究了它们的光电和氧化还原特性。确定并证明了根据 Ta 量以及合成温度将 α-Bi ₂ O ₃转化为 β-Bi ₂ O ₃和 δ-Bi ₂ O _{3的合成条件。}通过原位表征相变行为和晶体结构高温 X 射线衍射 (XRD)、热重-差热分析 (TG/DTA)、X 射线吸收近边结构 (XANES) 和扩展 X 射线吸收精细结构 (EXAFS)。采用具有自旋轨道耦合的 HSE 交换相关泛函的密度泛函理论计算被用于定量模拟 β-Bi ₂ O ₃和 δ-Bi ₂ O ₃的光电特性和能带结构。除了吸收系数和态密度外，还阐明了有效质量和介电常数。_{表征研究证实了添加 Ta 的 β-Bi 2} O ₃中 Ta-O 键的扭曲以及Bi和Ta原子在δ-Bi ₂ O ₃和Bi ₃ TaO ₇化合物中的取代位置。这些氧化物的还原性受程序升温还原 (TPR) 分析确认的晶相的强烈影响。这些发现可用作光电应用的氧化铋基准以及作为氧化还原活性中心或载体的热催化。

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Identification of distinctive structural and optoelectronic properties of Bi2O3 polymorphs controlled by tantalum addition

Diverse crystal phases of bismuth (Bi) oxides induced by the addition of different amounts of tantalum (Ta) were synthesized. Their optoelectronic and redox properties were quantitatively investigated using combined experimental and computational approaches. Synthesis conditions that transform α-Bi₂O₃ into β-Bi₂O₃ and δ-Bi₂O₃ in terms of the Ta quantity, as well as synthesis temperatures, are identified and demonstrated. The phase transition behavior and crystal structures were characterized by in situ high temperature X-ray diffraction (XRD), thermogravimetry–differential thermal analysis (TG/DTA), X-ray absorption near edge structures (XANES), and extended X-ray absorption fine structures (EXAFS). Density functional theory calculations employing the HSE exchange–correlation functional with spin–orbit coupling were used to quantitatively simulate the optoelectronic properties and band structures of β-Bi₂O₃ and δ-Bi₂O₃. Along with the absorption coefficient and density of states, effective masses and dielectric constants were elucidated. The characterization study confirmed the distortion of Ta–O bonds in the Ta-supplemented β-Bi₂O₃ and the substitutional positions of the Bi and Ta atoms in the δ-Bi₂O₃ and Bi₃TaO₇ compounds. The reducibility of these oxides was strongly influenced by the crystal phase confirmed by temperature-programmed reduction (TPR) analysis. These findings can be used as a bismuth oxides' benchmark for optoelectronic applications as well as thermal catalysis as the redox active center or the support.

更新日期：2022-11-28

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