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氟掺杂提高单斜钒酸铋光催化活性的密度泛函理论研究
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摘要
本文基于密度泛函理论计算,研究了F掺杂对单斜BiVO_4体相和表面性质的影响。热力学计算结果表明,无论对于体相还是表面,F均易掺杂到O位,而且不会引起明显弛豫。电子结构计算表明,F掺杂在体相和表面均能在导带底引入自旋极化的能态。这个自旋极化的能态不仅能减小其带隙提高可见光利用率,还能有效捕获光生电子促进光生载流子的分离。H_2O在掺杂表面的吸附研究表明,表面F掺杂能显著增强表面与H_2O之间的氢键作用,从而提高其对H_2O的吸附能力。因此,我们认为F掺杂可能是提高单斜BiVO_4的光催化水分解活性的有效手段之一。
By means of density functional theory(DFT) computations, we investigated the variations of the bulk and surface properties of monoclinic BiVO_4 introduced by the F dopant.The results of thermodynamic stability calculations suggest that F atom should be easy to substitute O atom both in the bulk and on the surface.And both the bulk cells and surface cells were not severely distorted.The analysis of electronic structure shows that the F dopant should introduce spin-polarized energy states below the bottom of conduction band, which would contribute to improving the utilization ratio of visible light and the separation of photoinduced carriers.The simulation of H_2O adsorption on F doped surfaces indicates that the doping could obviously enhance the hydrogen bond between the H_2O molecule and F-doped surfaces, which should remarkably improve the adsorptive capacity of monoclinic BiVO_4 surfaces.Thus, we propose that F-doped should be one of promising strategies to enhanced photocatalytic activity of monoclinic BiVO_4.
引文
[1]Liu,S.W.;Yin,K.;Ren,W.S.;Cheng,B.;Yu,J.J.Mater.Chem.,2012,22:17759.

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