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摘要
A theoretical investigation on the geometric structures, band structures, densities of states and optical properties of Bi2O3 in six crystalline phases (alpha, beta, gamma, delta, epsilon and eta) was carried out using CASTEP ( Cambridge Sequential Total Energy Package) module based on the density functional theory. The calculation results show that the alpha, epsilon and eta phases belong to the layered structure, in which alpha and epsilon phases are -Bi-O- single-layer structure and eta phase is consisted of the -Bi-O- double-layers structure, while the beta, gamma, and delta phases are -Bi-m-O-n- staggered structure, in which the delta phase is intensively staggered and its band structure exhibits the conductor characteristic. The conduction bands of all the six crystalline phases are mainly generated by Bi-6p states, while the valence bands are contributed by O-2p states. The potential of the six phases are lower than the H2O/O-2, indicating that they have the higher oxidative ability, which is in good agreement with the reported experimental result(gamma-Bi2O3>beta-Bi2O3>alpha-Bi2O3 delta-Bi2O3) of the photocatalytic oxidative ability. The reduction potential of the conduction band is lower than H-2/H2O, we thus speculate that pure Bi2O3 has hardly the catalytic ability of hydrogen production. The gamma and delta phases have the longer initial response wavelengths, implying that they should have the infrared excitation property. Our calculations can provide basic and reliable theoretical data for the synthesis and study of Bi2O3 materials with partial infrared excitation and wide spectral response range, and afford significant guidance for the development and application in the Bi2O3-based materials.
- 出版日期2016-5-10
- 单位太原理工大学
