Ti(Ⅳ)掺杂Bi_2O_3电子结构和可见光催化活性的原理  

Electron structure and photocatalytic activity of Ti(Ⅳ) doped Bi_2O_3

作　　者：殷立峰[1] 牛军峰[1] 沈珍瑶[1] 孙英[2] 

机构地区：[1]水环境模拟国家重点实验室北京师范大学环境学院,北京100875 [2]中国农业大学理学院,北京100193

出　　处：《中国科学：化学》2011年第3期509-515,共7页SCIENTIA SINICA Chimica

基　　金：国家高技术研究发展计划(2006AA06Z323);国家科技支撑计划(2008BAC32B06-3);水环境模拟国家重点实验室基金(08ESPCT-Z)资助

摘　　要：密度泛函理论(DFT)计算对掺杂体系新型环境光催化剂设计开发具有指导意义.基于DFT框架下的第一性原理平面波超软赝势方法(USPP),对α、β、γ、δ-Bi2O3晶体几何结构分别进行了优化计算,从理论上得到了Bi2O3的总体态密度(TDOS)和Bi、O原子的分波态密度(PDOS).在此基础上对Bi2O3超晶胞进行Ti(IV)的掺杂计算,讨论了Ti(IV)掺杂对各种Bi2O3的电子结构和光吸收特性的影响.结果表明Ti(IV)掺杂Bi2O3晶体后,Ti(IV)的3d轨道进入禁带并与O2p、Bi6p轨道作用,使禁带宽度(Eg)变小,Bi2O3的吸收边红移,从而有助于Bi2O3光催化活性的改善.通过水热合成法制备的Ti(IV)掺杂Bi2O3样品的紫外-可见光漫反射光谱验证了计算的结果.在光催化降解有机染料结晶紫的实验中,光催化剂活性的改善进一步得到证实.Density functional theory （DFT） plays an important role in the development of visible light responsive photocatalysts. Based on the first-principles plane-wave ultrasoft pseudopotential （USPP） method, the crystal structures of α, β, γ, and δ-Bi2O3 were optimally calculated for the total density of states （TDOS） and the partial density of states （PDOS） of Bi, O atoms. Then the calculation for Ti（IV） doped Bi2O3 supercell was carried out. The effects of Ti（IV）-doping on the electron structures and light absorption property of various Bi2O3 were analyzed. The results showed that Ti 3d orbital appeared in the forbidden band of Bi2O3 and hybridized with O 2p, Bi 6p orbitals. The narrowed band gap （Eg） and red-shift of light absorption edge should be responsible for the enhanced photocatalytic activity of Bi2O3. Then the β-Bi2O3 and Ti-doped β-Bi2O3 were prepared by a hydrothermal synthesis method. The improvement of the photocatalytic activity of Bi2O3 has also been verified by the characteristics of the UV-vis diffuse reflection spectrum and the experimental evaluation of the photocatalytic degradation of crystal violet in aqueous solution.

关 键 词：Ti(IV)掺杂 BI2O3 电子结构 可见光催化剂 密度泛函理论 

分 类 号：O643.36[理学—物理化学]