Density functional theory calculation on two-dimensional MoS2/BiOX (X = Cl, Br, I) van der Waals heterostructures for photocatalytic action
Abstract
Bismuth oxyhalide (BiOX)-based heterostructures have attracted much attention due to their promotion effect on photocatalytic performance. Nonetheless, there is a lack of theoretical understanding on the relationship between the BiOX-induced interface and the enhancement of photocatalytic activity. In the present work, density functional theory (DFT) calculations were conducted to investigate the energy band structure, charge transfer and optic properties of layered MoS2/BiOX (X = Cl, Br, I) van der Waals (vdW) heterojunctions. All the MoS2/BiOX heterojunctions have lower band gaps, smaller effective mass and better light absorption ability than BiOX monolayers. Moreover, electrons transfer from MoS2 to BiOX, and MoS2/BiOX heterojunctions show typical type-II band arrangement. Importantly, MoS2/BiOI presents significant performance in the carrier mobility and light absorption ability among the three heterostructures, which can facilitate effective separation of photo-generated electron-hole pairs and enhance photocatalytic activity. It is disclosed that the band edges MoS2/BiOX are suitable for the photocatalytic decomposition of water into oxygen. It is especially so for MoS2/BiOI which can affect full photocatalytic water splitting. The results clarify why the combination of MoS2 and BiOX for the generation of MoS2/BiOX vdW heterojunctions could result in excellent photocatalytic activity, and disclose why MoS2/BiOI is the best among the three for photocatalytic water splitting.
- Publication:
-
Applied Surface Science
- Pub Date:
- October 2019
- DOI:
- 10.1016/j.apsusc.2019.06.201
- Bibcode:
- 2019ApSS..492..157G
- Keywords:
-
- Two-dimensional material;
- MoS<SUB>2</SUB>/BiOX;
- Heterostructure;
- Photocatalytic action