First-principles study on electronic structure and photocatalytic performance of Si,Ge,Zr and Sn doped SrTiO3
In this paper,electronic structures and photocatalytic performances of Si,Ge,Zr and Sn doped Sr-TiO3 were studied using density functional theory realized by QUANTUM ESPRESSO(QE)software package.The lattice constants of SrTiO3 obtained by using the generalized gradient approximation(GGA)are very consist-ent with the previous experimental data.At the same time,the lattice constants of SrTi0.875X0.125O3(X =Si,Ge,Zr,Sn)doped systems were obtained.The band gap values of SrTiO3 and SrTi0.875X0.125O3(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 photocata-lytic performance of five SrTiO3 systems,the band gap values of the five SrTiO3 systems were modified by using the scissors operator.The reduction potential(ECB)of the conduction band edge of the intrinsic SrTiO3 and four SrTi0.875X0.125O3(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(EVB)of the valence band edge corresponding to five SrTiO3 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 SrTi0.875X0.125O3(X = Zr,Sn)doping systems are improved compared with the intrinsic SrTiO3,while the redox property of SrTi0.875 Si0.125 O3 is reduced compared with the intrinsic SrTiO3.The relative positions of the band edges of the five Sr-TiO3 systems can meet the process of water splitting to generate H2 and O2.
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