LAUSR

Hybrid density functional calculations was used to comprehensively study the electronic structure of S-, Snand Pb-monodoped and (Sn, S)- and (Pb, S)-codoped hexagonal WO3 (h-WO3) in order to improve their visible light photocatalytic activity. Results indicate that the (Sn, S)- and (Pb, S)-codoped h-WO3 can realize a significant band gap reduction and prevent the formation of empty states in the valence band of h-WO3, while Sn/Pb-monodoped h-WO3 cannot, because in (Sn, S)- and (Pb, S)-codoping, the S-doping introduces the fully occupied S 3p states in the forbidden band gap of h-WO3 and the acceptor metals (Sn and Pb) would assist the coupling of the introduced S with its nearest O. In particular, the (Sn, S)-codoped h-WO3 has the narrowest band gap of 1.85 eV and highest reducing ability among the doped case. Moreover, the calculated optical absorption spectra show that (Sn, S)-codoping can improve the visible light absorption. In short, these results indicate that the (Sn, S)-codoped h-WO3 is a promising material in solar-driven water splitting.摘要本文采用杂化密度泛函理论计算研究了S、Sn、Pb单掺杂和(Sn, S)、(Pb, S)共掺杂六方相三氧化钨(h-WO3)材料的电子结构及其在可见光范围内的光催化特性. 结果表明: (Sn, S)和(Pb, S)共掺杂体系可有效减小h-WO3的带隙, 且能够避免由于Sn、Pb单掺杂形成h-WO3价带中空穴的现象. 这主要是因为在(Sn, S)和(Pb, S)共掺杂体系中, 金属受体(Sn、Pb)杂质的掺入会导致杂质S 原子与邻近的O 原子耦合,形成S–O 键, 该S–O 键的反键轨道在h-WO3的禁带中引入两条完全占据的杂质能级. 值得注意的是, (Sn, S)共掺杂可使h-WO3的带隙减小至1.85 eV, 同时赋予其最高的还原能力. 此外, (Sn, S)共掺杂也提高了h-WO3对可见光的吸收能力. 这些结果表明, (Sn, S)共掺杂h-WO3是一种在太阳光分解水领域有潜在应用前景的材料.