Saiduzzaman Md, Akutsu Shuhei, Kumada Nobuhiro, Takei Takahiro, Yanagida Sayaka, Yamane Hisanori, Kusano Yoshihiro
Center for Crystal Science and Technology, University of Yamanashi, 7-32 Miyamae-cho, Kofu 400-8511, Japan.
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Inorg Chem. 2020 Apr 6;59(7):4950-4960. doi: 10.1021/acs.inorgchem.0c00213. Epub 2020 Mar 26.
Four types of bismuth oxides, NaBiO, NaBiO, α-BiO, and ε-BiO, were obtained by hydrothermal reactions using NaBiO·HO in NaOH solution. The crystal structure of a new phase (Na Bi)BiO ((NaBi)BiO) was determined by using single crystal X-ray diffraction data, and this compound was found to show a NaMnCl-related structure with a monoclinic system (space group, ) with the following lattice parameters: = 5.990 (2) Å, = 3.335 (2) Å, = 10.108 (2) Å, and β = 91.08 (3)°. The final -factors and were 0.041 and 0.090 (all data), respectively. The new phase was composed of mixed valence states of Bi (Bi and Bi, with a mean Bi valence of 4.30) with five distinct Bi sites, where two Bi (Bi1 and Bi2) fully occupied the distorted octahedral sites and three Bi (Bi3, Bi4, and Bi5) were statistically distributed at the split sites with Na (Na3, Na4, and Na5). The Na6 site is fully occupied. The distorted BiO octahedra formed one-dimensional chains via edge-sharing along the -axis, with the chains held by Bi/Na split sites. The structural feature except for the split distribution of Bi/Na was classified as a NaMnCl-type structure. DFT calculations based on a model discounting the split distribution of Bi/Na indicated that Bi 6s and O 2p orbitals form sp hybridization at the conduction band. This new mixed valence bismuth oxide exhibited photocatalytic activity for phenol degradation under visible light irradiation. In addition to NaBiO, the hydrothermal reaction using NaBiO·HO in NaOH solution yielded micrometer-sized single crystals of an ilmenite-type NaBiO and two polymorphs of bismuth oxides with monoclinic (α-BiO) and orthorhombic (ε-BiO) structures, depending on the reaction temperature and NaOH concentration.
通过在NaOH溶液中使用NaBiO·HO进行水热反应，得到了四种氧化铋，即NaBiO、NaBiO、α-BiO和ε-BiO。利用单晶X射线衍射数据确定了一种新相（(NaBi)BiO）的晶体结构，发现该化合物呈现出与NaMnCl相关的单斜晶系结构（空间群， ），其晶格参数如下： = 5.990 (2) Å， = 3.335 (2) Å， = 10.108 (2) Å，β = 91.08 (3)°。最终的 因子 和 分别为0.041和0.090（所有数据）。新相由Bi的混合价态（Bi 和Bi，平均Bi价为4.30）组成，有五个不同的Bi位点，其中两个Bi（Bi1和Bi2）完全占据扭曲的八面体位点，三个Bi（Bi3、Bi4和Bi5）与Na（Na3、Na4和Na5）统计分布在分裂位点。Na6位点被完全占据。扭曲的BiO八面体通过沿 -轴的边共享形成一维链，这些链由Bi/Na分裂位点维系。除了Bi/Na的分裂分布外，该结构特征被归类为NaMnCl型结构。基于忽略Bi/Na分裂分布的模型进行的DFT计算表明，Bi 6s和O 2p轨道在导带处形成sp杂化。这种新型混合价氧化铋在可见光照射下对苯酚降解表现出光催化活性。除了NaBiO外，在NaOH溶液中使用NaBiO·HO进行水热反应，根据反应温度和NaOH浓度，还生成了微米级钛铁矿型NaBiO单晶以及两种具有单斜（α-BiO）和正交（ε-BiO）结构的氧化铋多晶型物。
