α,β,γ,δ,ε,η-Bi_2O_3电子结构和光学性质的第一性原理研究  

First-principle Calculations on Electronic Structures and Optical Properties of α,β,γ,δ,ε,η-Bi_2O_3

作　　者：李坦[1] 张小超[1] 王凯[1] 李瑞[1] 樊彩梅[1] 

机构地区：[1]太原理工大学化学化工学院,太原030024

出　　处：《高等学校化学学报》2016年第5期920-927,共8页Chemical Journal of Chinese Universities

基　　金：国家自然科学青年基金(批准号:21506144);山西省青年自然科学基金(批准号:2014021019-3);山西省高等学校科技创新项目(批准号:2014115)资助~~

摘　　要：基于密度泛函理论的CASTEP模块研究了α,β,γ,δ,ε和η-Bi_2O_3晶型,计算分析了其几何结构、能带结构、电子态密度和光学性质.结果表明,α,ε和η相均为层状结构,其中,α和ε相为单层—Bi—O—结构,而η相为双层—Bi—O—结构;β,γ和δ相为—Bi_m—O_n—交错结构,其中δ相交错尤为密集,呈现导体特性.各晶相的导带均由Bi 6p态构成,价带由O__(2p)态起主导作用.电势电位分析结果表明,6种晶相价带电位均在H_2O/O_2之下,具有强氧化能力,与实验报道的光催化氧化能力大小顺序γ-Bi_2O_3>β-Bi_2O_3>α-Bi_2O_3>δ-Bi_2O_3一致,而导带还原电位低于H_2/H_2O,预测纯Bi_2O_3很难具备催化产氢能力.光学性质分析发现,γ和δ相的起始响应波长较大,说明其应具备红外激发的性质.这些结果可为获得偏红外激发和较宽光谱响应的Bi_2O_3材料研究提供理论基础,为研发和应用Bi_2O_3及其复合物提供重要的指导.A theoretical investigation on the geometric structures,band structures,densities of states and optical properties of Bi_2O_3 in six crystalline phases（ α,β,γ,δ,ε and η） was carried out using CASTEP（ Cambridge Sequential Total Energy Package） module based on the density functional theory. The calculation results show that the α,ε and η phases belong to the layered structure,in which α and ε phases are —Bi—O— single-layer structure and η phase is consisted of the —Bi—O— double-layers structure,while the β,γ,and δ phases are —Bi_m—O_n— staggered structure,in which the δ 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_（6 p）states,while the valence bands are contributed by O_2 pstates.The potential of the six phases are lower than the H_2 O/O_2,indicating that they have the higher oxidative ability,which is in good agreement with the reported experimental result（ γ-Bi_2O_3β-Bi_2O_3α-Bi_2O_3δ-Bi_2O_3） of the photocatalytic oxidative ability. The reduction potential of the conduction band is lower than H_2/H_2 O,we thus speculate that pure Bi_2O_3 has hardly the catalytic ability of hydrogen production. The γ and δ 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 Bi_2O_3 materials with partial infrared excitation and wide spectral response range,and afford significant guidance for the development and application in the Bi_2O_3-based materials.

关 键 词：Bi2O3晶相 第一性原理 电子结构 光学性质 

分 类 号：O641[理学—物理化学]