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First-principles calculations of 0D/2D GQDs–MoS2 mixed van der Waals heterojunctions for photocatalysis: a transition from type I to type II.
- Source :
- Physical Chemistry Chemical Physics (PCCP); 4/14/2022, Vol. 24 Issue 14, p8529-8536, 8p
- Publication Year :
- 2022
-
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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14639076
- Volume :
- 24
- Issue :
- 14
- Database :
- Complementary Index
- Journal :
- Physical Chemistry Chemical Physics (PCCP)
- Publication Type :
- Academic Journal
- Accession number :
- 156188322
- Full Text :
- https://doi.org/10.1039/d1cp05448a