摘要
利用Materialsstudio软件建立了锐钛矿原胞模型,采用非金属C、N、S、P置换TiO2中O的方式进行掺杂,建立TiO1.875X0.125(2×1×1)(X为C、N、S、P)超晶胞,采用基于密度泛函理论(DensityFunctionalTheory,DFT)的Castep软件包对锐钛矿TiO2和TiO1.875X0.125的能带结构、态密度和光学性质进行分析。结果表明:非金属掺杂锐钛矿TiO2的带隙值较锐钛矿TiO2均减小,分别为0.57eV(TiO1.875C0.125)、1.93eV(TiO1.875N0.125)、1.30eV(TiO1.875S0.125)和0.21eV(TiO1.875P0.125),并且光吸收边界均出现了不同程度的红移(TiO1.875P0.125>TiO1.875C0.125>TiO1.875S0.125>TiO1.875N0.125)。非金属(C、N、S、P)掺杂均会窄化锐钛矿TiO2的禁带宽度且使能带变得致密,C、P掺杂材料的价带和导带均向低能量区偏移,而N、S掺杂材料的导带出现负移,价带偏移不明显。由于C-2p、N-2p、S-2p、P-3p轨道与O-2p和Ti-3d轨道的不同程度杂化耦合,禁带中不同位置出现了不同数量的杂质能级,进而形成新的可见光吸收区,并且可捕获价带电子,延长光生电子和空穴的复合时间,有利于提高光催化效率。其中,C和P掺杂锐钛矿TiO2的带宽较窄、带隙值较小、红移程度高,在可见光区光催化活性较高。
Anatase TiO 2 semiconductor cell and TiO 1.875 X 0.125(2×1×1)(X is C,N,S,P)with the replacement of O with C,N,S,P atom were produced by Materials studio software.Energy band structure,density of state(DOS)and optical properties were analysed by Castep software package based on density functional theory(DFT).The results showed that nonmetal doping led to the width of gap decreased to 0.57 eV(TiO 1.875 C 0.125),1.93 eV(TiO 1.875 N 0.125),1.30 eV(TiO 1.875 S 0.125)and 0.21 eV(TiO 1.875 P 0.125)and their adsoption band edge had different degree of red shifts toward the long wavelength(TiO 1.875 P 0.125>T iO 1.875 C 0.125>TiO 1.875 S 0.125>TiO 1.875 N 0.125).Nonmetal doping narrowed the band gap width and made the energy band denser.Valence band and condiction band of C and P doping both moved to the low energy area,in addition,the conduction band of N and S doping moved to the low energy area but valence band hardly moved.Different numbers of impurity energy levels were generated in different state of band gap due to the hybridization and coupling between C-2p,N-2p,S-2p,P-3p,O-2p and Ti-3d.The impurity energy levels generated new visible-light adsoption areas,catching electrons from valence band and inhibiting electronic/hole combination,which enhanced the photocatalytic activity.Above all,C,P doped anatase TiO 2 have narrower band width,narrower band gap,wider redshift and higher photocatalytic activity under visible-light.
作者
王冠宇
郭卫杰
刘迪
许德平
Wang Guanyu;Guo Weijie;Liu Di;Xu Deping(School of Chemical&Environmental Engineering,China)
出处
《矿业科学学报》
2020年第5期584-591,共8页
Journal of Mining Science and Technology
基金
国家自然科学基金(21806181)。
