Pt掺杂锐钛矿相TiO_2光催化剂的微观机理研究

Study on the micro-mechanism of Pt-doped anatase TiO_2

采用第一性原理平面波超软赝势方法研究了Pt掺杂锐钛矿相TiO2的晶体结构、电子结构和光学性质,结果表明,Pt掺杂后锐钛矿相TiO2晶格产生畸变,晶胞体积增大晶胞内部八面体偶极矩增加;Pt5d轨道与O2p轨道、Ti3d轨道杂化,分别在价带顶和导带底产生杂质能级,禁带宽度变小,光吸收带边红移至可见光区。理论计算结果与文献报道的实验结果基本一致,较好地阐明了Pt掺杂提高锐钛矿相TiO2光催化性能的机理。

The crystal structures,electronic structures and optical properties of platinum-doped anatase TiO2 were calculated by first principles with plane-wave ultrasoft pseudopotential approach.The calculated results show that the lattice is distorted,the crystal cell volume and the octahedral dipole moments are increased;the impurity level both at the valence band top and the conduction band bottom are formed by Pt 5d orbit level with O 2p and Ti 3d orbit level hybridization which resulted in the energy gap narrowed and the red-shift of the light absorption wavelength.The theoretical calculation results are consistent with that of the experiment study reported,and give a good mechanism interpretation to the photocatalytic activity enhancement Pt-doped anatase TiO2.