金属受体辅助S–O耦合作用改善六方相三氧化钨光解水性能的研究（英文）

Enhanced photochemical performance of hexagonal WO_3 by metal-assisted S–O coupling for solar-driven water splitting

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-WO_3)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-WO_3的带隙,且能够避免由于Sn、Pb单掺杂形成h-WO_3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-WO_3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-WO_3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-WO_3对可见光的吸收能力.这些结果表明,(Sn,S)共掺杂h-WO_3是一种在太阳光分解水领域有潜在应用前景的材料.

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 WO_3（h-WO_3）in order to improve their visible light photocatalytic activity.Results indicate that the（Sn,S）-and（Pb,S）-codoped h-WO_3 can realize a significant band gap reduction and prevent the formation of empty states in the valence band of h-WO_3,while Sn/Pb-monodoped h-WO_3 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-WO_3 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-WO_3 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-WO_3 is a promising material in solar-driven water splitting.