The Electronic Structure And Optical Properties Of La,Ce,Eu Doped TiO₂

As an important semiconductor photocatalyst, titanium dioxide has wide applications in many fields. It has been widely studied. However, anatase has a serious disadvantage that only little of the solar spectrum can be used for its photocatalytic capabilities due to its large band gap. Therefore, doping is significance for the development of enhance its photocatalytic properties.The lattice parameters, band structure, density of states, electron density difference and light absorption characteristics of La, Ce, Eu3+, Eu2+, Ce3+, Ce4+doped and La-Ce co-doped TiO2 in anatase phases are calculated based on the first-principles density functional theory pseudopotential method. Based on the theoretical results,the crystal structure, morphology, optical catalytic properties of La, Ce doped and co-doped TiO2 were characterized using XRD, SEM and UV-Vis.The experimental results are consistent with the theoretical ones.The following conclusions are obtained:The La, Ce co-doped anatase TiO2 bond length are changed, the lattice is distorted, band gap width decreases. After doped, impurity level appears, the conduction band shifts to lower energy, absorption band edge occurred different degrees of redshift, ultraviolet and visible light absorption coefficient increase,Which is advantageous to TiO2 response to visible light. Light absorption experiment results also verify the theoretical calculations. After co-doped optical absorption capacity has been enhanced. Theory and experiments show that the co-doped effect is stronger than single doped effect.After Eu3+, Eu2+ doped anatase TiO2, the bond length are changed, the lattice is distorted, impurity level appears, band gap width decreases, absorption band edge occurred different degrees of redshift, ultraviolet and visible light absorption coefficient increase. The Eu2+ doped has the strongest optical absorption characteristic.After Ce3+, Ce4+ doped anatase TiO2, the bond length are changed, the lattice is distorted, impurity level appears, band gap width decreases, absorptionband edge occurred different degrees of redshift, ultraviolet and visible light absorption coefficient increase, optical absorption capacity has been enhanced.Compared with Ce4+ doped effect, Ce3+ doped is more obvious.