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First-principles calculations of 0D/2D GQDs-MoS 2 mixed van der Waals heterojunctions for photocatalysis: a transition from type I to type II.
- Source :
-
Physical chemistry chemical physics : PCCP [Phys Chem Chem Phys] 2022 Apr 06; Vol. 24 (14), pp. 8529-8536. Date of Electronic Publication: 2022 Apr 06. - Publication Year :
- 2022
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Abstract
- The fabrication of type II heterojunctions is an efficient strategy to facilitate charge separation in photocatalysis. Here, mixed dimensional 0D/2D van der Waals (vdW) heterostructures (graphene quantum dots (GQDs)-MoS <subscript>2</subscript> ) for generating hydrogen from water splitting are investigated based on density functional theory (DFT). The electronic and photocatalytic properties of three heterostructures, namely, C <subscript>6</subscript> H <subscript>6</subscript> -MoS <subscript>2</subscript> , C <subscript>24</subscript> H <subscript>12</subscript> -MoS <subscript>2</subscript> and C <subscript>32</subscript> H <subscript>14</subscript> -MoS <subscript>2</subscript> are estimated by analyzing the density of states, charge density difference, work function, Bader charge, absorption spectra and band alignment. The results indicated that the built-in electric fields from GQDs to MoS <subscript>2</subscript> boost charge separation. Meanwhile, all the GQDs-MoS <subscript>2</subscript> exhibit strong absorption in the visible light region. Surprisingly, the transition of heterojunctions from type I to type II is realized by tuning the size of GQDs. In particular, C <subscript>32</subscript> H <subscript>14</subscript> -MoS <subscript>2</subscript> with enhanced visible-light absorption and an appropriate band edge position, as a type II heterostructure, may be a promising photocatalyst for generating hydrogen from water splitting. Thus, in this work a novel type II 0D/2D nanocomposite as a photocatalyst is constructed that provides a strategy to regulate the type of heterostructure from the perspective of theoretical calculation.
Details
- Language :
- English
- ISSN :
- 1463-9084
- Volume :
- 24
- Issue :
- 14
- Database :
- MEDLINE
- Journal :
- Physical chemistry chemical physics : PCCP
- Publication Type :
- Academic Journal
- Accession number :
- 35348556
- Full Text :
- https://doi.org/10.1039/d1cp05448a