摘要
应用密度泛函理论GGA+Ud+Up方法,同时考虑TiO2中Ti 3d轨道和氧2p轨道的在位库仑修正以消除传统方法GGA或LDA中固有的自相互作用误差,研究了四种晶型TiO2(Rutile,Anatase,Brookite,TiO2(B))光催化剂的电子结构性质.对于Rutile,Anatase和Brookite,设定Ud=8eV,Up分别为6eV,4eV,4eV,计算得到的带隙值与实验值非常接近;而对于TiO2(B),Ud=4eV,Up=4eV时,计算得到的带隙值与实验值吻合较好.研究结果表明,在应用DFT+U方法时,同时考察氧p轨道电子的U值贡献时能获得更合理的结果.另外,计算了它们的电子和空穴的有效质量,比较而言,光激发载流子的迁移速率顺序为Anatase>Rutile>Brookite>TiO2(B),这与实验上Anatase光催化反应性能最优相一致.
The electronic structure properties of four kinds of crystalline TiO2photocatalysts were studied by using density functional theory GGA+Ud+Upmethod and considering in-situ Coulomb correction of Ti 3dorbit and O 2p orbit in TiO2to eliminate the inherent self-interaction error in the traditional GGA or LDA method.For Rutile,Anatase and Brookite,respectively,Ud=8eV,Up=6eV,4eV and 4eV.The calculated band gap value is very close to the experimental value,while for TiO2(B),Ud=4eV,Up=4eV,the calculated band gap value is in good agreement with the experimental value,which shows that when DFT+U method is used,the U-value contribution of O p orbital electrons can be more reasonable.Thus,the effective mass of the electron-holes is calculated.It is shown that the order of the migration rate of the photoexcited carriers is Anatase>Rutile>Brookite>TiO2(B),which is agreeable to the experimental result that photocatalytic reaction properties of Anatase is optimal.
作者
王松林
任君
李永祥
WANG Song-lin;REN Jun;LI Yong-xiang(School of Chemical Engineering and Technology,North University of China,Taiyuan 030051,China)
出处
《中北大学学报（自然科学版）》
CAS
2020年第6期532-537,共6页
Journal of North University of China(Natural Science Edition)
基金
国家自然科学基金资助项目(51473081)。
