Laboratory of Thin Film Technologies, Far Eastern Federal University, Ajax Bay 10, Russky Island, Vladivostok 690922, Russia.
Laboratory 'Photoactive Nanocomposite Materials', St. Petersburg State University, Ulyanovskaya 1, St. Petersburg 198504, Russia.
Photochem Photobiol Sci. 2021 Sep;20(9):1147-1160. doi: 10.1007/s43630-021-00086-y. Epub 2021 Aug 17.
This article revisits the properties of BaBiO examined extensively in the last two decades because of its electronic properties as a superconductor and as a semiconductor photocatalyst. Solid-state syntheses of this bismuthate have often involved BaCO as the barium source, which may lead to the formation of BaBiO/BaCO heterostructures that could have an impact on the electronic properties and, more importantly, on the photocatalytic activity of this bismuthate. Accordingly, we synthesized BaBiO by a solid-state route to avoid the use of a carbonate; it was characterized by XRD, SEM, and EDX, while elemental mapping characterized the composition and the morphology of the crystalline BaBiO and its thin films with respect to structure, optoelectronic, and photocatalytic properties. XPS, periodic DFT calculations, and electrochemical impedance spectroscopy ascertained the electronic and electrical properties, while Raman and DRS spectroscopies assessed the relevant optical properties. The photocatalytic activity was determined via the degradation of phenol in aqueous media. Although some results accorded with earlier studies, the newer electronic structural data on this bismuthate, together with the photocatalytic experiments carried out in the presence of selective radical trapping agents, led to elucidating some of the mechanistic details of the photocatalytic processes that previous views of the BaBiO band structure failed to address or clarify. Analytical refinement of the XRD data inferred the as-synthesized BaBiO adopted the C symmetry rather than the I structure reported earlier, while Tauc plots from DRS spectra yielded a bandgap of 2.05 eV versus the range of 1.1-2.25 eV reported by others; the corresponding flatband potentials were 1.61 eV (E) and - 0.44 eV (E). The photocatalytic activity of BaBiO was somewhat greater than that of the well-known Evonik P25 TiO photocatalyst under comparable experimental conditions.
本文重新考察了 BaBiO 的性质，因为它具有超导性和半导体光催化剂的电子性质，在过去二十年中对其进行了广泛研究。这种铋酸盐的固态合成通常涉及 BaCO 作为钡源，这可能导致 BaBiO/BaCO 异质结构的形成，这可能对电子性质产生影响，更重要的是，对这种铋酸盐的光催化活性产生影响。因此，我们通过固态途径合成了 BaBiO，以避免使用碳酸盐；通过 XRD、SEM 和 EDX 对其进行了表征，而元素映射则对 BaBiO 的晶体及其薄膜的组成和形貌进行了表征，以了解其结构、光电和光催化性能。XPS、周期性 DFT 计算和电化学阻抗谱确定了电子和电气性能，而 Raman 和 DRS 光谱评估了相关的光学性质。通过在水介质中降解苯酚来确定光催化活性。尽管有些结果与早期的研究结果一致，但关于这种铋酸盐的新的电子结构数据，以及在选择性自由基捕获剂存在下进行的光催化实验，导致阐明了一些先前关于 BaBiO 能带结构的观点未能解决或澄清的光催化过程的机制细节。对 XRD 数据的分析精修推断，所合成的 BaBiO 采用 C 对称性，而不是早期报道的 I 结构，而 DRS 光谱的 Tauc 图得出的带隙为 2.05 eV，范围为 1.1-2.25 eV，而其他人报告的范围为 1.1-2.25 eV；相应的平带电位为 1.61 eV (E) 和 -0.44 eV (E)。在可比的实验条件下，BaBiO 的光催化活性略高于知名的 Evonik P25 TiO 光催化剂。
