Institute of Chemistry for Functionalized Materials, School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian, Liaoning 116029, China.
Phys Chem Chem Phys. 2015 Sep 7;17(33):21611-21. doi: 10.1039/c5cp03005f. Epub 2015 Jul 30.
Doping of the SrTiO3 surface with non-metal atoms (X = C, N, F, Si, P, S, Cl, Se, Br and I) has been considered in a systematic study by performing periodic density functional theory calculations using the hybrid HSE06 functional, with the objective of improving its photocatalytic activity for water splitting under visible light. Our results found that the doping in the top layer of the SrTiO3(001) surface is energetically favored. An X (X = C, N and F) atom with a relatively small atomic radius tends to substitute the O atom in the TiO2-terminated surface, while the preferential occupation of the X (X = P, S, Cl, Se and Br) atom with larger atomic radius takes place at the O position in the SrO-terminated surface. X-doped surfaces (X = C, Si and P) show the presence of discrete midgap states, which are detrimental to photocatalysis. Due to the appearance of surface O 2p states, the band gap of the pure TiO2-terminated surface is calculated to be 2.56 eV, which is much narrower than that of bulk SrTiO3 (3.4 eV). Our results indicate that the band alignments of N-doped, Br-doped and I-doped SrTiO3(001) surfaces are well positioned for the feasibility of photo-oxidation and photo-reduction of water, which are promising for water splitting in the visible light region.
通过使用杂化 HSE06 泛函进行周期性密度泛函理论计算，对 SrTiO3 表面用非金属原子（X = C、N、F、Si、P、S、Cl、Se、Br 和 I）掺杂进行了系统研究，目的是提高其在可见光下分解水的光催化活性。我们的研究结果发现，SrTiO3(001)表面顶层的掺杂在能量上是有利的。相对原子半径较小的 X（X = C、N 和 F）原子倾向于取代 TiO2 终止表面的 O 原子，而相对原子半径较大的 X（X = P、S、Cl、Se 和 Br）原子则优先占据 SrO 终止表面的 O 位置。X 掺杂表面（X = C、Si 和 P）存在离散的带隙中间态，这对光催化不利。由于表面 O 2p 态的出现，纯 TiO2 终止表面的能带隙计算为 2.56 eV，远小于体相 SrTiO3（3.4 eV）的能带隙。我们的研究结果表明，N 掺杂、Br 掺杂和 I 掺杂 SrTiO3(001)表面的能带排列对于水的光氧化和光还原的可行性是有利的，这对于可见光区的水分解是有前途的。
