Si,Ge,Zr和Sn掺杂SrTiO_(3)的电子结构和光催化性能第一性原理研究

First-principles study on electronic structure and photocatalytic performance of Si,Ge,Zr and Sn doped SrTiO_(3)

使用QUANTUM ESPRESSO(QE)软件包实现的密度泛函理论研究了Si, Ge, Zr和Sn掺杂SrTiO_(3)的结构,电子结构和光催化性能.使用广义梯度近似(GGA)获得SrTiO_(3)的晶格常数与先前的实验数据非常一致.同时,获得了SrTi_(0.875)X_(0.125)O_(3)(X=Si, Ge, Zr, Sn)四种掺杂体系的晶格常数. SrTiO_(3)和SrTi_(0.875)X_(0.125)O_(3)(X=Si, Ge, Zr, Sn)四种掺杂的带隙值分别1.853 eV、1.849 eV、1.916 eV、1.895 eV和1.925 eV.在研究五种SrTiO_(3)体系的光催化性能时,采用剪刀算符对五种SrTiO_(3)体系的带隙值进行修正.计算本征SrTiO_(3)和SrTi_(0.875)X_(0.125)O_(3)(X=Si, Ge, Zr, Sn)四种掺杂体系的导带带边的还原电势(ECB)分别是-0.782 eV、-0.736 eV、-0.776 eV、-0.800 eV和-0.791 eV.计算得到五种SrTiO_(3)体系对应的的价带带边的氧化电势(EVB)分别为:2.418 eV、2.460 eV、2.487 eV、2.442 eV和2.481 eV.从氧化还原性质方面来看,SrTi_(0.875)X_(0.125)O_(3)(X=Zr, Sn)两种掺杂体系相对于本征SrTiO_(3)的氧化还原性提高,SrTi_(0.875)Si_(0.125)O_(3)的相对于本征SrTiO_(3)还原性降低,五种SrTiO_(3)体系的带边相对位置能够满足H2O分裂产生H_(2)和O_(2)的过程.

In this paper,electronic structures and photocatalytic performances of Si,Ge,Zr and Sn doped SrTiO_(3) were studied using density functional theory realized by QUANTUM ESPRESSO(QE)software package.The lattice constants of SrTiO_(3) obtained by using the generalized gradient approximation(GGA)are very consistent with the previous experimental data.At the same time,the lattice constants of SrTi_(0.875)X_(0.125)O_(3)(X=Si,Ge,Zr,Sn)doped systems were obtained.The band gap values of SrTiO_(3) and SrTi_(0.875)X_(0.125)O_(3)(X=Si,Ge,Zr,Sn)are 1.853 eV,1.849 eV,1.916 eV,1.895 eV and 1.925 eV,respectively.When studying the photocatalytic performance of five SrTiO_(3) systems,the band gap values of the five SrTiO_(3) systems were modified by using the scissors operator.The reduction potential(E_(CB))of the conduction band edge of the intrinsic SrTiO_(3) and four SrTi_(0.875)X_(0.125)O_(3)(X=Si,Ge,Zr,Sn)doping systems were calculated to be-0.782 eV,-0.736 eV,-0.776 eV,-0.800 eV and-0.791 eV,respectively.The oxidation potentials(E_(VB))of the valence band edge corresponding to five SrTiO_(3) systems were calculated as 2.418 eV,2.460 eV,2.487 eV,2.442 eV and 2.481 eV,respectively.From the perspective of redox properties,the redox properties of the two SrTi_(0.875)X_(0.125)O_(3)(X=Zr,Sn)doping systems are improved compared with the intrinsic SrTiO_(3),while the redox property of SrTi_(0.875)Si_(0.125)O_(3) is reduced compared with the intrinsic SrTiO_(3).The relative positions of the band edges of the five SrTiO_(3) systems can meet the process of water splitting to generate H_(2) and O_(2).